The source of this uncorrected OCR text may be viewed in the DjVu format at: http://fax.libs.uga.edu/J84xIx49x89x82x04/ or http://purl.galileo.usg.edu/ugafax/J84xIx49x89x82x04/ FWS/OBS-82/04 November 1982 THE ECOLOGY OF SOUTHEASTERN SHRUB BOGS (POCOSINS) AND CAROLINA BAYS: A COMMUNITY PROFILE by Rebecca R. Sharitz and J. Whitfleld Gibbons Savannah River Ecology Laboratory Alken. SC 29801 Project Officer Edward C. Pendleton National Coastal Ecosystems Team U.S. Fish and Wildlife Service 1010 Gause Boulevard Slldell. LA 70458 Performed for National Coastal Ecosystems Team Division of Biological Services Fish and Wildlife Service U.S. Department of the Interior Washington. DC 20240 and Region 4 Fish and Wildlife Service U.S. Department of the Interior 75 Spr'ng Street, SW Atlanta. GA 30303 The findings 1n this report are not to be construed as an official U.S. Fish and Wildlife Service position unless so designated by other authorized documents. PREFACE Library of Congress Card Number : 82-600630 This report should be cited as: Sharitz, R.R., and J.W.'Gibbons. 1982. The ecology of southeastern shrub bogs (poco- sins) and Carolina bays: a community profile. U.S. F1sh and Wildlife Service, Division of Biological Services, Washington, D.C. FWS/OBS-82/04. 93 pp. This report Is one of a series of U. S. F1sh and Wildlife Service Community Profiles synthesizing the available literature for selected critical eco systems Into comprehensive and definitive reference sources. The objective of this particular account is to review the infor mation available on the shrub bog com munities, primarily pocosins but also including many Carolina bays, of the mid- Atlantic Coastal Plain. Both of these ecosystems are Included under the same community profile because they frequently exhibit similar vegetatlonal character istics, have overlapping geographical ranges, and usually have low nutrient, peaty soil conditions. The combination of similar environ mental conditions and the regional overlap of the two ecosystems results in their having similar, species compositions. They are generally distinguishable, however, because of the distinctive morphology of Carolina bays (oval-shaped depressions with identifiable margins) and clearly different geologic origins, although dis agreement exists about how both pocosins and Carolina bays were formed. Nonethe less, they share 1n being the major sites of shrub bog communities on the mid- Atlantic Coastal Plain. s These shrub bog communities are under severe environmental impact throughout the Southeast although the major threats vary in different areas. Most man-related environmental alterations have occurred because pocosins and Carolina bays can be drained and the land used for agricul tural, forestry, or urban purposes and because they often have peaty soils, which may be commercially valuable. Because of previous and continuing efforts to use or alter these areas for commercial purposes, the amount of remaining natural habitat diminishes annually. The shrub bog community of pocosin and Carolina bay ecosystems Is one of the least-studied, most poorly understood of the natural wetlands in the Eastern United States, a fact that makes the rapid dis appearance of these habitats due to the environmental alterations associated with land use and development of critical importance. This report will provide a synthesis of what 1s currently known about the geologic origins, hydrology, soil con ditions, water quality, biota and general ecology of these ecosystems. A considera tion of the community as a whole reveals major gaps in our knowledge of its struc ture and dynamics at all levels. The limited information already available clearly documents the close environmental tie between coastal pocosins and contigu ous estuaries. A strong Interaction between Carolina bays and mobile animals from surrounding terrestrial habitats can also be demonstrated. This community profile addresses Information gaps which still exist about the significant environ mental Interactions between shrub bog communities and surrounding habitats. The information in this community profile should be useful to all environ mental planning groups, ecosystem mana gers, and concerned laymen 1n the Atlantic Coastal Plain, as well as to students and professional wetland ecologists. The quantitative presentations in figures, tables, and text will permit easy access to detailed Information about specific qualities and characteristics of the habi tats. Thus, the document should be valu able for report writing, planning environ-, mental assessment studies, preliminary determinations of potential Impacts of N land management, or general Information for formal courses on the topic of natural wetlands. Such Information on environ mental impact, rate of habitat loss, and gaps In our knowledge about these systems should Interest all ecologlsts, environ mental planners, and environmentally aware citizens. An extensive, thorough and cur rent bibliography is provided for anyone wishing to pursue particular topics In depth. The authors accept full responsibil ity for all statements, Interpretations, citations of other investigators, and original data presented. Any questions or comments about or requests for this publication may be directed to: Information Transfer Specialist National Coastal Ecosystems Team U. S. F1sh and Wildlife Service NASA/SIidel Computer Complex 1010 Cause Boulevard SI 1dell, LA 70458 CONTENTS PREFACE ..................................... 111 FIGURES ..................................... vi TABLES ...................................... viii ACKNOWLEDGMENTS ................................. 1x INTRODUCTION COMMUNITY PROFILE BACKGROUND AND OBJECTIVES: SHRUB BOGS OF THE ATLANTIC COASTAL PLAIN ............. 1 CHAPTER 1. DESCRIPTION OF SHRUB BOGS OF .THE ATLANTIC COASTAL PLAIN ..... 5 1.1 Definitions of Shrub Bogs, Pocosins, Carolina Bays, and Similar Ecosystems ...................... 5 1.2 Geographic Distribution of Pocosins and Carolina Bays ...... 10 1.3 Theories of Geologic Origin ................... 12 CHAPTER 2. PHYSICAL AND CHEMICAL CHARACTERISTICS. .............. 16 i 2.1 Size and Morphology of Community Types .............. 16 i 2.2 Substrate Conditions ....................... 16 2.3 Hydrologie Characteristics .................... 20 CHAPTER 3. BIOLOGICAL FEATURES ....................... 27 3.1 Plant Community Composition ................... 27 3.2 Animal Community Composition ................... 51 3.3 Endangered and Threatened Species ................ 59 3.4 Pocosins and Carolina Bays as Refuge Areas ............ 59 3.5 Trophic Relationships in Pocosin and Carolina Bay Ecosystems .......................... 60 CHAPTER 4. INFLUENCE OF HUMAN ACTIVITIES ON POCOSINS AND CAROLINA BAYS. .......................... 62 4.1 Historical Perspectives ..................... 62 4.2 Current Land Management Practices and Perturbations ....... 63 4.3 Current Ownership of Pocosins and Carolina Bays ......... 70 4.4 Recommendations for Research ................... 70 CHAPTER 5. RECOMMENDATIONS FOR CONSERVATION, PRESERVATION AND MANAGEMENT .......................... 74 REFERENCES ......'.............................. 76 FIGURES Number Page 1 Evergreen shrub bog pocosin 1n.Dare County, NC ............ 2 2 Two aspects of a typical Carolina bay, showing gradation In vegetation types .......................... 3 3 The relation of shrub bogs, pocoslns, and Carolina bays to each other and to the general class of palustrine wetlands ...... 5 4 Habitats In eastern North Carolina that are Identified as pocosin wetlands ........................... 7 5 South Atlantic Coastal Plain showing distribution of Carolina bays ............................. 9 6 Distribution of blackland soils in North Carolina ........... 11 7 Aerial comparison of two Carolina bay area densities ......... 12 8 Conceptual model of one proposed means of pocosin formation and development in flat, Inter^stream areas of lower Coastal Plain terraces ....'................ 15 9 Section and plan views of a typical Carolina bay, indicating key morphological features, soil profiles, and vegetation types .... 17 10 Soil types In North Carolina's Green Swamp pocosin .......... 19 11 Relationships among precipitation, evapotranspiration, and streamflow in a pocosin habitat .................. 21 12 Water level changes in two Carolina bays as influenced by precipitation and temperature ................... 25 (a) Mean monthly changes 1n water level, 1975-1981 .......... 25 (b) Changes in water level at Ellenton Bay .............. 25 (c) Seasonal drops in water level due to evapotranspiration at Ellenton Bay ......................... 25 (d) Changes in monthly mean water levels due to temperature ..... 25 13 Representative cross section through the Croatan National Forest pocosin substrates ....................... 28 14 Comparison of two types of pocosin habitats .............. 30 15 Vegetation types In Green Swamp, NC .................. 31 16 Dominant woody plant species of pocosin communities .......... 36 17 Major woody plant community cover classes in the Green Swamp, NC . . . 38 18 Proposed relationships among vegetation types, hydroperiod, and fire 1n pocosin habitats ....................... 45 19 The pitcher plant (Sarracenia purpurea) is adapted to nutrient- poor pocosin soils .......................... 47 20 Aerial view of vegetational zone pattern around a Carolina bay .... 48 21 Vegetation types of a Carolina bay that are characteristic of many undisturbed sites ........................ 49 22 The pine barrens treefrog (Hyla andersoni), an amphibian species indigenous to pocosin h~a~l>1tatsT ............... ^52 -23 The black bear (Ursus americanus), a major game species dependent on pocosin habitat in the lower Coastal Plain of North Carolina .... 53 24 A drift fence with pitfall traps at Ellenton Bay, SC ......... 57 25 A "gâter hole," indicating how a single species, the American v alligator (Alligator mississipplensis). can influence the ecology of a Carolina bay ...........'............ 58 x vl Number 26 27 28 29 30 31 Page Species adapted to fluctuating water levels characteristic 5g of Carolina bays ••••:•••'••: l-l,! '„* •••••••••' General pattern of ownership of pocosin habitats ot ^ Pocos1naSrainage'for*agricultural or forestry management ....... 64 Drought conditions in a ditched Carolina Bay . . . . . . . . - • • • • JD Aerial view of Carolina bay habitats in an agricultural region .... 66 Peat mining in a pocosin habitat ..........••'•••••• vti TABLES ACKNOWLEDGMENTS 4 5 6 7 8 9 Substrate characteristics of 13 pocosins in the Coastal Plain of South Carolina ............. Substrate characteristics of five Carolina bays in northeastern South Carolina .......... (a) (b) Comparison of water quality data from a natural pocosin stream with data from three drainage ditches in the same area .... Comparison of mean annual concentrations of constituents of pocosin seepage and farm ditch water during the clearing and drainage phase of wetlands development .......... Water quality parameters of seven Carolina bays in South Carolina .' (a) Classification of pocosin communities in the Green Swamp . . . (b) Associated communities peripheral to pocosins ........ Density and basal area of trees in a pocosin in South Carolina ! '. Density and transect cover of shrubs, woody vines, and tree seedlings in a pocosin in South Carolina ............. Comparison of various geological and ecological parameters'of pocosins, pine savannas, and bay forests in South Carolina . . . Secondary productivity associated with Carolina bay habitats . . . Page 18 20 23 23 24 34 35 ,39 40 44 55 We are grateful to numerous individ uals for their contributions to the com pletion of this project. We particularly thank C. J. Richardson (Duke University), C. B. McDonald, A. N. Ash, and M. M. Brinson (East Carolina University), and B. J. Cope!and (North Carolina State Univer sity) for instructive comments and infor mation about the shrub bogs in North Carolina. Resource material was provided by R. W. Skaggs (North Carolina State Uni versity), C. C. Daniel, III (Geological Survey, Raleigh), and T. M. Williams (Belle W. Baruch Forest Science Insti tute). C. B. McDonald and A. N. Ash spent time with us in the field visiting a vari ety of pocosin habitats in North Carolina and graciously provided illustrative mate rial for use in the report. A number of reviewers, including A. N. Ash, C. B. McDonald, and L. J. Otte (East Carolina University), C. J. Richard son and N. L. Christensen (Duke Univer sity), E. C. Pendleton and J. M. Hefner (U. S. Fish and Wildlife Service), C. A. Gresham (Clemson University) and J. F. Schalles (Creighton University), provided useful comments on an early draft. Members of the National Coastal Ecosystems Team (NCET) staff, especially W. M. Kitchens and E. C. Pendleton, were extremely help ful in offering guidance and suggestions. G. Farris, S. Lauritzen, and E. Krebs of NCET provided editorial, layout, and word- processing assistance, repectively; G. Golden assisted in drafting. We thank members of the University of Georgia's Savannah River Ecology Labora tory (SREL) staff who participated in re search cited in this document, T. Willing- ham who typed many copies of the manu script, J. B. Coleman who drew some of the figures, and L. R. Bost who helped with proofreading and preparation of the bibli ography. Data collection and manuscript preparation were aided by contract EY-76- C-09-0819 between the U. S. Department of Energy and the University of Georgia. fx INTRODUCTION COMMUNITY PROFILE BACKGROUND AND OBJECTIVES: SHRUB BOGS OF THE ATLANTIC COASTAL PLAIN The recognition and appreciation that natural wetlands are a valuable, non- renewable resource that can provide criti cal or essential habitat for natural vege tation and wildlife, including non-game and endangered species, are becoming wide spread among government, academic, and even commercial organizations. This con cern has led to establishment of Federal and State regulations (for example Execu tive Order 11990, Protection of Wetlands) to protect these natural systems and their associated flora and fauna. Understandably, initial attention by most interested groups focused on large bodies of permanent water such as estua ries, major lake systems, and rivers or streams which supported obvious game or commercial enterprises. When industrial, agricultural, or urban impacts on these large aquatic areas affected commercial and sports fisheries interests or the hunting of waterfowl, environmental con cerns quickly became an issue. Resolution of the complex of environmental, legal, ethical, and other issues surrounding the best approaches of preserving, managing, or utilizing natural wetlands is not likely to be attained in the near future. It is agreed, however, that our basic knowledge of the structure and function of most natural systems is woefully inade quate for us to make prudent decisions about the optimal management (or non- management) approach. Far too little is known about the life histories of most plants and animals inhabiting aquatic areas. Biological surprises about even the most thoroughly studied species emerge monthly in professional journals (e.g., Echelle and Mosier 1981; Fairchild 1981), reinforcing the awareness that we know far too little about the ecology of most natu ral systems to be able to exercise rea sonable judgment about how these systems should interface with our agro-industrial society. Among the natural wetlands that are most poorly studied are two types re stricted to the Atlantic Coastal Plain and abundant from southern Virginia to north ern Florida. These wetland ecosystems— pocosins (Figure 1) and Carolina bays (Figure 2)~share a common feature of be ing systems of low-nutrient status that in most instances do not have permanent standing water, but are strongly influ enced by the hydrologie regime. The vege tation of pocosins and of many extant Carolina bays is dominated by pines and broadleaved evergreen shrubs or low trees that are generally but not always growing on highly organic or peat soils. Man's activities have imposed a vari ety of environmental modifications and ecological changes in pocosin and Carolina bay ecosystems. Subsequent to regional timber removal in the early development of the Southeast, pocosin ecosystems have generally been considered of low economic value for agriculture, although they have recently become recognized as a source of peat. In regions of excessively drained soils, Carolina bays have commonly been farmed because they are areas of higher soil moisture. Few studies, however, have been carried out to assess the regional importance of either ecosystem in terms of faunal and floral dependence and utiliza tion. It is not known how critical a pocosin or a Carolina bay is to regional wildlife. For example, black bears are characteristically encountered in pocosins of eastern North Carolina, primarily because these ecosystems contain some of the few natural areas left in the region. Are present-day land management practices jeopardizing the future of cer tain plants and animals that rely on such natural habitats for feeding or breeding sites or other purposes? The extent of man's alteration of these wetlands cannot be determined. Dur ing colonization, widespread timbering occurred throughout the Coastal Plain re gion. Although such logging was not exclu sively in pocosins or Carolina bays, these habitats were not spared from considerable tree removal. Thus, major losses of Atlan tic white cedar, cypress, and black gum probably occurred. As a result, the orig inal vegetationa characteristics of many localities are unknown today. The shrub bog community may be second-growth in some instances, following logging of the orig inal forest species. In other areas, par ticularly in smaller Carolina bays, an original evergreen shrub vegetation may have been altered or removed by farming operations so that the shrub community is sparse or absent today. Because of the peat soil feature characteristic of many pocosins, large expanses of pocosin vegetation may have been burned during dry periods in early historical and recent times. A major modern impact is the removal of peat for commercial purposes. The highly organic soil can be processed to produce methanol or sold as a mulching agent for horti cultural operations or home use. Although at the present time peat has been mined only experimentally in the major pocosin areas of North Carolina, peat-methanol gasification operations are scheduled for future development. Thus, there is poten tial that thousands of acres of natural pocosin habitat could succumb to the commercial efforts of peat mining in the Carolinas. Major changes have also occurred in the hydrologie regimes of many pocosins and Carolina bays, primarily because wet f ' t '. • • /•» " •— v •* - J " - +- •j . : .*; vt • v -.-. Figure I.Evergreen shrub bog pocosin in Dare County, NC. co CO T- C = C O _. o < .C "5 3 01 (D « « «n «£ *x o 0) O S CO 3 c DC CO o « » " jS'V ri ^-'/S'i/â^^^ 'x-^ ;s«i^ r I 'T-/MW/) "'T ,.•'* • V "- -.^^V a ,-< of tfflL» . •/ * r.f ^\ *• xvx: s: ,-~ t -t?*5^ - w •*• A. • Il «E .E O « c (D W . » oo =- 6 broadleaved evergreen; water regime: saturated; water chemistry: fresh-acid; and soil: medisaprist.2 The definition of pocosin is con founded by various terminologies that have arisen among different professions. For example, pine-dominated flatwoods occur ring in areas with prolonged hydroperiods may be included in a forester's defini tion, whereas a hydrologist might consider only those shrub bogs occurring in broad, undrained interstream areas to be true pocosins. Because of the various defini tions and the similarities between pocosin vegetation and other plant communities such as bay forests, some of the material in this review may be taken from or ap plied to Coastal Plain wetlands that are closely related to pocosins but do not fit the ecological definition in all aspects. Possible successional relationships among these various wetland communities are dis cussed in Chapter 3. In summary, for the purposes of this community profile, pocosins are defined as freshwater wetland ecosystems character ized by broadleaved evergreen shrubs or low trees, commonly including pond pine, and commonly growing on highly organic soils that have developed in areas of poor drainage. Their present range of occur rence is the Atlantic Coastal Plain from southern Virginia to northern Florida. Carolina Bays Carolina bay ecosystems are formed in elliptical depressions which occur abun dantly in a broad band across the Coastal Plain province of the Southeastern United States (Figure 5). Some bays are less than 50 m (162 ft) in length; an unusually large one (Lake Waccamaw in North Caro lina) is more than 8 km (5 mi) long. These puzzling physiographic features of the landscape present a remarkable consis tency of shape and degree of parallelism in compass orientation along their axes. Called "bays" by early European pioneers who observed the evergreen shrubs and bay Medisaprist soils are well-decomposed organic soils (histosols) with an organic depth greater than 40 cm (16 inches). trees typically growing on their margins (Figure 2), these ovate wetlands afford suitable habitat for a vast assortment of plants and animals. Colloquial names such as "highland pond" or "wet weather lake" indicate the dependency of Carolina bay ecosystems upon rainfall and their lack of association with other lentic (still water) or lotie (flowing water) habitats. They character istically have no tributary streams, are not spring-fed, and rely on direct precip itation and run-off to maintain water volume. Groundwater recharge has been suggested as an additional source in some situations (Schalles 1979). Evaporative water loss, a temperature-dependent phe nomenon, reduces water volume and can result in the complete drying of shallow bays. Thus, many smaller Carolina bay depressions contain temporary aquatic hab itats that may dry up seasonally or for longer intervals under local conditions of low precipitation or regional drought. Because of extensive variability in size, depth, substrate conditions, and geographic location, Carolina bays do not have a single characteristic vegetation type. Many, including Jerome Bog (Buell 1946a) and Rockyhock Bay (Whitehead 1981) in North Carolina, contain evergreen shrub bogs or pocosins. Others contain lakes (Frey 1949), herbaceous marshes (Wharton 1978), or swamps (Porcher 1966). Still others, such as Ellenton Bay in South Car olina (Sharitz and Gibbons 1982) may have once supported forest or shrub communi ties, but have been severely modified by agricultural practices. Both the natural unaltered plant communities and the direc tion and rate of successional change in Carolina bays following disturbance are highly dependent upon,environmental var iables such as^ water level and fire. Therefore, a particular community type does not necessarily represent a particu lar stage of succession. For more ' than 300 years, natural habitats in the-1 region encompassing Caro lina bays have been influenced by human alteration as a consequence of agricul ture, forestry, industry, and 'other land management. These impacts, in addition to any burning by Indians (Wells and Boyce 1953b), have left unanswerable the CHOWAN ROANOKE PAMLICO NEUSE CAPE FEAR LAKE WACCAMAW COOPER COMBAHEE BROAD SAVANNAH OGEECHEE <$> ^ -. A^ . • if f. '•' '* :" :lt.\ * '-A» •• -* X to \ a • ' ^ t* - •*-.£ '» ^fc^ j« ^'l| GREAT DISMAL SWAMP -*-^V-ALBEMARLE SOUND - \ ™ LAKE PHELPS i*. >!' ! \ LAKE ^-^ " ' MATTAMUSKEET -*—-W- PAMLICO SOUND ^^'CAPE HATTERAS - GREAT DOVER SWAMP OPEN GROUND SWAMP A •. CROATAN NATIONAL FOREST CAPE LOOKOUT HOFMANN FOREST ANGOLA BAY HOLLY SHELTER SWAMP GREEN SWAMP CAPE FEAR Figure 6. Distribution of blackland soils (organic soils and dark-surfaced mineral soils) in North Carolina (Lilly 1981b in Pocosin Wetlands: An Integrated Analvaia oj Coastal Plain Freshwater Bogs in North Carolina, ed. C. J. Richardson. Copyright 1981 by Hutchinson Ross Publ. Co., Stroudsburg, PA. Reprinted by permission of the publisher). 10 11 (1952), are found in the Carolinas (North Carolina Natural Heritage Program unpub lished data, cited by Richardson 1982). It is difficult to estimate the total area covered by Carolina bays because they are non-contiguous in distribution, and many may have boundaries that are hard to rec ognize, may be obscured by farming or other land management or development practices, or may partly overlap .each other. The geographic range of Carolina bays encompasses approximately 23,310 km2 (9000 mi2). High density area, Bladen County, NC (Photograph by Charles E.Roe, North Carolina Natural Heritage Program.) Low density area. Barnwell County, SC Figure 7. Aerial comparison of two Carolina bay area densities. Neither pocosins nor Carolina bays demonstrate clear gradients in geomorphol- ogy or in species composition throughout their range of occurrence, although cer tain regional differences nay be recogniz able. For example, directional orienta tion of Carolina bays may show a slight geographic variation (Johnson 1942a), as described in Chapter 2. The total acreage of land occupied by pocosin wetlands on the Coastal Plain decreases from north to south in accordance with changes in the topography and geology. Although organic soils supporting pocosin vegetation may develop under several geologic situations, flat interstream areas"of the lower Coast al Plain terraces in North Carolina sup port the greatest expanse of pocosin vege tation. In South Carolina where pocosin ecosystems are more restricted in area, they occur chiefly in depressions associ ated with ridge and swale topography and in Carolina bays. Likewise, certain dif ferences in the characteristic species may be recognizable in pocosin or Carolina bay communities throughout their range. Wood- well (1956) classed pocosins according to their dominant shrub species and reported a shift in species dominance along a north-south gradient and following fire (see Chapter 3). The North Carolina poco sin communities represent the northern range extensions for certain species, including loblolly bay. Similar geo graphic patterns of species distribution may have become obscured by disturbance from natural causes or from land manage ment practices. 1.3 THEORIES OF GEOLOGIC ORIGIN Pocosins On the basis of the most thoroughly studied pocosin habitats—those in the Coastal Plain of North Carolina (Richard son 1981a)—these wetland communities be gan to develop following the Wisconsin Ice Age, about 15,000 years ago. Daniel (1981) described the geologic processes that led to the development of these areas. More than 75,000 years ago prior to the last expansion of the polar ice cap, the level of the Atlantic Ocean in the Southeast was 13 to 15 m (approximately 45 to-50 ft) higher than at present. During the Wis consin Ice Age, however, the sea level dropped to as much as 120 m (about 400 ft) below its present level and exposed large areas of the Continental Shelf. Because sea levels during the Wisconsin Age were much lower than at present, fast-flowing rivers cut through the Coastal Plain ter races to the Atlantic Ocean. During the next several thousand years as the ice receded, sea levels gradually rose ( - 30 cm/century, Milliman and Emery 1968) and brought about major changes in the hydrology of the Coastal Plain. One theory of pocosin formation relies on the assumption that during this period river flows were slowed and organic sediment loads were deposited in the interstream areas as the lotie (flowing) systems shifted to near-lentic (or slow- moving) aquatic systems (Daniel 1981). Aquatic plants began to grow in these shallow bodies of water, adding to the accumulation of sediments and the buildup of aquatic debris. Concomitant with the buildup in organic sediments and the cli matic warming trend that accompanied the end of the Wisconsin Ice Age, the cooler- climate, boreal forest communities were gradually eliminated (Whitehead 1972) and replaced with hardwood forests, swamps, bogs, and marshes. In the nutrient-poor areas often associated with the buildup of deep peat, evergreen shrub forests became predominant. It is assumed that wet habitats with a propensity for buildup of organic soils developed as a consequence of a shallow water table, large distance between streams (both resulting in slow runoff and subsequent accumulation of water), and rainfall that has exceeded evapotranspira tion (Daniels et al. 1977). The accumula tions of peat that would ultimately form the Coastal Plain pocosins generally began between 8,000 and 10,000 years before pre sent (B. P.) (Daniel 1981). For example, radiocarbon dating of the earliest organic sediments in the Great Dismal Swamp of Virginia indicates that these peats were formed about 8,900 ± 160 years ago (Oaks and Coch 1973). However, a mantle of organic deposits in the Hofmann Forest of North Carolina may have begun as long ago as 220,000 years. Radiocarbon dates of sediment profiles from other sites (e.g., Chesapeake Bay, Harrison et al. 1965) generally indicate ages of 8,000 to 15,000 years B. P. Additional evidence gained by matching pollen profiles from pocosin peat with known floral succession patterns associated with the glacial retreat sup ports the assumption that the pocosin wet lands developed between 10,000 and 12,000 years ago (Otte 1981). Otte (1981) challenged the theory of pocosin development in stream valleys and flat interstream areas as a consequence of blocked drainage associated with sea level rise. He pointed out that 10,000 to 12,000 years ago the sea level was approximately 25 m (81 ft) below the present level and many miles eastward of the present shore line. He contended that the position of the sea at that time was so far removed from the sites of development of the blocked drainage systems that it is un likely that sea level could have been the major controlling factor in the develop ment of these wetlands. Furthermore, Otte noted that pocosins have developed in only a portion of the drainage systems on the Coastal Plain, not in all. This evidence also strongly suggests a non-sea-level cause of pocosin formation. If Otte's theory is correct, the origin of the drainage blockages that resulted in poco sin formation in certain stream systems is as yet unknown. Four different types of geologic sit uations are considered to support pocosin communities in the southeastern Coastal Plain. These are (1) flat areas associated with blocked stream drainage on the lower terraces (Figure 8), (2) Carolina bays, (3) areas of ridge and swale topography between relict beaches and dune ridges (Woodwell 1956), and (4) springs and stream heads of the upper Coastal Plain area (Wells 1932; Christensen et al. 1981). In addition, this evergreen shrub bog association may develop, although not usually as extensively, in other areas such as along floodplains of streams (Daniel 1981). The major pocosin areas of the Carolinas and Virginia have formed in stream valleys or on broad interstream areas with restricted drainage. Paludification (bog expansion caused by a gradual rising of the water table as peat accumulates) has proceeded for sev eral thousand years in these broad inter stream areas in which natural drainage is' 12 13 blocked (Daniel 1981; Richardson et al. 1981). Richardson (1982) described the process by which these pocosins may have developed from a primary mire system (formed in a basin or depression) through a secondary mire stage in which they expanded beyond the physical boundaries of the depression because the peat acted as a water reservoir (Figure 8). Many of the North Carolina pocosins are tertiary mire systems which have developed above the physical limits of the ground waters (Richardson et al. 1981) under conditions of rainfall in excess of evaporation for several thousand years. In these wetland systems, the peat continues to act as a reservoir holding water by capillarity above the level of the groundwater. Hy- drologically, the pocosin has a perched water table elevated above that of the surrounding areas and receives water pri marily from rainfall (Richardson et al. 1981). Water moves slowly out of these raised bogs into adjacent areas. Carolina Bays No theory on the origin of Carolina bay depressions is universally accepted by scientists or laymen. The earliest pub lished theory (Tourney 1848) was that springs rising to the surface of a sandy plain formed circular lakes. Glenn (1895) suggested that the depressions were formed when coastal sandbars built up across the mouths of shallow embayments. Although the rounded contours of Carolina bays were noted in these early descriptive accounts, their abundance, elliptical shape, and parallel alignment were not recognized until aerial photographic surveys were made of the southeastern Coastal Plain in the 1930's. Melton and Schriever (1933a,b) noted the uniform shape and consistent direc tional alignments of the depressions and proposed the captivating hypothesis that they are the result of an ancient meteor shower striking the earth at an oblique angle. Prouty (1952) supported this hypothesis with explanations that the shallowness and shape of such depressions could be accounted for by shock waves from a swarm of meteors crashing into sandy, uncompacted coastal plain soils. An argument that meteorite fragments have not been found associated with any Caro lina bay depression (Johnson 1942b) was not considered as compelling negative evidence since a lack of fragments could be due to the low probability of finding pieces of an exploded meteorite (MacCarthy 1937; Prouty 1952) or due to a non-metal lic meteor swarm (Sharitz and Gibbons 1982). In rebuttal to this early extrater restrial theory of origin, other theories followed which implicated wind and wave action (Cooke 1940, 1943a,b; Johnson 1944a, b; Odum 1952; Thorn 1970; Whitehead 1973; Bliley and Pettry 1979; Kaczorowski 1977); dissolution of substrate minerals in solution pits (Smith 1931; Johnson 1942b); or a combination of factors (John son 1942b, 1944a,b; Whitehead 1981). More imaginative hypotheses regarding the ori gin of Carolina bays include the formation of pools by large schools of spawning fish (Grant 1945b), melting icebergs (Kelly and Dachille 1953), collision of the earth with anti-matter (Baxter and Atkins 1976), or launching sites for extraterrestrial spacecraft (see Justis 1974). In support of the wind and wave action theory, perhaps the strongest chal lenge to the meteor theory, Kaczorowski (1977) compared the Carolina bays with modern analogues found in Alaska, Chile, and Texas. He proposed that oriented lakes develop in topographic depressions created by any one of several processes including those coastal, fluvial, aeolian, solutioning, glacial, or tectonic in nature. He argued that once these depres sions are formed, orientation could be a function of wind regime, perhaps accompan ied by wave action. He stated that no evidence existed to support a meteor ori gin for the initial Carolina bay depres sions. Much disagreement also exists regard ing the age of Carolina bays, although they are generally accepted as being pre- Holocene by most authorities (Schalles 1979). Wells and Boyce (1953) estimated the age of Carolina bays as 250,000 years B.P. Other estimates range from 10,000 to 100,000 years B.P. From a study of pollen profiles, Whitehead (1973) suggested that the oldest sediments were formed about 100,000 years ago. He later stated that there were at least two time periods when bays were formed (Whitehead 1981). Some bays that occur on the lower Coastal Plain terraces are considered by Thorn (1970) to be younger than those on the middle Coastal Plain, also an hypothesis requir ing an explanation that allows for multi- temporal formation. BOREAL FOREST In conclusion, authorities do not agree on the age (within the 10,000 to 250,000 year limits), concurrency of formation, or mechanism of formation of Carolina bays. Disagreement also still exists about whether one of the processes described by Kaczorowski (1977) or a meteor shower created the initial depres sions. STREAM DRAINAGES DEVELOPMENT OF BOTTOMLAND FLOODPLAIN FOREST PEAT FORMATION "SHORT" POCOSIN SUBMERGED AQUATIC VEGETATION "TALL" POCOSIN 15,000-10.000 years B.P. Late Wisconsin Ice Age; low sea levels and complex stream drainage patterns on the Coastal Plain and the exposed Continental Shelf. 10,000-5,000 years B.P. Continued rise in sea levels; raised water tables; decline in stream velocities; blocked (debris clogged) stream drainage; growth of aquatic vegetation; buildup of sediments and organic material to form peat Up to Present Continued buildup of peat with increased water retention and perched water table; expansion of bogs beyond physical limits of stream depression; development of shrub bog community; periodic fires PEAT POND FORMED FROM PEAT FIRE PERCHED WATER TABLE Figure 8. Conceptual model of one proposed means of pocosin formation and development in flat interstream areas of lower Coastal Plain terraces. 14 15 CHAPTER 2 PHYSICAL AND CHEMICAL CHARACTERISTICS 2.1 SIZE AND MORPHOLOGY OF COMMUNITY TYPES Pocosins Pocosins have no characteristic size or shape. In many instances well-defined boundaries are not apparent as the pocosin shrub bog habitat grades into other vege- tationally related communities. A pocosin that would be a recognizable soil and veg etation community unit could conceivably be smaller than an acre or large enough to encompass thousands of contiguous acres. The largest identifiable pocosins occur in eastern North Carolina where 281,000 ha (695,000 acres) were recognized as undis turbed in 1979 (Richardson et al. 1981). Pocosins show no orientational aspects in regard to other topographic features other than location between old or active stream systems in many instances. Carolina Bays Carolina bays may range in length from 50 m (164 ft) to 8 km (5 mi). Lake Waccamaw in North Carolina, perhaps the largest, is 4.8 x 8 km (3 x 5 mi ; Frey 1949). Carolina bays can be readily dis tinguished from other types of depressions on the southeastern Coastal Plain by a unique suite of characteristics (Fig ure 9). These include generally shallow depth, an ovate shape with the narrow end pointed in a southeasterly direction, and an orientation in which the long axis is in a northwest to southeast direction so that Carolina bays are essentially paral lel (Prouty 1952). In most instances a low sandy rim borders each bay and is usu ally most pronounced on the southeastern margin of the ellipse. Although some authors (e.g., Melton and Schriever 1933a, b) emphasized the consistent paral lelism of the long axis of Carolina bays, Johnson (1942a) strongly challenged this concept. He reported that although the predominant long axis orientation was northwest-southeast, the range of direc tional deviation was high and varied geo graphically. Bays that he measured in Georgia and southern South Carolina were oriented on the average along a S 20°E (= N 20°W - S 20°E) direction. The majority ranged from S 10°E to S 30°E, but a few extreme examples were oriented as westerly as S 26°W and as easterly as S 56°E. A 'large sample of Carolina bays measured in North Carolina and northern South Carolina averaged S 45°E and ranged from N-S to S 67°E (Johnson 1942a). Deviation from pre cise parallelism is a factor to be consid ered in a discussion of the geological ori gin of Carolina bays, but is of no conse quence from an ecological standpoint. The basic ovate shape and shallow basin are always maintained and are the dominant physical features of ecological impor tance. 2.2 SUBSTRATE CONDITIONS Pocosins Both very poorly drained mineral soils and organic mucks and peats charac terize areas of pocosin vegetation (Barnes 1981; Gilliam and Skaggs 1981). Barnes (1981) described the mineral subsoil of these wet coastal plain soils as consist ing of layers of marine sediments varying in texture from heavy clays to sands. Clay layers permit the ponding of water at early stages ( of pocosin development and therefore can be an important soil fea ture. The shallow water table has pre vented the development of a conventional soil profile typically formed by weather ing and^ leaching processes. The pH of these pocosin soils is low. The pH of the organic horizons is commonly between 3.5 and 4.1, surface mineral soils average 0.3 watei ion« lttent egi 0 r u £ •> o S I« ,f 5S. 1 11 m •o i cd 5 u Ü H! ^ ? *• SÎI "5 S to o o> o •o CO o o. o (0 « o o CO u 'S» o o & o O» •o o CÔ o "5 _o a o . *s ~ dt *ö m E i* nu s*- l Illl o u >Zl 16 17 to 0.4 pH units higher than organic soils, and mineral subsoils frequently range between 4.1 and 4.7 in pH (Barnes 1981). Although as many as 40 different soils may be recognized in the region of the northern North Carolina pocosins (Gil lian and Skaggs 1981), three major edaphic (soil) groups generally characterize these systems. These are (1) mineral soil-with an organic epipedon (or high organic mat ter surface horizon) that does not extend deep enough ( < 40 cm or 16 inches) for the soils to be classified as organic, (2) shallow organic soils with a high organic surface extending downward 40 to 130 cm (approximately 16 to 50 inches), and (3) deep colloidal organic soils in which the organic matter horizons extend deep into the soil profile ( > 130 cm or 51 inches). These deep organic soils frequently con tain large amounts of buried wood. Jones (1981) characterized pocosin soils from 13 sites in South Carolina as having an ex tremely high organic content that gener ally extended deeper than 40 cm or 16 inches (Table 1). Although the water table is high and the soils may frequently be saturated, pocosins occasionally become dry enough to burn and some of the organic surface may be lost in combustion. Soils information for pocosins in North Carolina is provided by Lilly (1981a). In a study of the distribution and relationships of plant communities of the Green Swamp in North Carolina, a major portion of which is characterized by poco sin vegetation (see Chapter 3), Kologiski (1977) described the soils of this area (Figure 10) and provided maps derived from Table 1. Substrate characteristics of 13 pocosins in the Coastal Plain of South Carolina (Jones 1981). Substrate characteristics Range Organic matter (Ï) Organic surface depth (cm) Texture": Sand (t) S1lt (I) Clay (%) "Measured only 1n nan-organic soils 39.2 >40.0 80.6 10.4 9.0 (6 of the 8.0 - 25.3 - 63.8 - 7.6 - 2.7 - 13 sites). 94.9 >100.0 89.8 17.6 18.6 various sources. He reported the follow ing Coastal Plain soil series to be the major ones underlying the pocosin and re lated habitats. Organic Soils: Four major organic soils series are represented, grouped into two mapping units (Figure 10). They differ chiefly in depth, permeability, and drainage charac teristics. Dare Dorovan Series. These are very deep, very poorly drained and slowly per meable soils formed from the remains of swanp vegetation. The water table is at or near the surface most of the year, and the soils are extremely acid. Dorovan soils appear to frequently extend deeper than those of the Dare Series. Dare and Dorovan soils characterize the major areas of pocosin and bay forest vegetation in the Green Swanp (Kologiski 1977). Pamlico-Ponzer Series. These are moderatelydeep,very poorly drained, slowly or moderately permeable soils formed by organic deposits over marine sediments. They frequently occur in de pressions, and the water table is at or near the surface 6 to 12 months of the year. Panlico and Ponzer soils also under lie pocosin shrub communities in the Green Swamp. Mineral Soils: Kologiski identified seven minera soils in the Green Swamp (Pantego, Rains, Lynchburg, Wrightsboro, Foreston, Leon, and Torhunta), all of which are deep, poorly to moderately drained, and usually moderately permeable. However, only the Torhunta series is mapped as occurring ex tensively in the pocosin areas of the Green Swamp. Like the organic soils, Tor hunta soils are1 very poorly drained, with the water table at or near the surface 2 to 6 months of the year. ^ Despite high levels of organic mat ter, pocosin soils are deficient in avail able nutrients (Richardson 1982). The anaerobic conditions resulting from the long hydroperiods and shallow water table and the acidity of the peats preserve the organic constituents (Maki 1974). For DARE-DOROVAN SERIES m® PANTEGO SERIES | LYNCHBURG SERIES LEON SERIES I RAINS SERIES ! PAMLICO-PONZER SERIES t^^ TORHUNTA SERIES i^FORESTON-WRIGHTSBORO SERIES 18 Figure 10. Soil types in North Carolina's Qreen Swamp pocosin (based on Kologiski 1977X as redrawn by the U.S. Department of the Interior, National Park Service 1979). i 19 example, Barnes (1981) cited studies which indicate that although nitrogen levels are high, nore than 70% of the total nitrogen may be in forms (such as fulvic or humic acids) unavailable to plants. Likewise, phosphorus, generally present in the or ganic form in pocosin soils, may have low availability. Even copper may be defi cient (Barnes 1981). Jnus, on these raised organic soils precipitation is the chief external source of plant nutrients (Richardson 1982). These wetlands may therefore be considered ombrotrophic3 be cause their waters are low in available nutrients. Carolina Bays Carolina bays apparently have no con sistent relationship to sub-surface strata types. Both Thorn (1970) and Gamble et al. (1977), however, have reported that bays seem to be restricted to sandy surface deposits. The characteristic sand rim is extensive enough in some instances to make sand quarrying a profitable venture. Other than this association with sandy substrates, no consistent relationship with particular geological formations or topography in the Coastal Plain is appar ent (Prouty 1952; Kaczorowski 1977). Schalles (1979) described the upper sediments of Thunder Bay (Savannah River Plant, South Carolina) as sandy loam. The presence of 11% "charcoal fragments" in the upper soil layer results from the burning of a peat-type material. Schalles further reported the presence of an "im pervious lens" of clay of unknown thick ness about 20 to 30 cm (8 to 12 inches) below the upper sediments. This near- surface hardpan, composed of clay or a sand-iron-humate complex, may result in a perched surface water table (Schalles 1979). In perhaps the earliest report of the substrata of Caroline Bays (Glenn 1895), a similar clay layer up to 8 m (25 ft) thick was described beneath the sand layer of the bays around Darlington, South Caro lina. Likewise, Bryant and McCracken In ombrotrophic ecosystems most or all of the water and nutrients come from precipi tation rather than from other sources such as ground water or stream flow. (1964) reported that surficial sands over laid micaceous clays beneath 15 Carolina bays that they examined in Scotland Coun ty, North Carolina. In contrast, Bliley and Pettry (1979) reported sand to be the dominant soil type of surface and substra ta soils of Carolina bays on the Eastern Shore of Virginia. Carolina bays undisturbed by burning or land management practices commonly have organic surface horizons overlying the sand and clay layers. Jones (1981) de scribed the substrate characteristics of five bays in South Carolina (Table 2), each of which had more than 30 cm (12 inches) of peat or highly organic soil. In addition, Ingram and Otte (1981b) indi cated that many of the larger bays in eastern North Carolina contain high qual ity peat up to 4.6 m (15 ft) thick which might be of commercial value. 2.3 HYDROLOGIC CHARACTERISTICS Pocosins: Uater Quality, Storage, andjtel ease Hydrological fluxes in pocosins are influenced by four input-output events. Precipitation is normally the exclusive input source of water and must ultimately be equalled by the three outputs. Of these, evapotranspiration and surface run off are the primary routes of departure of water from pocosin systems (Figure 11), and groundwater discharge (the sub-surface loss of stored water within the pocosin soils) is the least significant. Although the pocosin system is not hydrologically complex, the difficulties inherent in pre cise measurement of the output events in Table 2. Substrate characteristics of five Carolina bays In northeastern South Carolina (Jones 1981). Plant cormunlty type Pocosin Pocosin Pocosin Pocosin . Bay Forest 'Measured only 1n / Organic natter (« 7*.5 74.8 29.5 12.7 14.8 non-organic Organic surface depth (cm) > 100.0 >40.0 > 100.0 33.9 x 38-9 soils. Texture' Sand S1H Clay \ t * / - . ~ \ 63.8 17.6 18.6 73.3 9.1 17.6 such geographically extensive systems have resulted in few thorough studies of the hydrodynamics of natural pocosins. Because pocosins do not drain effec tively, groundwater discharge has the least effect on annual water flux. In the Albemarle-Pamlico peninsula, which com prises extensive pocosin habitat, ground- water discharges averaged less than 1.3 cm/year (Heath 1975), equivalent to 130,000 1/ha (1842 ft3/acre), and were as sumed by Brinson (1980) to be similar to the Croatan National Forest. Daniels etal. (1977) also reported that ground- water discharge was an insignificant pro portion of the water flux in the Hofnann Forest of North Carolina. Overland runoff in the Croatan was calculated by Brinson (1980) to be approximately 52 cm (5.2 x 106 1/ha or 73,680 ft3/acre) on the basis of a regional precipitation of 144 cm/year (57 inches/year) and cumulative evapo transpi ration estimated at 91 cm/year (9.1 x 106 1/ha or 128,940 ft3/acre). The relative contributions of transpira tion and evaporation in pocosins are unknown, although Richardson (1982) re ported that 60% to 70% of the water output may be through evapotranspiration during the summer and fall. Runoff becomes more important during the winter and spring because of increased precipitation. Quan titative information regarding the role of evapotranspiration would be a useful addi tion to our knowledge and understanding of the function of these systems. Under natural conditions the surface runoff from pocosins surrounding Albemarle and Pamlico Sounds and elsewhere is as sheet flow in response to precipitation events. The input into estuaries or other receiving bodies of water occurs several days after a rain and is spread over wide areas rather than being confined to a few point locations (Ash et al., in press; Copeland and Hodson 1982). The widespread installation of drain age ditches for land management has altered the hydrology of pocosins. Drain age ditches lower the water table to some extent, particularly in their immediate vicinity, and significantly affect surface runoff (Ash et al., in press). Runoff is greater than normal especially during periods of heavy precipitation and high water tables, conditions occurring most frequently in pocosin areas during winter and spring (Ash et al., in press). The increased 'runoff rates in drainage ditch 10 i 9 8 7 6 oo 0.6 0.7L • 1 Changes in monthly mean water levels due to temperature (after adjustments for precipitation) over the 5-year period. Figure 12. Water level changes In two Carolina bays (Savannah River Plant. SC) as inf uenced by prec pftation and temperature. obtaining this vital information will be critical to understanding the hydrodynam ics of these systems. The data for Ellenton Bay support a hypothesis that rainfall raises water lev el proportionally to the amount of rain fall, whereas water level is lowered as a consequence of evapotranspiration. Evapo rative water loss is, as expected, greater at high temperatures (and therefore, dur ing warm seasons) than at low ones. Evap oration rates would also be affected by wind and by relative humidity, which are unmeasured variables at Ellenton Bay. In addition, transpiration rates in bays with heavy aquatic vegetation might cause sig nificant changes in water level during the growing season. Soil permeability and the surrounding watershed would also influence water collection and retention. Although groundwater recharge (Schalles 1979) has been considered as a potentially important factor in changing water levels in certain Carolina bays, there is little evidence to support a general hypothesis that the water table is influential in affecting water level fluctuations in Carolina bays. This limited information for Ellenton Bay is the only published data available to address the influence of environmental factors on the fluctuations of water lev els in Carolina bays. Long-term measure ments of such basic phenomena as local precipitation, evapotranspiration rates, groundwater levels, soil permeability, and local topography and their relations to changes in water level would be valuable. Dynamic habitats such as these can support only species with effective adaptations to cope with such fluctuating conditions. CHAPTER 3 BIOLOGICAL FEATURES 3.1 PLANT COMMUNITY COMPOSITION Pocosins Few studies provide more than a brief or superficial description of pocosin veg etation and fauna. The apparent lack of interest in pocosin ecosystems is no doubt due in part to their perceived low commer cial value and the difficulty involved in working in these habitats. As Christensen et al. (1981) stated, "...their limited economic value, impenetrable character, and alleged dense populations of venomous or otherwise malevolent critters have suc cessfully repelled ecologists for the past fifty years." In addition, disagreement regarding what actually qualifies as a pocosin and how the boundaries of »these ecosystems are defined, coupled with the fact that many of their characteristic species occur in other wooded wetland sys tems, has hindered or confused ecological description. There is limited information on species composition, productivity, and successional development of pocosins and their relationships with other Coastal Plain ecosystems. Developmental history of pocosin com munities.Developmental historyofthe vegetation of the coastal area of the Mid- Atlantic States has been described by sev eral investigators (e.g., Buell 1945; Frey 1951b, 1953, 1955b; Whitehead 1963, 1964, 1981), based primarily upon examination of pollen profiles obtained from soi cores. Although there exists no complete descrip tion of the vegetational history specific to pocosins, the development of this flora can be inferred from these studies and a more recent one by Otte (1981), which used samples taken from Carolina bay and poco sin sediments. Frey (1951b, 1953, 1955b) sampled cores from a series of Carolina bays and_ described a pine-spruce forest that exist ed during the period of Wisconsin glacia tion. Whitehead (1964) reported a greater dominance of pine during this period with some boreal species occurring primarily on more mesic sites. Late-glacial (about 10,000 to 15,000 B.P.) forests dominated by oak, hickory, hemlock, and beech re placed the pine and spruce forests as the glaciers retreated and the climate warmed. More recent post-glacial changes until the present time have included the gradual decrease in oak-hickory forests, develop ment of southern pine forests, and an increase in cypress-gum dominated vegeta tion in wetter sites. The development of shrub bog vegeta tion in pocosin areas is difficult to trace. Ingram and Otte (1981b) reported that peat began to build up about 8,000 to 10,000 years ago in the dissected depres sions of the outer Coastal Plain, often building up to form broad, dome-shaped surfaces. As noted earlier, carbon-14 dating of sediments from the' Great Dismal Swamp and the Chesapeake Bay indicates that deposition of organic clays and peat accumulation in these areas began between 10,340 ± 130 and 8,135 ± 160 years B.P. (Daniel 1981). These sediments contained late-glacial pine and spruce pollen or oak-hickory pollen. However, older peat samples (15,280 ± 200 years B.P.) contain ing abundant spruce pollen from the mid- glacial period have been recovered from one area of the Chesapeake Bay (Harrison et al. 1965). Furthermore, Richardson (1982) noted that radiocarbon dating of other areas of the Dismal Swamp indicates that much of the peat may be less than 3,500 years old. He interpreted these various ages along with information from pollen profiles, the presence of charcoal in the peat, and historic climatic changes to indicate a dynamic developmental his tory of pocosin substrates that includes 26 27 r fluctuations in oxidation and in the rates of peat accumulation and the occurrence of extensive fires. Peat accumulation, fire, nutrient levels, hydroperiod, human use, and other ecological and environmental factors have contributed to the development of the present pocosin ecosystems. Opinions of investigators differ about which of these factors are primarily responsible for the establishment and maintenance of pocosin communities. From an extensive survey of North Carolina pocosins, Otte (1981) pro posed a pattern of pocosin community de velopment based upon peat profile analy sis. He believes that most pocosins began as marsh systems dominated by aquatic mac- rophytes and grasses, succeeded to cypress and Atlantic white cedar (Chamaecyparis thyoides) forests, and finaîTyto shrub bog pocosins. He reported that most of the pocosin ecosystems appear to have de veloped the evergreen shrub-dominated com munity relatively recently (in the last few thousand years) in terms of the over all age of the wetland. Only the Croatan National Forest pocosins (Figure 13) and southern Dare County pocosins appear to be relatively old (Otte 1981). The substrates of the Croatan pocosin consist of 0.6 to 1.2 m (2 to 4 ft) of white cedar peat overlain with pocosin peat 1.2 to 1.5 m (4 to 5 ft) thick (Figure 13). Otte noted, however, that within the pocosin peat are patches of marsh peat, indicating local wetter conditions and perhaps the sites of peat burns that left shallow open pools where marsh vegetation developed. CHOATAN NATIONAL FOREST PROFILES THROUGH MAJOR PEAT BOG E3 HUMIC POCOSIN PEAT g FIBROUS WHITE CEDAR PEAT E3 PEATY SAND AND SAND B. W. Wells (Wells and Whitford 1976) described the poorly drained interstream areas of the Coastal Plain as historically being covered by broadleaf swamp forests dominated by black gum (Nyssa). sweet gum (Li'qui'dambar), and naple (Acer). Appar ently, they dried out frequently enough for tree seeds to germinate and seedlings to become established. Wells further re ported that fires by Indians and later by white settlers began to change these hard wood swamp forests into shrub bogs, or po cosins. He believed that the frequency of fire played a major role in the develop ment of pocosin vegetation and in the relationship between pocosins and other plant associations. For example, if the hardwood swamps were burned as frequently as every decade, the deciduous forest dis appeared or became dominated by pond pine (Pinus serotina) and southern cane (Arund- inaria gigantea). When burning was even frequent, fire resistant shrubs or shrubby trees such as sweet bay, (Magnolia yirgiana), red bay (Persea borbom'a), and' leucothoe (Leucothoe spp.) became domi nant, along with greenbrier. All of these species have the' ability to sprout from stumps or roots following burning, and they form virtually impenetrable jungles. If these pocosin communities were burned annually, the shrubs practically disap peared and were replaced by grasses, sedges, and herbs. If fire frequency was reduced, these grassy habitats reverted to shrubby pocosin communities. Wells and Whitford (1976) noted that if fire was eliminated altogether, savannas and shrub bogs returned to swamp forests, although 0.5 1 MILE -OFT -2 -4 Figure 13. Representative cross section through the Croatan National Forest pocosin sub strates (from Otte 1981). 28 Otte (1981) suggested that pocosin on deep peat will remain unless the peat is se verely burned. Fire and other disturbances have played a major role in development of the pocosin vegetation of the Green Swamp in North Carolina (Kologiski 1977). Kologiski noted early reports that much of the area was once dominated by Atlantic white cedar swamps and extensive cypress-gum swamps. Logs buried under several meters of peat are all that remain of the white cedar forests believed to have been destroyed by fire. Recent surveys of the area revealed remnants of the cypress-gum forests that were heavily logged in the 1800's and early 1900's (Kologiski 1977). Characterization of pocosin vegeta tion.Early accounts of pocosin vegeta- tion, such as those of Kerr (1875) and Harper (1907), were primarily lists of plant species and brief descriptions. Wells (1928) included a description of pocosin or bay vegetation in his charac terization of coastal plain plant commu nities and later provided some quantita tive data on the pocosin vegetation of Holly Shelter Wildlife Management Area (Wells 1946). Other early studies (e.g., Buell 1939a, b, 1945, 1946a, b; Penfound 1952) added limited information to the characterization of pocosin habitats. More recently, Woodwell (1956, 1958), Kologiski (1977), Christensen (1979), Christensen et al. (1981), Otte (1981), and Jones (1981) have concentrated exten sive sampling and analysis on this vege tation type. Most of the information regarding pocosin vegetation that is presented in this community profile is taken from the work of these researchers. Throughout this report, the use of plant names follows Radford et al. (1968). The typical pocosin or shrub bog vegetation is characterized by a shrub understory with scattered emergent trees (commonly pond pine). The height of the shrub cover usually ranges from 0.5 m (1.5 ft) to 4 m (13 ft). If the woody vegetation (tree component) is less than 6 m (19.5 ft) high (scrub-shrub), it is generally called short pocosin; if greater than 6 m high (forested), it is considered to be tall pocosin (Figure 14), although these size designations differ among the investigators (e.g., Otte 1981). Pocosin communities are commonly termed evergreen shrub bogs; however, many of the charac teristic pocosin species are partially deciduous (e.g., titi [Cyril!a. racemi- flora]) or wholly deciduoTfs (e.g., sweet fepperbush [Clethra alm'folia], fetterbush Lyoni a lucidaj, zenobia [Zenobia pulver- ulenta], blueberry CVaccinium spp.], huckleberry [Gaylussacia frondosa]). Some pocosin species, such as titi, may tend to be deciduous in more northern pocosin com munities and to retain their leaves in more southern habitats. Deciduous species may even dominate in some of the shrub bogs (as may tree species rather than shrubs). In addition to pond pine, other pine species, especially loblolly (£. taeda) and longleaf (P_. palustris), may occur in the better drained areas. In some pocosins, Atlantic white cedar and also cypress (Taxodium spp.) and gum (Nyssa spp.) may be found. Hardwood trees, especially sweet bay, loblloly bay (Gprdonia lasianthus). and red maple (Acer rubrum) are common in many pocosin areas, particularly on less peaty sites. One of the few comprehensive descrip tions of pocosin and related wetland com munity types has been provided by Kologi ski (1977) in an extensive survey of the Green Swamp in Brunswick County, North Carolina. He described the Green Swamp vegetation as a complex continuum of popu lations arranged according to soil, mois ture, and disturbance factors (Figure 15). By using several ordination techniques designed to demonstrate relationships among samples, Kologiski examined data from 220 stands, including the evergreen shrub pocosin community as well as related communities. Although he reported much overlap between vegetation types, he iden tified discrete vegetational units, which he organized into a hierarchial system of classification adapted from the natural areas classification system of Radford (1977). Using this classification, Kolo giski (1977) described five vegetational systems in the Green Swamp, based upon species composition and growth form, which he arranged in a successional sequence from a marsh grass pioneer community to a lowland forest. Within these systems, he separated nine community classes according to the dominant canopy, shrub and herba ceous understory species. 29 i I [EXPERIMENTAL TREE PLANTING CONIFER-HARDWOOD POCOSIN \%& BAY FOREST fa i i ' (^ATLANTIC WHITE CEDAR FOREST | PINE SAVANNA PINE-ERICALEAN POCOSIN I MIXED WHITE CEDAR AND BAY FOREST Low or short pocosin habitat, near the center of Angola Bay. Pender County, NC \:< v N t'- .»• High or tall pocosin habitat. Holly Shelter Wildlife Management Area. Pender County, NC (with evidence of a fire) * Figure 14. Comparison of two types of pocosin habitats. (Photographs by Charles B. McDonald, East Carolina University, Greenville, NCJ 30 Figure 15. Vegetation types hi Green ^wamp, NC (based on Kologlski 1977. as redrawn by the Department of the Interior. National Park Service 1979). 31 Only one of the five vegetational systems in the Green Swamp (the "wet scrub-shrub system," as described by Kologiski) can be considered true "poco- sin" according to the definition followed in this community profile. The wet scrub- shrub system contains the pocosin commun ity cover class that includes those com munities dominated by evergreen shrub and tree species characteristic of pocosins (Table 5a). Other vegetation systems of the Green Swamp (marsh grass; low wood land, which contains the pine savanna cover class; lowland gymnosperm including cedar bogs; and lowland angiosperm con taining the evergreen bay and deciduous forests) represent peripheral and/or suc- cessionally related habitats (Table 5b). The successional relationships among these vegetation types are still a matter of speculation, and the suitability of Kologiski's classification system outside of the Green Swamp has yet to be deter mined (Christensen et al. 1981). Further more, portions of the Green Swamp have been affected by land management practices since Kologiski's study, so that his map of the vegetation (Figure 15) is now out of date. Nevertheless, because it is one of the most complete vegetational studies, Kologiski's description and community classification are summarized here to pro vide an example of an interstream pocosin and related plant communities in North Carolina. Kologiski described the wet scrub- shrub system (pocosin community cover class) as the dominant vegetation of the Green Swamp. According to Cowardin et al. (1979), who developed the system of class ification of wetlands and deepwater habi tats for the U. S. Fish and Wildlife Ser vice, the class scrub-shrub includes areas of woody vegetation generally less than 6 m (19.5 ft) tall. Vegetation in this class includes shrubs and trees that are small or stunted because of environmental conditions (Figure 16). The pocosin community of the Green Swamp is a complex unit containing two community classes (pine-ericalean and conifer-hardwood), each with two or more community types (Table 5a and Figure 17a). Distinct boundaries between community types are often difficult to determine. Kologiski indicated, however, several com munities that differ primarily because of the length of hydroperiod and time since the last fire. The Pine-Erioalean (pine and heath shrub) Community Class generally develops on deep to intermediate organic soils that are exposed to long hydroperiods and fre quent fire (Table 5a). There are three community types: (1) Pond pine (Pinus serotina) canopy with titi (Cyrilla racemiflora) and zeno- bia (Zenobia pulverulenta)shrubs. This vegetation usually occurs on deep organic soils with water at or near the surface throughout the year. Although the commun ity is dominated by shrubs, widely spaced pond pines may form an open canopy. Growth of the pines is slow, and they frequently exhibit a gnarled, twisted, and stunted -form. Their average height may range from 2 m (6 ft) to 12 m (39 ft). Dominant shrubs are titi and zenobia, both of which may exhibit greater than 75% cover. Fetterbush is abundant, but it usually has a lower cover value. The height of the shrub layer ranges between 0.5 m (1.5 ft) and 2 m (6.5 ft). Other shrubs as well as herbaceous species such as broomsedge (Andropogon virgim'cus) occur, and greenbrier drapes over and twines through the shrubs. (2) Pond pine (Pinus serotina) and loblolly bay (Gordonia lasianthus) canopy with fetterbusü(Lyonia lucida) shrubs. This community occurs on slightly drier elevated (approximately 0.5 m or 1.5 ft) areas within the previous community type. These elevated areas resemble islands up to or greater than 100 m2 (more than 1000 ft2) and are most likely formed by an accumulation of sphagnum and litter around the stumps or bases of pond pine trees. In addition to the pond pine, loblolly bay, and fetterbush, shrubs that may form an almost impenetrable thicketxinclude sweet gall berry (Ilex coriacea). bitter gall berry (K.glabra), and titi. (3) Pond pine (Pinus serotina) canopy with titi (Cyril la racemi flora) and fet terbush Sx- utaa&a Cr * till (Cyrilla racemiflora) Ct - Atlantic white cedar (Chomaecyparis thyoides) Gl = loblolly bay (Cardonia lasianthus) Ic sweet gallberry (Ilex coriacea) LI - fetterbush (Lyonio lucida) Vc = highbush blueberry (Vaccinium corymbosum) Me Pp lg Gf As Aq Ic Mh Ns Mv Cr Ar H I O PIHUSIArislida b. P NE SAVANNA Cr titi (Cyrilla racemiflora) Ct - Atlantic white cedar (Chamaecyparis Ihyoides) Cf - huckleberry (Caylussacia frondosa) Gl = loblolly bay (Gordonia lasianthus) Ic sweet gollberry (Ilex coriacea) lern- dahoon (Ilex cassine var. myrlifolia) Ig = bitter gallberry (Ilex glabra} LI fetterbush (Lyonia lucida) Mv sweet bay (Magnolia virginiana) Pb - red bay (Persea borboniol Ps = pond pine (Pinus serotina} Ta pond cypress (Taxodiutn oscendens) Va = blueberry (Vaccinium atrococcuml Wv = chn'n fern (Hoodwardia virgintca) CHAMAECYPARIS/tyonia-/fcx c. CEDAR BOG Ar red maple (Acer rub rum) Cr titi (Cyrilla racemiflora) Gf - huckleberry (Gaylussacia frondoso) Ic = sweet gallberry (Ilex coriocca) Ig bitter gallberry (Ilex globra) LI - fetterbush (Lyonla lucida) Mv = sweet bay (Magnolia virginiana) Ns - black gum (Hyssa sylvatica var. biflora) Pb - red bay (Persea borbonia) Ps - pond pine (Pinus serotina) Ta pond cypress (Taxodium ascendens) Vc highbush blueberry (Vaccinium corymbosum) Wv chain-fern (Woadwardia virginico) Wv Ct GIVa Ps lern Mv Cr GfTalg Pb LI PERSEA PINUS-GORDONIA CHAMAECYPARIS-MAGNOLIA/Cyr/Ho-Lyon/o Ilex d. EVERGREEN BAY FOREST TAXODIUM-ACER-NYSSA/CyriHo Lyonia-llex e. DECIDUOUS FOREST Figure 17. Major woody plant community cover classes In Green Swamp, NO (based on Kolo- giski 1977). 38 1979; Chrlstensen et al. 1981). Using reciprocal averaging ordination to evalu ate Woodwell's (1956) classification, Christensen determined that although the three categories do not fall into discrete groups, they do tend to dominate specific parts of the ordination. Christensen et al. (1981) further attempted to relate species dominance to known environmental features including geologic type of poco- sin, peat depth, water table depth, sub strate type, and age of the community since burning. They also concluded that zenobia tends to dominate in recently dis turbed areas in which the shrub community has relatively low productivity and higher diversity, whereas titi and fetterbush occur in more productive bogs. They were unable, however, to add much additional insight about the causes of variation among pocosins. Jones (1981) described 52 lowland forests in the northern Coastal Plain of South Carolina, including 13 pocosins. Densities and basal areas of trees from a typical pocosin site (Table 6) are low in comparison with other wetland forests. Pond pine dominated these communities, with loblolly bay and pond cypress being next in density. The chief shrub was fetterbush, with greenbrier often the second most important species (Table 7). The gall berries, blueberries, wax myrtle (Myrlea cerifera). and zenobia also con- tributed significantly to the shrub cover which commonly reached or exceeded 100% ground coverage and was the highest cover age measured by Jones (1981) in any of the wetland communities. Associated communities. In addition to the pocosin community, Kologiski (1977) described four peripheral and perhaps re lated community cover classes in the Green Swamp: sedge bog (representing the marsh grass system), pine savanna (low wood land system), cedar bog (lowland gymno- sperm forest), and bay forest (lowland angiosperm forest; Table 5b). Each of these vegetation systems will be briefly characterized. Table 6. Density and basal area of trees in a pocosin in South Carol'na (from Jones 1981). Species Density (stems/ha) Basal area (n /ha) jMnus serotina (pond pine) 538 Gordonia lasianthus (loblolly bay) 125 Taxodium ascendens (pond cypress) 103 Nyssa sylvatica var. biflora (black gum) 77 Persea borbonia (red bay) 18 Magnolia vlrqini'ana (sweet bay) 7 Myrica cerifera (wax myrtle) 11 Acer rubrum (red maple) 7 _Ilex cassine (dahoon) 4 Total 890 8.70 0.88 1.34 0.42 0.06 0.02 0.04 0.07 0.01 11.54 O 39 Table 7. Density and transect cover of shrubs, woody vines, and tree seedlings In a South Caro lina pocosln (from Jones 1981). Species Lyorn'a lucida (fetterbush) Smilax spp. (greenbrier) II jx glabra (bitter gall berry) Vaccinium spp. (blueberry) Persea borbonia (red bay) Magnolia virginiana (sweet bay) Myrica cerifera (wax myrtle) Gaylussacia spp. (huckleberry) Ilex coriacea (sweet gall berry) Sorbus arbutlfolia (chokeberry) Gordom'a lasianthus (loblolly bay) Pi nus seroti'na (pond pine) Rhus radicans (poison ivy) Ilex cassine (dahoon) Nyssa sylvatica var. biflora , (black gum) Lyoni'a ligustrina (fetterbush) Total Density (stems/ha) 10144 3480 2016 1401 1231 594 446 446 , 403 191 255 255 85 64 42 21 21074 Transect" cover (cm/m) 45.12 11.08 6.67 9.12 7.79 6.25 2.92 0.58 4.50 3.00 2.46 1.12 0.29 1.42 1.42 , <0.01 103.74 Sedge bog. This is the most hydric community type included in Kologiski's classification of the Green Swamp vegeta tion. The community type represented in this area is dominated by the sedge Carex walteriana and occupies shallow depres sions in organic soils that contain stand ing water during most of the year. It is therefore "wetter" than the pocosin shrub community. Such depressions are frequently formed by fires burning into the peat dur ing periods of low water. Sedges, especially £. walteriana. are usually the first plants to invade the wetter sections of a pocosin after fire or other major disturbances. These sedges often form dense stands with almost 100% cover, although other herbaceous as well as shrub species may be found in this com munity type. After the depressions begin to fill, zenobia and then titi invade, and the community becomes shrub dominated. Pine savanna. This vegetative commu nity cover class has a widely spaced can opy of pines with an understory ranging from predominantly grasses to a mixture of grasses, shrubs, and ferns (Figure 17b). According to Kologiski (1977), the savanna communities of the Green Swamp are charac terized by mineral soils, short hydroper- iods, and frequent fires. The soils are usually well drained; however, because of a perched water table, water is within a meter (3 ft) of the surface most of the year. Although the moisture gradient from pocosin to pine savanna is generally grad ual , the vegetational ecotone may be sharp (Christensen et al. 1981), largely because of the higher frequency of fire in savanna areas. Three types of pine savanna occur in the Green Swamp: (1) Longleaf pine (Pinus palustris) canopy with wire grass (Aristida strieta) and sedges (Rhynchospora spp.) as ground cover. This savanna type occurs on min eral soils that are usually well drained, although in the more hydric areas, water roay be at or near the surface during the rainy season. Pond pine is the chief can opy species and wire grass dominates the ground cover. Several species of sedge roay share the dominance with wire grass. (2) Pond pine (Pinus serotina) canopy with wire grass (Aristida stricta) and sedges (Rhynchospora spp.) as ground cover. In the more hydric savannas, pond pine becomes the canopy dominant. A simi lar community with switchcane (Arundinaria gigantea) as the ground cover develops in response to frequent burning, although it is not common in the Green Swamp. (3) Longleaf pine (Pinus palustris) canopy with huckleberry (Gay!us.sacia fron- dosa) and bitter gal 1 berry (IIex~g1 abra) in the shrub layer. This community, which occurs on better drained mineral soils than (1) and (2), has a more closed pine canopy and a low shrub layer. Huckleberry and bitter gall berry are the most impor tant species of the latter. Other shrubs include sweet gall berry, leucothoe (Leuco- thoe axillaris), lyonia (Lyom'a man'ana). and several spp.). rica cerifera wax myrtle ( __ species of "blueberry (Vaccinium As in the Green Swamp, savannas fre quently occur in association with poco- sins. They develop .on ridges or high areas that are elevated sufficiently to prevent peat accumulation (such as the rims of Carolina bays). A difference in elevation of only a few centimeters may be sufficient to separate pine savannas from the surrounding pocosins (Ash et al., in press). Fire maintains the savannas by limit ing invasion by shrubs. Without frequent fire, the savannas will become pine- dominated forests with an evergreen shrub understory. Succession will proceed more rapidly in areas with greater surface drainage. The extent of savannas is usu ally limited. In the Green Swamp, only 93 ha (230 acres) of the 5,609 ha (13,860 acre) nature preserve is savanna (Mclver 1981). Cedav bog. Atlantic white cedar for ests are often associated with pocosins. White cedar may become established in open habitats on organic soil, especially after fires when the water table is high (Figure 17c). It commonly forms dense even-aged stands in areas of highly acidic peat and stagnant water (Dean 1969). Seedlings may become established under shrubs and parent trees, but since they require sunlight, growth is decreased once the canopy begins to close. Kologiski identified two commu nity types: 40 41 III III LUI (1) Atlantic white cedar (Chamaqcypa- ris thyoides) canopy with fetterbush (Lyonia lucida) and sweet gal 1 berry (Ilex coriacea) in the shrub layer. According to Kologiski, in the Green Swamp this type is best developed over deep organic soils that are usually wet throughout the year, although standing water is unusual. The ground is covered with a mat of white cedar leaves and other organic debris, and fallen white cedar logs and stumps are abundant. These stands commonly form a dense canopy. The understory of smaller deformed white cedars and the distinct shrub layer form an almost impenetrable thicket. The shrub layer ranges in height from 1m (3 ft) to several and is domi nated by fetterbush and sweet gall berry. Greenbrier and yellow jessamine (Gelsemium sempervirens) are important vines. The herb layer is almost absent. (2) Atlantic white cedar (Chamaecypa- ris thyoides) and loblolly pTnë(Pinus taeda) canopy with fetterbush (Lyonia lu cida) and sweet gal1 berry (Ilex coriacea) in the shrub layer. Loblolly pine is prominent in the canopy of this community, although it is never actually a codominant with white cedar. While very similar to the previous community (1), this type is usually found on shallow organic soils underlain by sandy clay loam. Successional studies (Buell and Cain 1943) indicated that burned white cedar forests typically become evergreen bay forests. These cedars have no resistance to fire, and burning usually kills all the trees in a stand. Successful regeneration following fire depends upon a store of viable seeds in the upper layers of peat (Ash et al., in press). If fires occur during extremely dry periods and burn the peat, the seed source may be eliminated. In such areas where the cedars have been destroyed completely, pocosin and bay spe cies will become dominant. Bay forest. The bay forests described by Kologiski (1977) are characterized by shallow to deep organic soils, intermedi ate to long hydroperiods, and canopies dominated by combinations of red maple, Atlantic white cedar, titi, loblolly bay, sweet bay, black gum, red bay, pond pine and pond cypress. One or all of the bay trees (sweet bay, red bay, loblolly bay) are present in both the evergreen and deciduous phases of this forest (Figures 17d and e). Community types are: (1) Sweet bay (Magnolia virginiana), red bay (Persea borbonja), and loblolly bay (Ggrdonia lasianthus) canopy with titi (CyriTTäTäcerniflora) and fetterbush (Lyonia lucida) shrubs and Virginia chain- fern(Woodwardia virginica) as ground cover (FigureTTd). This lowland ever green bay forest develops on deep organic soils that are poorly drained and have long hydroperiods. Standing water is typ ically present during part of the year and the water table is always near the sur face. The three bay species (loblolly bay, red bay, and sweet bay) dominate the canopy, which may be shared by Atlantic white cedar, titi, dahoon, pond pine, and deciduous species such as red maple, black gum, and pond cypress. The canopy is 3 to^lO m (10 to 32 ft) high, and the shrub stratum usually blends into it. Major shrubs include titi, huckleberry, fetter- bush, sweet gall berry, bitter gall berry, smooth winterberry (Ilex laevigata). dahoon, bayberry (Myrica heterophylla), swamp azalea (Rhododendron viscosum), highbush blueberry (Vaccinium atrococcum, V^. corymbosum), and zenobia. Greenbrier is abundant and Virginia chain-fern is the most important herb. Kologiski (1977) believes that in the Green Swamp, this evergreen bay forest succeeds the titi-zenobia pocosin and probably the white cedar forest (following logging). He reported that the most com mon seedlings in many of the evergreen bay forest stands were red bay, indicating eventual domination by this species. A major fire may cause this forest to revert to a pocosin or white cedar forest (with a shallow burn), a sedge bog (with a deep burn and high water table), or a deciduous bay forest (with a deep burn and temporar ily low water table). (2) Red maple (Acer rubrum). black gum (Nyssa sylvatica var. biflora), and pond cypress (Taxodium ascendens ) canopy with titi (Cyril!a racemi flora) and fet terbush (Lyonia lucida)shrubs and Vir ginia chain-fern (Woodwardia virginica) as ground cover (Figure 17e). This lowland deciduous forest xdevelops on shallow organic soils with intermediate to long hydroperiods and an absence of major fires. Standing water may be present over the hummocky substrate for at least sev eral months of the year. Most of the same species are present in both the evergreen bay and the deciduous forests and the two types blend into one another. In the Green Swamp, the dominant canopy species in the deciduous forests are red maple, black gum, and pond cypress, with frequent occurrence of red bay, pond pine, and lob lolly pine. The height of the canopy ranges between 10 and 25 m (32 to 82 ft). Although the dense understory contains a number of shrubs, titi and fetterbush are usually the dominants. Several species of greenbrier are abundant, and Virginia chain-fern is the dominant herb. Kologiski reported that the presence of canopy seedlings and saplings indicates that the lowland deciduous forest in the Green Swamp is perpetuating itself. He suggested that under existing environmen tal conditions, it can be assumed that a mature lowland deciduous forest is rela tively stable. Over time, however, espe cially if drainage occurs, the area will become dominated by more upland species. Extensive disturbance such as fire or cut ting would probably revert this type to conifer-hardwood pocosin. Only the Pine-Ericalean and the Conifer-Hardwood Community Classes as described by Kologiski (1977) in the Green Swamp typify the shrub bog definition of pocosin used in this community profile. However, the other marsh, swamp, and for est associations represent related commun ity types. A comparison of various eco logical attributes of several of these communities, based upon the work of Jones (1981), is given in Table 8. Kologiski's ordination of 220 stands sampled in ever green shrub and related communities pro vides a rough reflection of the soil mois ture gradient. Sites with relatively dry mineral soils, dominated by pond pine, wire grass, sedges, huckleberry, and bit ter gall berry, are located at one extreme of the arrangement; and sites with highly organic wet soils, dominated by Carex SPP., zenobia, and titi, are located at the other extreme. Proposed relationships between the vegetation units of the Green Swamp and environmental factors are de picted in Figure 18. General patterns of community classes as influenced by soil/ hydroperiod and fire frequency can be interpreted from this scheme. Kologiski (1977) noted that hydroperiod is probably the most important of the factors since it controls the establishment and the growth of the plants and also, to some extent, the severity of fire and its effect on the vegetation. Around lakes or ponds, or in areas with distinct drainage patterns, pocosin communities may intergrade with swamp for est vegetation. Only at their margins, however, do these upraised shrub bogs ap pear to be succeeding to swamps (Christen- sen et al. 1981). Characteristic bay for est species (cypress, black gum, and white cedar) are usually absent except in these wetter areas. At the other end of the moisture gradient, shrub bog vegetation becomes pine flatwoods and savannas domi nated primarily by loblolly and longleaf pine with a diverse herbaceous understory. Successional relationships. As noted earlier in the discussion of the histori cal development of pocosin communities, evidence from peat profiles suggests that most of these shrub bog communities devel oped in the last few thousand years. Otte (1981) reported that the pocosin peats were typically underlain by organic re mains of marsh vegetation with Atlantic white cedar and cypress common in deeper layers of the peat, especially near ancient stream channels. Paludification, or expansion of these pocosin wetlands, proceeded as a result of peat accumulation and an associated gradual rise in the water table. There are basically two theories of pocosin succession which are in sharp con trast to each other. The first, proposed by Wells (1928), assumes that the fre quency and intensity of fire controls suc- cessional development. According to this theory, short pocosin is a pioneer stage leading to bay forest as a climax. The Successional process could therefore be completed within a few hundred years if disturbance is prevented. The second theory of pocosin succession (Otte 1981K assumes that nutrient levels are the con trolling factor. According to this hypo thesis, the successional sequence is marsh —»-swamp forest——+- bay forest —^ tall pocosin—»-short pocosin. This sequence 42 43 of events may require thousands of years for the modification of the substrate and development of an upraised bog with a perched water table to occur. Relationships of pocosin communities to other wetland plant associations have been mentioned throughout the above de scriptions. A delicate balance of envir onmental factors controls these community relationships. The three major factors directly controlling the distribution of vegetation within the pocosin ecosystem are thickness of the peat, length of the hydroperiod, and frequency and severity of fire (Otte 1981). These factors are interrelated in such a complex way that an alteration of one will affect the others. Therefore, it is impossible to separate their individual effects and relative sig nificance to the maintenance and integrity of pocosins. In general, the evergreen shrub bog pocosin communities occur on the deepest peat substrates. Following an extensive survey of pocosins in North Carolina, Otte (1981) proposed that peat thickness, along with hydroperiod and associated nutrient availability, is primarily responsible for the maintenance of short versus tall Table 8. Comparison of various geological and ecological parameters of pocosins, pine savan - nas. and bay forests in South Carolina (from Jones 1981). Values represent means for all sites of each community sampled unless indicated otherwise. Parameters No. of tree species No. of shrub species Total no. of woody species Tree basal area (m2/ha) Shrub cover (cm/m) Depth of organic substrate (cm) % organic matter Mineral soil: % sand % silt % clay No. of sites sampled Pine savanna 7.7 8.2 15.9 14.5 22.6 18.0 6.5 81.2 12.8 6.0 6 Pocosin 7.9 11.3 19.2 14.3 ' s 117.2 >40.0 39. 2a 4. 80. 6a 10.4a 9.0a 13 ' 1 Bay forest 11.0 13.8 i 24.8 33.3 88.9 >40.0 53.8 59.3 31.2 9.5 6 X Measured only in non-organic s (6 of the 13 sites). z LU O 01 Ö LU ce H Z LU 03 PINE SAVANNA (GRASS UNDERSTORY) / MARSH BOG \ CONIFER-HARDWOOD PINE-ERICALEAN POCOSIN / \ DECIDUOUS BAY FOREST PINE SAVANNA (SHRUB UNDERSTORY) EVERGREEN BAY FOREST WHITE CEDAR FOREST MINERAL SHORT SOIL TYPE HYDROPERIOD ORGANIC LONG Figure 18. Proposed relationships among vegetation types, hydroperiod, and fire In pocosin habitats (based on Kologiski 1977). 45 pocosin vegetation. According_to his theory, the[deeper portions of the thicker peat substrates are always saturated with water because the water table rarely falls lower than 1.2 to 1.5 m (4 to 5 ft) below the surface. Thus the root systems of plants never reach the underlying mineral sediments and are confined to the nutrient-poor organic substrates. Such plants are therefore stunted (short poco sin). In contrast, in the shallower peats the water table frequently drops below the peat-sediment interface (Otte 1981). In this circumstance, downward-growing roots can reach the more nutrient-rich mineral sediments and growth is enhanced (tall pocosin). Furthermore, Otte suggested that the short pocosin is the only pocosin community that can be considered a true climax community. Once peat substrates become so thick as to prevent plant roots from reaching the mineral soil, the short pocosin will remain a permanent feature unless a major fire or other disturbance removes part of the peat. Pocosins typically occur in areas of relatively long hydroperiod with the water table at or near the surface for 6 to 12 months of the year. This prolonged expo sure excludes many of the bottomland hard wood species characteristic of stream floodplains and bay forests as well as the upland pines and hardwoods. Water-tolerant swamp species such as cypress and black gum are occasionally associated with poco sin communities, but seldom become domi nant, presumably because of the low nutri ent availability of the organic pocosin substrates. An important difference be tween swamps and pocosins is in the direc tion of water flow (Otte 1981). Water flows into and through swamp ecosystems, replenishing nutrients. In pocosins, the major direction of water flow is out of the ecosystem via runoff; therefore, pre cipitation is the only major source of water and nutrients. The frequency and intensity of fire also influence the vegetation of pocosins. Obviously, since the highly organic soils burn readily when dry, the potential severity of a fire is related to the depth of the water table. Following shal low peat burns that destroy surface vege tation and the surface layer of peat, but do not damage the root and rhizome mat, the original pocosin type will recover quickly (Otte 1981). A burn that destroys the rhizome and root mat will be followed by recolonization from seeds and vegeta tion growing inward from the edge of the burned area. A fire that burns the peat to a depth such that the roots of the recolonizing vegetation can more readily come in con tact with the mineral soil may permit re covery of the same species as originally present. However, because of increased nutrient availability, their growth may be enhanced (Otte 1981). A severe burn over shallow peat that removes all the organic material above the mineral sediments will probably lead to the development of a non-pocosin community. On the other hand, a severe burn in deep peat substrates during a period of low water table could open up an area that would become a lake upon return of a high water table (Otte 1981). On better-drained soils, commonly associated with slight increases in eleva tion (such as the rims of Carolina bays), frequent occurrence of fire will tend to maintain a pine savanna community. Shrubs and upland hardwoods nay become estab lished if fire is prevented. Adaptations of pocosin vegetation. Many of the characteristic pocosin species are not only tolerant of fire, but they nay also actually be dependent upon it for completion of their life cycles. Pond pine trees are resistant to fire and typically sprout from the roots as well as from epicormic buds (those along the trunk of the tree) following 'fire (Christensen et al. 1981). In addition, heat from fire stimulates opening of the cones that are serotinous (delayed in opening), some of which may remain closed after seed matura tion for up to 10 years. Such opening of the cones following fire ensures seed dispersal at a time when open areas are available for successful establishment of seedlings. Many of the pocosin shrubs may also sprout vigorously from their roots after being burned. Little is known about germination requirements of many of these shrub species, but seedlings may more commonly be found in recently burned areas than in undisturbed pocosin habitats (Christensen et al. 1981). 46 Many pocosin shrubs, in addition to being fire tolerant, also have evergreen sclerophyllous leaves (reinforced with lignin and having thickened cuticles). Just how this feature may serve as an adaptation for survival in these environ ments is not understood. Such sclerophylly is usually considered to be an adaptation to drought rather than to high moisture conditions (Christensen et al. 1981). An early theory regarding the occurrence of sclerophyllous shrubs in these wet habi tats proposed by Schimper in 1898 (cited by Christensen et al. 1981) is that anae robic conditions in the rooting zone prevent water uptake and produce an effect similar to that of drought. This theory, however, has been considered unlikely by more recent investigators (Schlesinger and Chabot 1977). Other workers (Monk 1966, 1971; Schlesinger and Chabot 1977) have specu lated that sclerophyllous leaves could be an adaptation to conserve nutrients in these nutrient deficient habitats, al though the specific mechanisms of such nutrient-conservation are neither under stood nor agreed upon. Schlesinger and Chabot (1977) have further suggested that certain evergreen pocosin species (e.g., fetterbush) may have a significantly higher efficiency of nutrient use (espec ially of nitrogen) than do their deciduous counterparts. Direct measurements of photosynthesis anr1 of nutrient-use effic iency in pocosin species necessary to com pare evergreenness and deciduousness have not yet been conducted (Christensen et al. 1981). Evergreen sclerophyllous leaves may be more resistant to herbivory than are deciduous leaves (Christensen et al. 1981). In addition, the leaves of many pocosin species contain large quantities of secondary chemicals that may also have a role in defense against ' herbivores. High levels of these aromatic compounds also increase the caloric contents of these tissues (Hough 1969) and their flam- mability (Christensen 1980). It should be noted that the presence of insectivorous plants, especially pitcher plants (Sarracenia flava and S. purpurea) and sundews fDrosera spp.), in open areas of these shrub bogs also suggests adaptations to low nutrient-lev els (Figure 19). The leaves of these plants are morphologically modified to at tract and trap insects. Enzymes secreted by the plants then digest the bodies of the insects. In this way, insects may serve as alternative nutrient sources to meet nitrogen and phosphorus requirements in these species (Plummer 1963; Christen sen 1976). Little is known about the productiv ity or standing crop of biomass in pocosin communities. Christensen et al. (1981) cited data (Wendel et al. 1962) indicating that in very nutrient-poor areas above- ground biomass, excluding tree trunks, may be 1200 to 1800 g/m2. Such values nay be characteristic of low or short pocosin (Figure 14). In more productive areas (high or tall pocosin), biomass may be 3300 to 4700 g/m2. Apparently, no reli able estimates of belowground biomass have been published. V v t Figure 19. The pitcher plant (Sarracenia pur purea) is adapted to nutrient-poor pocosTn soils. (Photograph by Tr'p Lamb. University of Georgia.) 47 Carolina Bays Because Carolina bays are the domi nant lentic habitats of a large portion of the southeastern Coastal Plain, they have a major ecological influence on plant and animal distribution patterns. In addi tion, because of their probable age, they may have influenced the evolution of some species. A number of wetland community types typical of undrained Coastal Plain sites are found within Carolina bays (Figures 20 and 21). These moist wetland habitats are readily distinguished in aerial photo graphs from surrounding upland pine and oak forests. The gradually sloping con tours that characterize Carolina bay depressions result in gradients of water depth or soil moisture, as well as sub strate characteristics, across the basins. In response to these gradients, plant com munities typically show a marked pattern of zonation from the periphery of the bays to their center. Figure 20. Aerial view of vegetational zone pattern around a Carolina bay. Schalles (1979) noted that topo graphic relief and hydrology are the prin cipal physical determinants of vegetation al composition, although edaphic (soil) conditions also play a role. The duration and magnitude of inundation create a range of conditions favoring different vegeta tion associations. Although many of the bays contain pocosins or similar evergreen shrub communities (Figure 2), other types of plant associations such as cypress-gum forests are also common. Characterization of Carolina bay vég étât IÖ1ÜCarolina bays have received even less ecological study than pocosins. In 1946, Buell (1946a and b) described the vegetation of Jerome Bog in Bladen and Cumberland Counties, North Carolina, as an open pocosin community on peaty soils with low evergreen shrubs overtopped by pond pine. In more recent mapping of the vege tation of Bladen County, Whitehead and Tan (1969) indicated that many of the bays of this region contained either mixed pine communities or shrub bogs. Where the water table was close to the surface, a bay forest developed, dominated by pond pine along with loblolly bay, sweet bay, red bay, and sweet gum over a shrub layer of titi, sweet pepperbush, and wax myrtle. The pocosin community, which occurred in peat beds, was dominated by the typical bay shrubs and small trees (loblolly bay, sweet bay, and red bay) as well as red maple, pond pine, sweet gum, cypress, Atlantic white cedar, and black gum over topping a shrub layer of titi, sweet pep perbush, holly, gallberry, Virginia wil low, fetterbush, zenobia, leucothoe, blue- berry, and greenbrier. Whitehead and Tan (1969) also provided basal area data for the tree species in these communities. The nature of pocosin vegetation has been extensively described in the previous sec tion of this community profile. There fore, the discussion at this point will be directed toward other plant communities found in Carolina bays and their relation ships to the pocosin type. Porcher (1966) surveyed the vege tation zonation patterns of selected Carolina bays in Berkeley County, South Carolina (Figure 21). Several of the bays were dominated by evergreen shrub bogs characterized by both tall and short shrub zones of pocosin species. In addition to 48 MIXED HARDWOOD x^o SWEET PEPPERBUSH SHRUB BOG | ""1 CYPRESS-GUM FOREST FZZm HARDWOODS WITH SHRUB iaaaa UNDERSTORY ( ]CYPRESS POND MUDV1LLE ROAD MUDVILLE ROAD BAY Figure 21. Vegetation types of a Carolina bay that are characteristic of many undisturbed sites (from Porcher 1966). 49 pocosins, several of these bays had a cypress-gum community with pond cypress and black gum and a low herbaceous zone containing species of yellow-eyed grass (Xyris spp.)» pipewort (Eriocaulon decan- gulare), clubmoss (Lycopodium al'opecie- roides). St. Peter's-wort (Hypericum stans), zigadenus (Zigadenus galberrimus), cinnamon fern (Osmunda cinnamonea),and others. The edges of these bays were com monly dominated by pond pine or loblolly pine along with a variety of shrubs or by a mixed nesophytic hardwood forest charac terized by red maple, mockernut hickory (Carya tomentpsa), flowering dogwood (Cornus floridaT, water oak (Quercus nigra), and sweet gum. In the other bays, Porcher (1966) found cypress and gum forests to dominate. A mixture of shrubs including fetterbush, leucothoe, sweet pepperbush, zenpbia, highbush blueberry, and Virginia willow (Itea virgim'ca) commonly grew around the bases of the cypress and gum or on slight ly higher areas. The three species of bay trees also were commonly present. A mixed hardwood forest typically occurred on the edge of these bays, and aquatic macrophy- tes dominated the open water areas. Patterns of vegetation zonation. Craig Pond, a bay approximately 1400 m (4,600 ft) long on the Savannah River Plant in Barnwell County, South Carolina, demonstrates the marked zonation pattern of vegetation characteristic of many of these wetlands (Kelley and Batson 1955). The outermost zone lies along the sandy rim of the bay and is dominated by trees such as loblolly and longleaf pine, black gum, blackjack oak (Quercus marilandica), turkey oak (£. laevis), and sweet gum. Several shrubs, such as sumac (Rhus copal- lina), gall berry, and sweet bay also occur here. Interior to this zone of woody spe cies are several bands of vegetation, each of which is dominated by grass species. The first is characterized by broomsedge, but also contains numerous herbs includ ing pitcher plants. Inside of this zone is a band in which three-awn grass (Aris^ tida affinis) is dominant, and in deeper areas surrounding the central pool of water, species of maidencane (Panicum spp.) are abundant. The pond in the mid- dle of the bay contains typical aquatic plants such as the water lilies, Nymphaea odorata and Nymphoides aquaticum. Kelley and Batson interpreted this zonation pat tern as a successional series that devel oped as the pond receded and new soil sur face was exposed for plant invasion. Those areas farthest from the pool that have been exposed longest have developed a woody flora. The more recent exposures show successively earlier successional stages. However, no temporal comparisons have been made on Craig Pond or other Carolina bays to document that Carolina bays follow a classical pattern of hydric succession. Based upon descriptions of Carolina bay vegetation by Penfound (1952), Porcher (1966), and Wharton (1978), a qualitative arrangement of these wetland communities was proposed by Schalles (1979) using the average water level and hydroperiod ampli tude as controlling environmental factors. Major types of communities prdinated along these environmental gradients included pine forests or savannas, herbaceous marshes, shrub bogs, deciduous forests dominated by black gum, evergreen bay for ests, pond cypress swamps, pond/grass prairies, and lakes. Many of these com munity types are partly maintained by burning (Wharton 1978). In the absence of fire, peat accumulates and the changing substrate conditions allow new plant spe cies to invade. During drought, however, the peat becomes vulnerable to fire, which can set back the process of ecological succession. Vegetative dominance in Carolina bays may be strongly related to patterns of disturbance as well as, to hydrologie regime. A large bay in Bullock County, Georgia, which had been heavily forested with cypress and subsequently logged, had a fringe of black gum surrounding zones of emergent grasses and sedges and of sub merged water milfoil (Myriophyllum spp.; Wharton 1978), which replaced the timbered trees as dominant species. A less dis turbed bay in Jenkins County, Georgia, exhibited at least five zones of vegeta tion (Wharton 1978): (1) a-- rim dominated by a scrubby forest of red cedar (Juni perus virginiana) and black cherry (Prunus serotina); (2) ~a second zone of loblolly pine, sweet gum, and greenbrier, (3) a more moist zone of wax myrtle and red maple; (4) a zone of water willow (Decodon 50 verticil lata). lizard's tail (Saururus cernuus), bulrush (Scirpus cyperinus), and giant plume grass~TEri'anthus gigantea), and (5) open water with scattered button- bush (Cephalanthus occidental is) and cypress trees. A third bay in Tel fair County, Georgia, which showed signs of being burned about 20 years earlier, con tained no trees but an almost pure stand of maidencane and several species of water lilies (Wharton 1978). Few studies of the primary productiv ity of these diverse wetlands have been conducted. Schalles (1979) described the vegetation of Thunder Bay on the Savannah River Plant in Barnwell County, South Carolina, as having an interior herbaceous community dominated by maidencane and cut- grass (Leersia spp.), and a deeper central area of water lilies and water shield (Brasem'a schreiben'). Root materials dominated the biotic structure of the ponded area with an average dry weight standing crop of 780 g/m2. Root/shoot ratios were high and averaged about 8, with a range between 4 and 13.5. Total net primary production of the macrophytes averaged about 260 g/m2/yr dry weight. 3.2 ANIMAL COMMUNITY COMPOSITION Pocosin Fauna Pocosin communities are invaluable to the welfare of certain animal species in some regions because they provide the only habitat available. Although few or no species of animals are known to be depen dent on pocosins per se, a basic problem may be that pocosin dependents have not been identified because only limited for mal studies have been conducted in these shrub bog habitats. The finding that cer tain subspecies (e.g., the Dismal Swamp southeastern shrew, Sorex longirostris fisheri ; Cooper et al. 1977) are endemics in particular pocosin areas is indicative that these specialized habitats may be critical for many species. Another problem in recognizing ende mic species may be confusion in taxonomic classification. For example, the Dismal Swamp shört-tailed shrew (Blarina telma- 1 estes) was described as a distinct spe cies by Merriam (1895) and recognized as such by Hamilton (1943). Later general accounts' (e.g., Blair et al. 1968; Burt and Grossenheider 1976) include the Dismal Swamp short-tailed shrew within the spe cies Blarina brevicauda. but the taxonomic status is still controversial. Whether or not true endemic species actually exist, the apparent lack or limi tation of such endemism may merely be a function of insufficient research. This seems to be the message of Wilbur (1981), who indicated that a thorough literature search in ecological journals revealed little on pocosin fauna. This dearth of such fundamental information as formal lists or basic life history studies indi cates a need for primary level studies of animals in these areas. Although no animal species has yet been recognized as a true endemic of poco sins, Wilbur (1981) stated that the pine barrens treefrog (Hyla andersoni ; Figure 22) might be considered to be a vertebrate "pocosin endemic." He permitted, however, the.widest possible definition of a poco sin. In fact, the potential occurrence of pine barrens treefrogs in non-pocosin hab itats (Martof et al. 1980; Tardell et al. 1981) and in geographic regions outside pocosin areas (Conant 1975) make this spe cies only marginally qualified as an ende mic. Nevertheless, pine barrens treefrogs can firmly be declared as characteristic of and indigenous to pocosin shrub bogs as well as to similar habitats in other areas. Another vertebrate species character istically found in pocosins where such habitat is within its geographic range is the spotted turtle (Clemmys guttata, Wil bur 1981). Both spotted turtles and pine barrens treefrogs thrive in the temporary, shallow ponds (Ernst and Barbour 1972; Martof et al. 1980) found on many pocosin sites. Presumably, any reptile or amphi bian species whose geographic range encom passes pocosins, at least as transients, would not be excluded from species lists, unless some feature of its natural history (such as dependence on flowing water or sandy, arid conditions) precluded its presence. The same would presumably be true for snail mammals. Again, the pau city of research on this facet of pocosin ecology severely limits our understanding of the true situation. 51 Many bird species in the region feed or nest in tall evergreen shrub bogs as readily as in other similar habitats. Anschein (1981) listed bobwhite quail (Colinus virginianus), mourning dove (Zenaida macroura), and American woodcock (Scolopax [formerly Philohela] minor) as utilizing pocosins to some extent. Bob- white quail and dove are able to subsist under agricultural regimes whereas wood cock do not fare as wel 1. Therefore wood cocks probably benefit most from pocosins because of the destruction and elimination of other suitable habitats. Robinson and Barkalow (1979) reported that the develop ment of an edge habitat and herbaceous vegetation in pocosins converted to pine plantations enhanced bobwhite quail popu lations at least initially. Waterfowl, of course, utilize lakes associated with pocosins during migratory activities, but, as far as is known, to no greater extent Figure 22. The pine barrens treefrog (Hyla andersoni). an amphibian species indigenous to pocosin habitats. (Photograph by Trip Lamb, University of Georgia.) than other lakes of a region. Lake Matta- musket and Pungo Lake within the extensive pocosin area of the Albemarle-Pamlico peninsula in North Carolina are estab lished waterfowl refuge areas (Ash et al., in press). Potter (1982) reported 83 species of wintering birds in pocosins, including both shrub areas and areas with trees in Dare County, North Carolina. She concluded that the species were those ex pected to be found during winter in other parts of North Carolina's lower Coastal Plain. Permanent aquatic sites associated with pocosins have species of fishes typical to the region, although no species has been classified as a pocosin endemic. Monschein (1981) listed nine species of game fishes commonly found in such aquatic habitats, including two pickerel (Esox spp.), yellow perch (Perca flavescens), and several sunfishesC^entrarchidae). Three small game mammals (marsh rabbit, Sylvilagus palustris; cottontail, S^. floridanus; and gray squirrel, Sciurus carol inensis) are found in pocosins (Mon schein 1981_), but only the marsh rabbit can be considered characteristic. Cotton tails and gray squirrels are usually asso ciated with habitats marginal to pocosins rather than being found throughout the shrub bog communities. Among the mammals, the black bear (Ursus americanus) is considered to be characteristic of pocosins in parts of North Carolina (Figure 23). This rela tionship is partially one of default in that few of the other remaining natural habitats in the region are extensive enough to support bears (Monschein 1981). Monschein estimated that 750 to 1000 black bears are left in the region of eastern North Carolina. Most of these are found in pocosins, presumably indicating the importance of the shrub bog habitat to this species regardless of the condition of surrounding habitats. The Great Dismal Swamp National Wildlife Refuge and asso ciated areas are the last refuge of the black bear in the Virginia Coastal Plain (Rose 1981). The largest remaining popu lation of the bobcat (Lynx rufus) in that region is probably also located there (Rose 1981). 52 White-tailed deer (Odocoileus virgin ianus) inhabit pocosins, although their population densities are far below those in certain other natural habitats of the region. For example, 6 deer/mi2 are found in pocosins compared with 18/mi2 along pocosin borders and up to 40/mi2 in bot tomland hardwood forests in the coastal region (Monschein 1981). This may be a function of limited amounts of available deer browse plants in pocosins. Most of the regional furbearing mammals are also found in pocosins (Monschein 1981). Bob cat, gray fox (Urocyon cinereoargneteus). raccoon (Procyon lotoTITand opossum (Pidel phi s marsupial is) are found through out the shrub bog community, whereas river otter (Lutra canadensis), mink (Mustela vison), and muskrat (Ondatra zibethicusT are restricted to suitable aquatic areas within pocosins. The most likely endemic fauna to pocosins are to be found among inverte brate species that have parasitic or mutualistic relationships with indigen ous plant species. Two lepidopteran Figure 23. The black bear (Ursus americanus). a major game species dependent on pocosin habitat in the lower Coastal Plain of North Carolina. (Photograph by T. R. Smith, University of Tennessee.) species -- a swallowtail (Papiljo pala- medcs) and Hessel's hairstreak (Mitoura hesseli) ~ are dependent as larvae on particular plant species (red bay and Atlantic white cedar, respectively) char acteristically associated with pocosins (Wilbur 1981), although both tree species are also found elsewhere. Intensive studies of particular species of plants that are indigenous to and practically restricted to pocosin-type habitats might reveal dependencies that restrict certain animal species to pocosin areas. Further studies are needed to address this issue. A final consideration is that suffi cient research might reveal that pocosins are key habitats for certain assemblages of animals. That . is, whereas any given species might be expected to be found in other habitat types, the community makeup of animal species may be unique to poco sins. Such possibilities can only be investigated by thorough faunal surveys of these ecosystems throughout their range. Carolina Bay Fauna Carolina bays are vital focal points in the life histories of a variety of non-aquatic vertebrate and invertebrate species. Although larger Carolina bays have resident fish populations of several species (Frey 1951a; Bailey and Frey 1958), it is likely that the majority do not have permanent fish inhabitants be cause of their often transitory aquatic status. Of more than 150 Carolina bays on the Savannah River Plant in South Carolina (Shields et al. 1980), fewer than 10% are known to have permanent populations of fish, although overwash from neighboring swamps or streams may re-establish the ichthyofauna of previously dry basins. The situation is different in some of the larger bay lakes (Frey 1948a) that are never threatened by drought. The most thorough fish studies have been conducted on several Carolina bays in North Carolina, revealing the presence of 8 to 17 species in each of five bays and 25 in a sixth (Lake Waccamaw) (Frey 1951a). Four of the species from Lake Waccamaw, which covers more than 3200 ha (approximately 8000 acres), were origi nally reported as endemic to this particu lar Carolina ,bay (Fowler 1942; Hubbs and 53 Raney 1946). The species are the Waccamaw minnow (Notropis waccamanus), thé Waccamaw k i 1 1 1 fi sfi (Fundulus waccamensis) , thé Waccamaw glassminnow [Mem'dia extensa), and thé Waccamaw darter (Etheostoma perlongtim). Of these species, the endemic status has remained intact and unquestioned for the qlassminnow and the darter (Lee et al. 1980 J. The Waccamaw killifish may also be endemic to Lake Waccamaw if a recent sample of the species reported from Phelps Lake (which is located within a pocosin area in North Carolina) is an introduction and it does not occur there naturally. The Waccamaw minnow, originally reported by Fowler (1942) as endenic to Lake Wacca maw, was later considered to be a varia tion of N^. petersoni (Hubbs and Raney 1946; Frey 1951a), a wide-ranging minnow species. Nonetheless, at least two, pos sibly three, fish species are natural endemics of this particular Carolina bay. Perhaps because of the fluctuating water levels and the potential for complete dry ing, ichthyologists have not focused on these habitats as study sites. Therefore, although fish populations may occur in many bays for temporary periods (sometimes up to several years), few intensive stud ies have been made. Lake Waccamaw is further recognized as a unique habitat in having three endemic species of mollusks. These are the Waccamaw spike (Elliptio waccamawen- sis) , the Waccamaw mucket (Lamps il is radi- ata). and the Waccamaw Tance rËTlip sp., not yet officially described), all of which are known only from Lake Waccamaw (Fuller 1977). As with the aforementioned fish species, however, the mollusks are endemic to the particular lake, not to Carolina bays as a habitat. Although fishes are not a dominant feature in most hays, secondary productiv ity may still be high. The use of bays by vertebrates is sometimes astonishing (Table 9)^ as revealed by the high number of semi-aquatic animals migrating to or from the water (Figure 24). Rainbow Bay (on the Savannah River Plant in South Carolina), which has an aquatic perimeter of less than 450 m (1476 ft), had approxi mately 10,000 southern leopard frogs (Ran a utricularia) moving in or out in 1 year. This is an average of one frog for every 2 cm of lake margin. A similar calcula tion for Ellenton Bay, which is much larger, indicates that more than one adult nole salamander (Ambystoma talpoideum) per 20 cm (8 inches) of perimeter enters the lake for breeding purposes each winter (Patterson 1978) and as many as 11,000 recently metamorphosed individuals may exit during 1 week. These 11,000 sala manders are equivalent to 1/11 cm of aquatic perimeter and a total biomass of 70 kg that emigrated from a single Caro- 1ina bay in 1 year. The abundance of amphibians even in Carolina bays altered by agricultural, forest management, or construction activi ties (e.g., Sun Bay, Table 9; Lost Lake, Bennett et al. 1979) may be higher than expected. In/1979, more than 500 ornate chorus frogs (Pseudacris ornata). 5,000 southern leopard frogs, and 500 mole sala manders entered or left Sun Bay, an area on the Savannah River Plant of less than 1 ha (2.5 acres) drained by construction activity in the previous year. Similarly, Lost Lake on the Savannah River Plant has undergone human alterations in the form of agricultural impacts prior to the 1950s and the later release of industrial pro ducts into the lake (Bennett et al. 1979). Half of this bay is now bordered by man aged pine plantations. Nonetheless, extrapolation of captures by intermittent fencing and pitfall traps to the entire portion of the lake surrounded by the pine plantations yields an estimate of more than 5,000 southern toads (Bufo terres tris), 2,000 mole salamanders and 1,000 spadefoot toads (Seaphiopus holbrooki) that left or entered Lost Lake during a single summer. These numbers provide convincing evi dence that the Carolina bays are important natural habitats for many species, some of which may have a high resiliency to envi ronmental disturbance. This does not imply that extensive'municipal or agricul tural development of such sites would not result in the eventual demise of the amphibian populations. 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COft. vt w ro O 56 Although amphibians are the prevalent terrestrial vertebrate species utilizing Carolina bays (Patterson 1978; Bennett et al. 1979; Semlitsch 1980) and the major contributors to secondary productivity in such communities, other vertebrates often depend on Carolina bays. Indigenous rep tiles include the American alligator (Alligator mississippiensis) (Figure 25) and several species of aquatic turtles (Table 9, Figure 26; Gibbons 1970) and snakes (Table 9; Gibbons et al. 1977). Though quantitative data are unavailable, large animals like deer, raccoons, and skunks may use bays for water or feeding sites. In sandhill regions of the Caro- linas, various aquatic birds such as egrets, coots, and migratory waterfowl use bays during part of the year. In areas with standing water and mature trees with cavities for nesting sites, as around the perimeter of some Carolina bays, wood ducks (Aix sponsa) may also be found. Again, quantitative estimates are lacking, but personal observations and those of associates indicate the presence of these animals in most water-containing Carolina bays that have been studied on the Savan nah River Plant in South Carolina. Quantitative data are available for many small mammals using the periphery of Carolina bays (Table 9). Though shrews (Blarina brevicauda and Sorex longirostris)and small rodents (Siqmodon nispidus, Peromyscus gossypinus, and MicrotuT pinetorum) nay be iïïundant, only certain species, e.g., the rice rat *; >« \ Figure 24. A drift fence with pitfall traps at Ellenton Bay, SO, the most thoroughly studied Carolina bay from a fauna! standpoint. See text for description of technique. 57 (Oryzonys palustris), are actually con fined to marshy areas. Many small mammals captured by drift fences and pitfall traps (Figure 24; Gibbons and Semlitsch 1982) around Carolina bays are equally abundant in strictly terrestrial habitats in the region (Briese and Smith 1974; Brown 1980). While numbers of individuals of cer tain snail terrestrial or semi-aquatic vertebrate species are extremely high, no species are known to be endemic to any particular Carolina bay or to the habitat type. This is due in part to the highly transient nature of most species that rely on Carolina hay depressions as aquatic sites. Total animal biomass often cannot be ascertained because obtaining field weights is difficult. Approximations for some species are possible on the basis of weight-length relationships. The overland movement of juvenile and adult mole sala- nanders at Ellenton Bay in 1 year (1981) was estimated at more than 60 kg (132 Ib). Based on presumably an exceptionally high survivorship in 1979, about 30 kg (66 Ib) of southern leopard frogs, predominantly juveniles, left Rainbow Bay. The total biomass of all amphibians utilizing a Carolina bay habitat is more difficult to estimate. However, based on the length-weight relationships and abun dances of five dominant species typically found in Carolina bays on the Savannah River Plant in South Carolina [redspotted newts (Motophthalmus viridescens), south ern toads, mole salamanders, southern leopard frogs, and spadefoot toads], it was estimated that animals constituting a biomass of several hundred kg moved between land and water in a typical year. The average distance traveled away from the aquatic habitat by one of these species (the mole salamander) is about 200m (660 ft) (Semlitsch 1981b), which would represent an estimated density of 1.7 kg/ha (9.2 lb/acre) of adults and juveniles around Rainbow Bay in 1981. Such estimates for the Southeastern United States are not surprising when considering the estimates^!- 1.8 kg/ha or 9.8 lb/acre) of Burton and Likens (1975) for terres trial salamanders at the Hubbard Brook Experimental Station in New Hampshire. The estimates for the Savannah River Plant are extremely conservative and nay repre sent absolute minimal levels for most Carolina bays. Figure 25. A "gator hole," indicating how a single species, the American alligator (Alligator miss- isslppjensis). can influence the ecology of a Carolina bay during a drought. This subhabitat 'n the depression of Ellenton Bay on the Savannah River Plant in South Carolina Is approximately 1 m (3 ft) deeper than the surrounding area and Is 2 m (6 ft) deep during most years, when the remainder of the bay. (about 10 ha or 25 acres) is 0.5 to 1 m (1.5 to 3 ft), deep. Larva sala manders, tadpoles and a single species of fish (Gambusla affinis) are the only, vertebrates remaining in the "gator hole. 58 3.3 ENDANGERED AND THREATENED SPEC ES Although pocosins or Carolina bays cannot be classed as essential to the welfare of any species throughout its range, these ecosystems can be vital in certain regional situations, sometimes because they are the only available refuge areas for wildlife species. Mo endangered species of plant or animal is endemic to pocosins or Carolina bays. However, many species recognized as threatened or endan gered at State or Federal levels (e.g., the American alligator and pine barrens treefrog) use these habitats, even though the use is not exclusive except in re stricted areas. Likewise, many plant spe cies indigenous to pocosins [e.g., white wicky (Kalmia cuneata) and rough-leaf loosestrffeflysimachia asperulaefolia)] may be uncommon and in danger (Richardson 1982) although legal endangered status is Water Illy (Nelumbo jutea) Mud turtle (Klnosternon subrubrum) Figure 26. Species adapted to fluctuat'ng water levels characteristic of Carolina bays. not recognized. With the present limited level of biological information available about pocosins and Carolina bays, neither ecosystem can be considered the sole, suit able habitat available for any plant or animal, but more thorough study may reveal unexpected dependencies of certain species to these areas. 3.4 POCOSINS AND CAROLINA BAYS AS REFUGE AREAS Few data have been collected on the use of shrub bog communities as re fuge areas by animals. The importance of pocosins as refuge habitats in the man- influenced Coastal Plain region was noted in a general manner by Wilbur (1981) and specifically for black bears by Monschein (1981). The Dismal Swamp is a last refuge for bears in coastal Virginia (Rose 1981). Pocosins may be used as last resort refuges because they represent the only extensive, unexploited habitat in certain areas (Wilbur 1981). Thus, they serve as sanctuaries because of the limited access by man and not because they are particu larly desirable habitats from the stand point of community diversity or productiv ity. Carolina bays are refuges in a dif ferent manner although they are character istically smaller, disconnected habitats that cannot serve as effective retreats for larger animals such as black bears. Nevertheless, for smaller-sized species, particular bays may provide critical aquatic habitat during droughts. Larger Carolina bays can become refuge areas for some animals (e.g., turtles) that normally reside in smaller bays in the vicinity. During periods of drought, the smaller bays may dry up, but the larger ones (nay continue to retain water to which mobile species can migrate. In urban or inten sively farmed areas, many species of amphibians, reptiles, and small mammals unquestionably have clumped distribution patterns, with the areas of highest densi ties being associated with Carolina bays. This phenomenon is comparable to that of pocosins in that other communities (e.g., bottomland hardwood) might be more desir able, but their elimination leaves the Carolina bay as the most suitable remain ing habitat. 59 Although qualitative observations have revealed the importance of these wetlands as refuges under various circum stances, no quantitative assessment of the extent to which pocosins or Carolina bays serve as refuge areas for animals has been made. Such studies would be particularly valuable in establishing how important these particular habitats are to wildlife confronted with urban, agricultural, or other land-use practices that are rapidly eliminating most natural habitats includ ing these potential refuge areas. 3.5 TROPHIC RELATIONSHIPS IN POCOSIN AND CAROLINA BAY ECOSYSTEMS No quantitative studies have been carried out on food web dynamics or the interactions among trophic levels of shrub bog communities. Certain conclusions, however, can be drawn from general ecolog ical information about the dominant plants and animals inhabiting the communities and the nutrient conditions that are known to exist. One feature of evergreen shrub vegetation is sclerophylly, a characteris tic resulting in highly cutinized, pro tected leaves that are not suitable for most grazing herbivores, either insect or vertebrate. Although data have not been collected on this subject, our prediction is that the shrub bog terrestrial plants are highly conservative in regard to nu trient loss (through grazing or deciduous- ness). Therefore, the energy flow from primary producer to primary consumer is probably extremely low. Consequently, secondary and tertiary consumers should be accordingly reduced. A comparative dif ference between evergreen shrub bog com munities and surrounding, high productiv ity habitats should be that the terres trial animals in the food chain would have a much lower biomass in relationship to the total standing crop biomass. Second ary productivity and turnover in an ever green shrub bog community would be apprec iably lower per standing crop of terres trial vegetation than would be true for most other Atlantic Coastal Plain communi ties. This idea is testable by standard field techniques and studies that would provide a,better understanding of trophic dynamics in these systems. The insectivorous plants of these acidic peat bogs present a fascinating module for studies of trophic dynamics and evolution. Insectivory is apparently an adaptation to the low availability of nu trients in a peat substrate and is a mech anism for obtaining a nutrient supply to augment that provided through the soil. Two questions arise from a nutrient dyna mics standpoint: (1) What proportion of a plant's nutrients are provided by insects? (2) What proportion of the consumed insects have obtained their own resources from outside of the pocosin or Carolina bay community? These questions deserve attention by ecologists interested in the biology of insectivorous plants and their value in the shrub bog community. The most poorly studied aspect of trophic dynamics in these systems is the aquatic community. Aquatic plants and animals are found in pocosins and Carolina bays, and in the latter there is evidence that the semi-aquatic, temporary species sometimes occur in remarkable numbers. A primary question, unanswered by present information, is what proportion of the animal biomass inhabiting the aquatic por tion of a Carolina bay or pocosin repre sents energy and resources obtained within the shrub bog ecosystem? Secondly, what is the turnover rate of aquatic plant bio mass relative to its standing crop and also relative to the turnover rate of the terrestrial plant portion of the commun ity? Information on these and similar aspects of these communities would enhance our understanding of the biology of these complex ecosystems and could lead toward greater predictability of how particular environmental perturbations might affect these ecosystems. Trophic dynamics is a critical, essentially unstudied, aspect of the biology of shrub bog communities. Food webs and trophic interaction are complex biological phenomena that are seldom quantitatively known for an entire com munity. Therefore, it is not surprising that the trophic dynamics/of shrub com munities are poorly known. This area deserves special attention at this time to develop our understanding of the trophic relationships within these communities and between them and adjoining ecosystems. Shrub bogs are potentially linked with 60 human food chains through various water fowl and wildlife species. This could be substances that are toxic or harmful. In addition, movement of contaminants to particularly important in areas where adjacent ecosystems, such as estuaries, direct chemical contamination of the envi- could result in uptake of toxic substances ronment through industry, pesticides, or by other species, such as fish or shell- herbicides occurs. Such contamination fish, consumed by humans, could result in transfer to humans of 61 CHAPTER 4 INFLUENCE OF HUMAN ACTIVITIES ON POCOSNS AND CAROLINA BAYS 4.1 HISTORICAL PERSPECTIVES Pocosins and Carolina bays have been under the influence of humans for several hundred years, and it is difficult in many Instances to establish what a particular habitat would be like, had there been no human intervention. The earliest effects came as a result of burning by Indians (Wells and Whitford 1976), although it is obvious that natural fires would have created similar situations. The usual events associated with fire in these habi tats came as a consequence of heavy peat build-up, a dry period, and then a sweep ing fire that burned not only vegetation but the peat soil itself. Thus, many pocosin ecosystems, including the Carolina bays, may have much shallower organic deposits today than at some point in the past. This consequence of fire must be taken into account in evaluating previous and future studies in regard to the level of the peat deposit and what interpreta tions should be given to it. The next major impact on all such habitats came in the early development period of the Eastern United States as a result of widespread timbering operations. Large trees in the pocosin expanses, particularly in North Carolina, were removed during this time and have not been replaced. Therefore, it is not known how much of what is now shrub bog was once sparsely or densely populated by larger trees. The same would be true for some Carolina bays in which tree removal around the margins could have taken place more than 200 years ago. Timber removal has undoubtedly had a major impact on the character of these communities, particu larly the pocosins, and its total influ ence may never be thoroughly resolved. Because of its accessibility, one of the first areas that included pocosin vegetation to be drained and logged was associated with the Great Dismal Swamp (Lilly 1981b). The Virginia Assembly in 1764 chartered the Dismal Swamp Land Com pany, of which George Washington was a member, to drain 16,188 ha (40,000 acres) of rich timber!and in the swamp. To facilitate logging, a canal (the Washing ton Ditch) was dug across swamp land to Lake Drummond (Lilly 1981b). Plans by the company to farm the swamp after timbering failed. Although several other shallow swamp lands were drained for agriculture in the late 1700's, a major boom in development came after the Revolutionary War, spurred by interest in cultivating rice and in logging cypress and by the attitude that draining swamp lands would reduce malaria (Lilly 1981b). Major draining, logging, and clearing took place in the Dismal Swamp, at Lake Phelps, and elsewhere on the Albemarle-Pamlico peninsula, including Lake Mattamuskeet, Alligator Lake, and Pungo Lake, and in the Open Ground Swamp in Carteret County, North Carolina. Num erous land ownership companies were estab lished for development purposes. However, by the late 1800's the failure of many of these organic soils to sustain high agri cultural yields was becoming apparent, although plant nutrition was not well understood. Most of these efforts to develop pocosins for agriculture subse quently failed without the input of com mercial fertilizers, and by 1880 emphasis had shifted from aariculture to forestry (Lilly 1981b). *The logging history of the Green Swamp in Brunswick County, North Carolina, is typical of that of many pocosin areas. According to Kologiski (1977), logging began shortly after 1861 when the Green Swamp Company purchased a large portion of the property and selectively cut large 62 cypress trees to be processed into shin gles. The timber resources of the Green Swamp were described as tremendous in an 1870 survey in which cypress, gum, white cedar, and yellow pine were listed as dom inant species. Between 1870 and the early 1900's, much of the property changed own ership several times. In 1906 it was pur chased by the Waccamaw Lumber Company, which cut most of the forested areas of the swamp during the next 34 years. Large areas of brush and tree remnants were left from the lumbering activities and these waste areas were commonly burned. Growth of fire-tolerant species such as titi, zenobia, and pond pine was therefore fav ored in the successional recovery of the disturbed pocosin and swamp areas. Drainage of the Green Swamp had begun by 1937 when Riegel Paper Corporation purchased much of the land. Secondary roads and additional drainage ditches were constructed, and an active land management program was developed that included wild fire control, controlled burning, road and canal building, and reforestation (Kolo giski 1977). By clearing and draining, areas of the Green Swamp dominated by pond pine are presently being converted to pine plantations. In 1977, approximately 4800 ha (12,000 acres) per year were being planted with loblolly pine. To complete the history of the Green Swamp, it should be noted that in 1974 the Secretary of the Interior designated it as a Natural Landmark as prescribed by the National Park Service. In 1977, 5540 ha (13,850 acres) were deeded to the Nature Conservancy by the Federal Paper Board Company, Inc., which purchased land from Riegel Paper Corporation in 1972 and still retains ownership of part of the area. Other portions are still being managed as pine plantations. 4.2 CURRENT LAND MANAGEMENT PRAC TICES AND PERTURBATIONS Forestry During the last half-century, in creasing acreages of pocosins and coastal swamp lands have been managed for wood and wood products. Based on a survey of coastal tax office maps, industrial use maps and State maps, Richardson et al. (1981) estimated 44% of North Carolina pocosins to have been under ownership by major timber companies in 1980 (Figure 27). The increased use of these wetlands may be attributed to rising costs associ ated with upland pine management, an increasing demand for wood products, and a decline in the commercial forest land base because of urbanization and industrial land use (Jones 1981). Because lumbered forest land of the Coastal Plain was rela tively cheap, paper companies purchased large tracts from lumber companies and converted them to pine plantations (Lilly 1981b). This more intensive form of land management required ditching and canal construction. By the 1960's most pocosins were crisscrossed with networks of drain age ditches (Ash et al., in press; Figure 28) and only areas of deep organic soils unsuitable for loblolly pines were left unmodified. MAJOR TIMBER COMPANIES 44% LARGE CORPORATE AGRICULTURE 21% Figure 27. General pattern of ownership of pocoain habitats of North Carolina. (Redrawn from Richardson et al. 1981, in Pocos'n Wet lands: An Integrated Analysts of Coastal Plan Freshwater Bogs In North Carolina, ed. by C. J. Richardson. Copyright 1981 by Hutchlnson Ross Publ. Co., Stroudsburg. PA. Reprinted by permission of the publisher.) 63 "!,'••< ' i .'il ï , I > lî ''• V / ' i ' *l Newly constructed ditch (photograph courtesy of U. S. Fish and Wildlife Service). 11 Field ditch emptying into collector , '- *• ditch (photograph by Emilie S. Kane, East Carolina University). Electric pump station in eastern Hyde County. NC (photograph by Charles B. McDonald, East Carolina University).- Figure 28. Pocosin drainage for agricultural or forestry management. 64 Agriculture A major determinant of present-day habitat character that occurred during and subsequent to timber removal has been the agricultural development of many parts of the Coastal Plain. The low nutrient soils characteristic of pocosins and Carolina bays, as well as much of the region as a whole, resulted in marginally successful croplands that required extensive clear ing, burning, and draining. These activi ties greatly altered many of the shrub bog ecosystems. Farming required the removal of much of the shrub vegetation (along with the trees) in many areas. This resulted in a permanent change that is reflected in the plant communities present today. Agricultural activity has been centered in the Albemarle-Pamlico penin sula where three corporate farms have acquired over 160,000 ha (400,000 acres; Carter 1975 in Ash et al., in press). These farming activities converted poco sins and cut-over pine plantations to row crops. Since such fanning involves re peated use of heavy machinery, drainage had to be far better than required for pine plantations. Large-scale drainage with the con struction of major ditches and canals that traverse much of the pocosin ecosystem is therefore a required feature of such wet land agriculture in the Carolinas (Figure 28). Drainage ditches are also charac teristic of a large number of Carolina bays (Figures 29 and 30). In addition, surface vegetation and buried wood must be removed from the pocosin substrates by bulldozing and burning, and the land is commonly graded to an even slope of 0.5% prior to planting (Heath 1975). Thus the actual topography of such habitats may be changed in some instances. The ditches have resulted in surface water alterations by serving as collection points for surfi- cial water and by altering the drainage pattern of standing water of the localized watershed. In areas close to sea level, dikes and pumps may be installed to insure drainage, especially during periods of high rainfall. Agricultural development of the organic pocosin soils requires the addi tion of nitrogen, phosphorus, potassium, and copper, along with adjustment of the pH with lime (Ash et al., in press). Sub sequently, runoff waters from these devel oped lands may be altered. Kirby-Smith and Barber (1979) reported that turbidity increased 10 to 20 times, pH increased toward a neutral level, and nutrient con centrations in the ditches were 5 to 10 times higher in run-off from a pocosin converted to a pasture than from a natural pocosin stream. Little is known about the potential movement of pesticides from developed pocosin land in run-off water to adjacent aquatic habitats. However, Ash et al. (in press) pointed out that most nonionic pesticides are strongly adsorbed in soils of high organic content and may V \ i A.' * ' -* . 'I . Figure 29. Two views of major drought conditions in a ditched Carolina bay (Dry Bay, Savannah River Plant. SO in November 1981. Water level is nor mally more than 1 m h'gher. 65 be removed chiefly by erosion rather than by leaching in solution from the sub strate. Additional studies of the fates of individual pesticides in these highly organic substrates are required before general statements of their potential impact on receiving waters can be made. Drainage Systems Artificial drainage ditches in major pocosin areas lower water tables in the vicinity of the canals, increase runoff rates following precipitation, result in water quality alterations in runoff Ellenton, Barnwell County, SC Figure 30. Aerial view of Carolina bay habitats In an agricultural region In 1951 before develop ment of the Savannah River Plant. The large bay is Ellenton Bay; the smaller bay was drained by a ditch to provide additional use- able land for corn and cotton crops. Arrows Indicate location of drainage ditches leading through three Carolina bays into a natural drainage system. waters, and concentrate runoff into estu aries, both temporally and spatially (Kuenzler et al. 1977; Kirby-Smith and Barber 1979; Daniel 1981; Ash et al., in press). The high retention of water in porous, organic peat soil typically re sults in slow but consistent lateral move ment of groundwater in a natural pocosin. Therefore, the lowering of the water table that results from the movement of ground- water into drainage canals occurs primar ily within a few meters of the canal it self. Surface runoff into drainage canals is greatly affected by development of the surrounding land such that peak runoff rates are earlier and higher than is true of undeveloped lands. In addition, agri cultural development slightly increases inorganic nitrogen and sediment load in drainage waters and has statistically sig nificant but slight effects on various water quality features, such as dissolved oxygen, biochemical oxygen demand, and pH (Skaggs et al. 1980). In a natural pocosin, high precipita tion periods result in the accumulation of surface water on the flat surface, a grad ual absorbtion into the subsurface layer, and a slow lateral, but slightly downhill, movement to lower elevations. This lat eral movement is dependent upon the level of the water table and depth of the peat layer, degree of saturation, and state of decomposition of the peat. Lateral con ductivity of water in undecomposed peat is as high as 37 m (120 ft)/ day (Boelter and Verry 1977, cited by Daniel 1981) and as low as 0.030 m (0.097 ft)/day in well- decomposed peat (Lohman 1972, cited by Daniel 1981). Even at the highest rates of movement, sheet flow under natural con ditions is a moderately slow process that integrates peak precipitation periods so that final entry into an estuary is wide spread and temporally consistent, with rate changes being gradual. Ditching re sults in an immediate runoff response fol lowed by point entries into the estuary rather than a broad, peripheral input into the system. Although runoff is increased during peak flows, runoff, amounts during average flow periods are reduced so that the annual runoff in ditch-drained areas is not appreciably different from natural conditions (Daniel 1981). Many water quality characteristics of runoff into drainage ditches are different 66 from natural stream waters in pocosin habitats (Tables 3a and 3b; Kuenzler et al. 1977; Kirby-Smith and Barber 1979; Richardson et al. 1981, adapted from Barber et al. 1979). In a comparison of three natural streams and four man-made channels flowing through various habitats in Pitt County, North Carolina, Kuenzler et al. (1977) found that channelized streams, compared to natural areas, were higher in conductivity, turbidity, pH, phosphorus concentration, and nitrates. Although the studies were based on the channelization of tertiary streams drain ing upland areas with loamy and sandy soil, some of the interstream areas were low-lying "with scattered, large pocosins which form the headwaters of many of the streams" (Kuenzler et al. 1977). There fore, these findings can be applied to artificial ditches draining pocosin eco systems. In a comparison of a natural stream with ditches flowing through a pocosin that had been converted to agri cultural use in Carteret County, North Carolina, Kirby-Smith and Barber (1979; Table 3a) found runoff water in the ditches to be significantly higher in turbidity, pH, phosphates, and nitrates. Ammonia levels were also higher in the channels. Kuenzler et al. (1977) consid ered water quality differences between channelized and natural streams to be functions of (1) channels being straight and clear so that stream velocity (and turbidity) is increased; (2) channels cutting deeper into the substrate so that inorganic soils are exposed and contribute to increased solution of sodium, calcium, and phosphorus (thus increasing conductiv ity and pH); and (3) continual flow year- round compared with intermittent flow in natural streams. In addition, channelized streams are more likely to be located in heavily managed areas where soil amend ments or other surface additions are prev alent, thus affecting the quality of sur face waters as they enter the stream. In summary, draining ultimately af fects the input into estuaries by concen trating peak input periods into narrow time frames and localized points (Copeland and Hodson 1982). Thus, the natural sheet flow that distributes input waters in an equable manner under natural conditions is severely altered. In addition, the water quality is markedly different in several critical features. Thorough studies have not been conducted on how these changes affect estuarine flora and fauna that have evolved under the natural sheet flow con ditions. It is not known which water qual ity characteristics of pocosin runoff will prove to be most influential in the estu aries. Presumably the abnormal decreases in salinity, the raising of pH levels, the increase in siltation, and the increase in key nutrients could all have obvious as well as subtle effects on the estuarine ecosystems, although as Richardson et al. (1981) pointed out, the levels attained in the ditches may be reduced by the time of entry into the estuary. Localized industrial activities (be sides pocosin clearage and mining) such as the Texasgulf phosphate plant at Aurora, North Carolina, may also affect the estu aries bordering the North Carolina poco sins. Effects of pocosin clearage may be indistinguishable from these activities. For example, phosphate levels in the Pam- lico Estuary near the Texasgulf plant are already higher than normal for the area (Hobbie 1970, cited by Ash et al., in press). Future research will be necessary to document the important modifications in the plant and animal communities of the estuaries adjacent to pocosin habitats. The economic benefit of additional re search efforts is evidenced by the report of Street and McClees (1981) that the coastal fishing industry in North Caro lina is more than $300 million annually and could be jeopardized by abnormal inputs of freshwater pocosin .runoff. No quantitative assessment has been made on the extent or the hydrological impact of ditching on Carolina bays. It is apparent, however, from personal obser vations that the practice was extensive in heavily farmed areas of South Carolina (Figure 30) and that the draining effect was probably major. Carolina bays with large ditches generally dry up and can begin to support terrestrial vegetation while standing water remains in the ditch. How the water table itself responds and how far the influence of the ditch extends laterally are unknown. 67 Peat Mining Besides alterations resulting from draining, major environmental impacts have followed in the form of utilization of the substrate itself. A major commercial ex ploitation of the substrate of shrub bogs in the southeastern Coastal Plain could result from peat mining (Figure 31), an activity that may increase considerably in the future. Peat mining is most likely to be carried out in North Carolina where thousands of acres of pocosin are now owned by agricultural companies, some of which are involved in limited peat mining at this time. The peat substrates of the pocosins and Carolina bays have formed through decomposition of organic matter for sev eral thousand years in a water-saturated, anaerobic situation. Campbell (1981) described such peat as "young coal" and reported that the peat from First Colony Farms on the Albemarle-Pamlico peninsula of North Carolina has a British thermal unit (Btu) value of 10,189 per pound dry weight and a low sulfur content. It therefore compares favorably with coal (11,500-13,000 Btu/lb) in energy output (Campbell 1981). North Carolina peats generally have a lower layer about 1.2 m (4 ft) thick of brown, decomposed fibrous peat derived from Atlantic white cedar and herbaceous marsh plants (Ingram and Otte 1981a) and an upper layer of similar thickness of black, highly decomposed humic peat derived chiefly from cypress, tupelo, and pocosin vegetation with some white cedar (Otte 1981). Because of their large size, the peat deposits in the broad interstream pocosins are being most actively developed for min ing. The Albemarle-Pamlico peninsula has 932 km2 (360 mi2) of peatland, and First Colony Farms alone has over 58,580 ha (145,000 acres) of peat deposits that may be harvested (Campbell 1981). Other large peat deposits occur in the Great Dismal Swamp, the Croatan National Forest, and numerous other interstream pocosins and Carolina bays. With the establishment of a peat-methanol gasification plant in Creswell, North Carolina, the potential use of peat substrates as an energy resource may become more economically attractive. A variety of impacts may result from peat mining in pocosin systems. The land must be drained and cleared as for agri cultural purposes, and subsurface wood must be removed, usually to a depth of 40 cm (16 inches). The land is then graded to a uniform slope (1.5%) to enhance drainage (Campbell 1981). Har vesting is conducted either by a mill .method in which a thin top layer of peat is worked into small particles, allowed to dry and removed with a vacuum harvester, or by digging out the moist peat to a depth of 40 cm (16 inches) and extruding it into cylinders 8 cm (3.2 inches) in diameter and approximately 30 cm (12 inches) long (Campbell 1981; Figure 31). The most significant impact of peat harvesting on pocosins is the loss of natural pocosin habitat and the subsequent effects of this habitat attrition on wild life andxnatural plant communities. It is unlikely that pocosin communities will recover to the natural shrub bog condition in these areas after mining operations are completed. A second major effect of peat mining is a lowering of the substrate surface as a result of removal and from natural sub sidence that results from carbon loss by oxidation during irreversible drying of the surface peat. Lilly (1981a) reported subsidence rates of 2.7 cm/yr (about 1 inch/yr) for the first 2 years and 0.4 to 1.2 cm/yr (up to 0.5 inch/yr) thereafter in eastern North Carolina. With continual harvesting and subsidence, mineral soil that is at or below sea level may eventu ally be exposed. In such cases, continual water level management becomes necessary to maintain the land in a productive state. Such conditions may also allow salt water intrusion into freshwater aqui fers. The required drying of the surface peats increases the probability of a severe burn. In addition, the dried peat granules may contribute to particulate air pollution when winds sweep across the peat fields and may affect water quality in adjacent aquatic habitats (Ash et al., in press). No other extensive mining activities are associated with the Carolina bays per se at this time other than in an agricul tural sense (Figure 30). Sand quarrying, 68 U i\J i M Peat harvester Close-up view of peat extruder Peat pellets after extrusion Figure 31. Peat mining In First Colony Farms, NC, a pocosin habitat. (Photographs courtesy of U.S. Fish and Wildlife Service.) in which the sand rim associated with Carolina bays has been utilized, has been a limited enterprise, but has resulted in major habitat alterations in some in stances. 4.3 CURRENT OWNERSHIP OF POCOSINS AND CAROLINA BAYS Of the 907,933 ha (2,243,550 acres) of pocosin habitat mapped in North Car olina by Wilson in 1962, only about 281,000 ha (695,000 acres) remained in a natural state by 1979 (Richardson et al. 1981; Figure 4). Furthermore, Otte (1981) noted that since Richardson's survey, additional large tracts of pocosin\ have been developed, including areas of the Dismal Swamp peripheral to the Dismal Swamp National Wildlife Refuge, additional areas of the Albemarle-Pamlico peninsula, and many of the Carolina bays in Bladen and Cumberland Counties. Ash et al. (in press) compared the present status of the Green Swamp vegetation with Kologiski's (1977) map based on 1973 aerial photo graphs. They noted extensive ne'wly con verted land, chiefly to loblolly pine plantations. In North Carolina, 48,000 ha (119,000 acres) of pocosin are receiving some degree of protection, either active or passive (Taggart 1981); however, many of these areas had been drained and logged prior to receiving protected status (Richardson et al. 1981). The acreage that is now protected is a low percentage of the original pocosin land in North Carolina. Taggart (1981) listed the major natural pocosin areas of North Carolina. Among the largest of these are the Holly Shelter Game Land (12,000 ha or 30,000 acres) and the Angola Bay Game Land (8,000 ha or 20,000 acres, both managed by the North Carolina Wildlife Resources Com mission; the Croatan National Forest (10,342 ha or 25,284 acres), managed by the. U. S. Forest Service; the Hofmann Forest (6,010 ha or 15,025 acres), owned by Champion International Corporation; and the Green Swamp (5,605 ha or 13,850 acres), managed by The Nature Conservancy. Major timber companies are the larg est pocosin landowners, claiming as much as 44% of pocosin wetlands (Figure 27) although the actua percentage of timber company holdings is not known (Richardson etal. 1981). Large corporate farms (or ^ megafarms) own another 21%. The remaining pocosin land is owned by State and Federal government (18%), various forms of pro tected ownership (5%), and by other land owners (12%), including small, private owners who may be using the land for .various purposes (Richardson et al. 1981). , \-The economic aspects of pocosin man agement (development and preservation) are addressed by Richardson (1982). As he pointed out, different interest groups may value pocosins quite differently. For ex ample, they may be viewed simultaneously as unique natural refuges (to preserva tionists), exploitable game lands (to hunters), valuable potential energy re- sources^to peat mining operations), mar ginal 'to productive lands (to foresters and agriculturalists), wastelands (to in dustry and the uninformed general public), and invaluable ecological resources (to the scientific community). Therefore a consideration of the economic value of these areas requires the impossible as signment of values to nonmarketable com modities such as these natural areas. Present scientific knowledge of the func tion of these wetland ecosystems and their relationship to other components of the ecology of the mid-Atlantic Coastal Plain is far too limited to allow complete and adequate judgment of the worth and impor tance of these systems. However, as Richardson (1982) admonished, if immediate consideration is not given to a management approach that combines ecological and eth ical concerns with economic values, the long-term stability of the southeastern Coastal Plain may be in jeopardy. / 4.4 RECOMMENDATIONS FOR RESEARCH / One of the most informative features of this report has been the revelation^of where research efforts are needed 'to understand the natural shrub bog environ ments and the potential consequences of man-made alterations to them. The speci fic research recommendations that could be made would be endless, but certain general information gaps are readily apparent and can be singled out. 70 Hydro!ogy The hydrodynamics of pocosin areas have been fairly well established in a general sense, but certain components need more thorough investigation if a complete model of the hydrology of these systems is to be developed. One of the areas needing attention is that of water loss through transpiration. Data on transpiration rates of pocosin areas as affected by veg etation type, soil and water table condi tions, precipitation levels, and drainage canals are crucial to completion of a hy drologie model. Evaporation rates under different conditions and at specific localities must also be determined al though regional data are already avail able. Detailed analyses of the impact of drainage canals on water tables and runoff must be pursued in more depth to confirm present models and to answer certain unre solved questions. For example, the rate of lateral movement in peat soils is influenced by several variables such as proximity of ditches, water table level, and level of organics in the soil. Hydro- logic responses should be analyzed under a variety of conditions so that the level of predictability about subsurface water movement can be increased. The hydrology of shrub bogs in Caro lina bays has not been thoroughly investi gated. Certain aspects should differ from those of pocosins because Carolina bays are discrete units rather than being extensive, continuous systems like many pocosin areas. Little is known about fac tors that influence surface water levels or the relationships between subsurface water, precipitation, and above-surface water. This report provides some of the limited data available on what influences water levels in Carolina bays. Detailed studies on specific bays are strongly recommended. i Water Quality and Soil Characteristics Soil composition and characteristics are known for major pocosin areas because of the emphasis on agricultural uses. Only limited soil research has been car ried put, however, on Carolina bays or on pocosins outside of the North Carolina areas of peat mining, crop, and tree farm ing. The collection of basic soil data in shrub bogs throughout the region would be worthwhile in establishing basic environ mental information. Water quality is also known for cer tain pocosin areas and particular Carolina bays, but collection of basic limnological information would be useful. Of particu lar importance is knowledge of the sensi tivity of natural biotic communities to changes in certain water quality parame ters (e.g., pH or phosphate levels) that can be dramatically altered by commercial activities. Research efforts to establish such information should be encouraged. These would include estuarine studies to determine how anadromous fishes and brack ish water organisms are affected by subtle water quality changes resulting from run off through channelized or heavily ferti lized pocosin areas. Biota The most poorly studied and least understood facet of shrub bog communities of the Atlantic Coastal Plain is the basic biology. Vegetational analyses have been carried out in both habitats, particularly in the pocosins, but plant studies in Car olina bays have been few. Regional analy ses of vegetational variation among these and related wetlands with a strong focus on the relationship of vegetation pattern to various environmental features (e.g., soil type, moisture levels, and recent land use history) would provide a funda mental understanding of the range of botanical variation in these habitats. Practically no faunal studies have been made on pocosins as an identifiable habi tat and very few in-depth studies have been undertaken of animals in Carolina bays. In fact, the original data from the Savannah River Plant presented in this report are the most extensive quantitative information collected in such habitats. Besides the limited research on basic pop ulation phenomena, species diversity and composition, and structural and functional characteristics of the biotic communities, few studies have posed ecological ques tions related to the qualities and charac teristics of shrub bogs: for example, how the community responds, collectively and through its individual species, to the low-nutrient conditions, the low pH, or 71 the annual and seasonal fluctuations in water level. Fire The effects and long-term environ mental consequences of fire in shrub bog areas are poorly understood even though certain ecological impacts are apparent. Prescribed burning is being used on a more frequent basis to control wildfire danger and to prepare sites for various manage ment activities. Little quantitative information, however, is available on the short- or long-term effects of such fires on vegetational composition and productiv ity, nutrient releases into the soil or atmosphere, water quality, or rates of peat accumulation. Research in areas where prescribed burning is carried out would provide general information on fire ecology in these ecosystems and give a basis for understanding the influence and importance that natural fires have had on shrub bog communities. Recommendations Recommending ecological studies asso ciated with a topic can be open-ended, but the following seem to be essential re search efforts that should be undertaken at this time: 1. As a first priority, basic lists, relative population sizes, and extent of utilization by the animal species associated with pocosins and Carolina bays need to be established. The vegetational component of the shrub -- bog community has been documented (although inadequately) but knowledge of pocosin fauna is exceptionally scanty. Information on Carolina bay fauna is limited in the scientific literature. This fundamental aspect of needed research on shrub bogs should be strongly encouraged and supported by State and Federal agen cies that oversee these natural wet- ^ lands and by private enterprises that cause an environmental impact to them. 2. Plant ecology of Carolina bays is poorly known. Questions should be asked of whether geographic changes occur in vegetational aspects or how certain variables, such as size of the depression or moisture levels, influence the vegetation. Natural succession of pocosins and Carolina bays is poorly understood bqth spat ially and temporally. Intensive re search efforts are recommended to address these botanical issues. 3. The interaction among plants and ani mals within the shrub bog ecosystem and between that system and other natural ecosystems is a key aspect of having an understanding of the biol ogy of a region. The drift fence studies with small vertebrates on the Savannah River Plant have revealed the unsuspected importance of Caro lina bays to transient and resident animal species. Studies in pocosin habitats might reveal a similar im portance. Although the basic studies mentioned above are strongly recom mended immediately, in-depth and long-term studies of biotic interac tions and dependencies should also be initiated. 4. Certain non-biotic forces have a critical influence on the biological character of these ecosystems. Basic research directed toward quantita tively establishing how the timing and intensity of either fire or pre cipitation influence key community processes such as primary productiv ity and elemental cycling would be extremely valuable in understanding shrub bog ecosystems. 5. Studies of natural succession in pocosins and Carolina bays would pro vide a much-needed understanding of the evolution of communities in these ecosystems. Such studies could be carried out through the initiation of long-term research at particular lo calities, through soil profile analy ses, or possibly through a careful study of aerial photographs from pre scribed habitats. Natural succession in these communities has not been investigated in sufficient depth for conclusive statements to be made about this process. i - ; All of the basic, fact-finding re search needed will be directly applicable 72 to the environmental problems associated with these ecosystems. Only by acquiring these fundamental data for natural systems can we begin to assess the environmental impact that man-caused alterations have had or will have on them. Furthermore, such studies are necessary to establish a value system for the preservation of eco logically important pocosins and Carolina bays throughout the southeastern Atlantic Coastal Plain. 73 CHAPTER 5 RECOMMENDATIONS FOR CONSERVATION, PRESERVATION AND MANAGEMENT Making management recommendations for a general community type is a difficult, if not futile task, especially when the community type spans a major part of sev eral States so that a wide variety of regional habitats are encountered as well as different economic and land management' strategies, and differing legal restric tions. Thus, an approach that is prudent and applicable in one area may be totally inappropriate in another. Today many pocosin areas are being developed as pine plantations, farms, and potential peat mines. However, development and preserva tion are not always incompatible. There are many cost-effective options that will let commercial enterprise and wildlife exist in harmony (Ash et al., in press). A more complete and detailed treatment of development options and recommendations is given by Ash et al. (in press). In a most generalized sense, certain conclusive statements and recommendations can be made on how to enhance the future well-being of shrub bog communities of the Atlantic seaboard as follows: Increase Ecological Research The level of ecological information about these communities and their impor tance to fauna and flora of a region is presently inadequate to assess their over all importance to southeastern ecosystems. Coupled with this dearth of understanding of the natural communities of plants and animals that inhabit or are transients to such areas is the limited information on water chemistry and the specifics of soil conditions and hydrology. Although such information is satisfactorily known for certain prescribed areas or particular habitats, wide-ranging comparative studies are non-existent and long-term studies are woefully few. The first recommendation, therefore, is that extensive and intensive ecological studies need to be encouraged by appropriate agencies to investigate pocosins and Carolina bays in an in-depth manner that will provide the information necessary. Ecological research should not be restricted to a single approach (e.g., ecosystem, population), but should use a wide variety of studies to understand better not only the structure and func tion of the systems but also the basic natural/hi story of the habitats. Protect Critical Habitats Because of the vulnerability of poco sin and Carolina bay habitats to many forms of land management including fores try practices, agriculture, urbanization, and peat mining, a strong program of habi tat protection needs to be developed. This can be accomplished in part through the protection offered by National Parks or by State and National Forests. In add ition, some sites receive passive protec tion by virtue of being on private lands that do not have activities that jeopar dize the integrity of the natural habi tats. However, Otte (1981) noted that essentially all the smaller pocosins in North Carolina are altered to the point that they may not be salvagable as natural wetlands. Some of the larger ones are provided some protection by the Federal government (e.g., Croatan National Forest, Dismal Swamp National Wildlife Refuge, and Dare County Bombing Range); by the State (e.g., Bladen Lakes ^State Forest); or by private ownership (e.g., The Green Swamp Nature Conservancy). Even so, since 1979 a number of pocosin areas in North Caro lina have been partly or totally devel oped, including large tracts of land along the Alligator River in Dare and Tyrrell Counties, the Bay City Pocosin and Gum Swamp in Pamlico and Beaufort Counties, the Light Ground Pocosin in Pamlico County, and unprotected portions of the 74 Green Swamp in Brunswick and Columbus Counties (Otte 1981). Although there are still pocosins and Carolina bays remaining in a natural state, an active program of protection needs to be developed at this time at both public and private levels. This can come through formulating wetlands legislation to protect both Carolina bays and pocosins as natural wetlands and by means of vari ous land management incentives to protect such areas. " Development of a program directed toward private land owners that gives appropriate credit for actively pro tecting pocosin or Carolina bay wetlands might be an incentive to some individuals. Tax incentives by State and Federal gov ernments could be established in the pri vate sector in a manner that would effec tively contribute to habitat protection. A judicious approach to habitat use should be instituted at least until appropriate research can be carried out to determine the importance of these habitats to re gional flora and fauna. Develop Region-Specific Management Schemes Specific restrictions and constraints should be placed on particular geographic areas where problems are apparent. For example, potential peat mining should be limited in areas of North Carolina where hundreds of square miles per year could be heavily affected by such activities. One of the major problems affecting both pocosins and Carolina bays is lowering of the water table. This, of course, is a regional, perhaps a national, problem that needs to be addressed. These rainfall- dependent ecosystems are severely affected by reduced water tables. A continued reduction in water tables will ultimately lead to the elimination of many of the smaller, shallower Carolina bays and to a large portion of pocosin habitat. Local consideration must be given to the best approaches that should be taken in pro tecting each of these wetland types. A pocosin-related problem concerns impact of runoff in estuarine systems, such as the Pamlico-Albemarle Sound area. Thus, inland activities may have to be restricted or controlled in some manner because of the actual or potential effects on contiguous ecosystems. The most appropriate regional management scheme to implement such pro grams would need to be agreed upon by the various Federal, State, and local agencies concerned with a particular region. Increase Public Awareness A major problem in developing an environmental protection attitude about pocosins and Carolina bays is that most laymen are uninformed about them. Many people are unaware of Carolina bays in areas, even where densities are. moderate (1 bay/2 mi2) because the habitats have been altered to a level where they are no longer recognized as wetland ecosystems or because distinctiveness of Carolina bays as natural wetlands has not been pointed out. A common attitude among inhabitants of pocosin regions is that they are waste land areas. Knowledge of the biota and of the hydrological regime is generally mini mal. Ecologists themselves know little about the dependency of wildlife on poco sin and Carolina bay habitats, although the limited information available suggests they are vital to the livelihood of some species in certain areas or environmental situations. Because professional ecologists and environmental managers are limited in their knowledge of these ecosystems, the transfer of information to the public is diminished even further. A major public education effort needs to be made at this time about the presence, the values, and the rapid rate of disappearance of these natural wetlands. An uninformed public cannot be expected to develop sympathetic attitudes toward the inexorable decline of these wetland systems. Professional ecol ogists and various agencies and institu tions can be considered responsible for the conduct of appropriate research and the transmittal of scientific information about shrub bogs. Additionally, these groups must accept the charge of assuring public awareness of the value of these ecosystems and of the environmental prob lems they presently face. 75 REFERENCES Ash, A.N., C.B. McDonald, C.A. Pories, and E.S. Kane. (In press.) Natural and modified pocosins: literature syn- - thesis and management options for fish and wildlife. Contract No. 14-16-0009-81-057. U.S. Fish and Wildlife Service. National Coastal Ecosystems Team, Slidell, La. Ashton, R.E., Jr. 1981. Interpretation of pocosins in North Carolina: the state of the art. Pages 183-188 jn. C.J. Richardson, ed. Pocosin wet lands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Atlantic Coast Ecological Inventory. Florence, S.C.-N.C. 1980. 1:250,00 map. U.S. Fish and Wildlife Service, Washington, D.C. 34078-A1-E1-250. Available from U.S. Geological Sur vey, Reston Va. Atlantic Coast Ecological Inventory. James Island, South Carolina. 1980. 1:250,000 map. U.S. Fish and Wild life Service, Washington, D.C. 32078-A1-E1-250. Available from U.S. Geological Survey, Reston, Va. Atlantic Coast Ecological Inventory. Man- teo, North Carolina. 1980. 1:250,000 map. U.S. Fish and Wildlife Service, Washington, D.C. 35074-A1-E1-250. Available from U.S. Geological Sur vey, Reston, Va. Atlantic Coast Ecological Inventory. Rocky Mount, North Carolina. 1980. 1:250,000 map. U.S. Fish and Wild life Service, Washington, D.C. 35076-A1-E1-250. Available from U.S. ^ Geological Survey, Reston, Va. Bailey, J.R., and D.G. Frey. 1958. Dart ers of the genus Hololepis from some natural lakes of North Carolina. J. Elisha Mitchell Sei. Soc. 67:191-203. Barber, R.T., and W.W. Kirby-Smith. 1975. Data report no. 1. Water quality ramifications of converting forest to intensive agriculture. Duke Univer sity Marine Laboratory, "Beaufort, N.C. 63 pp. Barber, R.T., and W.W. Kirby-Smith. 1976. Data report no. 2. Water quality ramifications of converting forest to intensive agriculture. Duke Univer sity Marine Laboratory, Beaufort, N.C. 38 pp. Barber, R.T., W.W. Kirby-Smith, and P.E. Parsley. 1979. Wetland alterations for agriculture. Pages 642-651 in P.E. Greeson, J.R. Clark, and J.E. Clark, eds. Wetland functions and values: the state of our understand ing. Proceedings of the National Symposium on Wetlands, Lake Buena Vista, Fla. Nov. 1978. American Water Resources Association.— Barkalow, F.S., Jr. 1979. Bobwhite quail (Colinus virgi'nianus) foods in poco- sTTihabitat converted to pine. J. Wild!. Manage. 43:516-521. Barnes, J.S. 1981. Agricultural adapta bility of wet soils of the North Carolina coastal plain. Pages 225- 237 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa.^ Barnes, R.L., and A.W. Naylor. 1959. Effect of various nitrogen sources on growth of isolated roots of Pinus serotina. Physiol. Plant. 12:82-89. Barringer, B. 1944. Observations on the Carolina "craters" or "bays." Pop. Astron. 55:215-217; Meteor Soc. Contr. 4:33-35. / Baxter, J., and T. Atkins. 1976. The fire came by. Doubleday & Co., Inc., New York. / Beccasio, H.D., G.H. ' Weissbergy, A.E. Redfield, et al. 1980. Atlantic coast ecological inventory: user's guide and information base. U.S. Fish and Wildlife Service, Biological Services Program, Washington, D.C. (FWS/OBS-80-51). 163 pp. + maps. Bennett, D.H. 1972. Notes on the ter restrial wintering of mud turtles (Kinosternon subrubrum). Herpeto- logica 28:245-247. Bennett, D.H., J.W. Gibbons, and J.C. Franson. 1970. Terrestrial activity in aquatic turtles. Ecology 51: 738-740. Bennett, S.H., J.W. Gibbons, and J. Glan- ville. 1979. Terrestrial activity, abundance and diversity of amphibians in differently managed forest types. Am. Midi. Nat. 103:412-416. Blair, W.F., A.P. Blair, P. Brodkorb, F.R. Cagle, and G.A. Moore. 1968. Verte brates of the United States. McGraw- Hill Book Co., New York. Bliley, D.J., and D.E. Pettry. 1979. Carolina bays on the eastern shore of Virginia. Soil Sei. Soc. Am. J. 43:558-564. Boelter, D.H., and E.S. Verry. 1977. Peatland and water in the northern Lake states. USDA For. Serv. Gen. Tech. Rep. NC-31, N. Cen. For. Exp. Stn., St. Paul, Minn. 22 pp. Boyce, S.G., and N.D. Cost. 1974. Timber potentials in the wetland hardwoods. Pages 130-151 jm M.C. Blount, ed. Water resources,, utilization, and conservation in the environment. Taylor Printing Co., Reynolds, Ga. Braun, E.L. 1950. Deciduous forests of Eastern North America. Hafner Pub lishing Co., New/ York. 596 pp. Briese, L. A., and M. H. Smith. 1974. Seasonal abundance and movement of nine species of small mammals. J. Mammal. 55:615-629. Brinson, M.M. 1980. Section I - Ecolog ical and geological overview. Pages 1-28 \n_ P.H. Fricke, M.M. Brinson, and W.N. Still. Croatan National Forest: a socioeconomic overview. Tech. Rep. from East Carolina Univer sity, Greenville, N.C., for the U.S. Forest Service. Contract No. OM-43- 4550-8-241. 159 pp. Brower, D.J., and N.D. Noneman. 1981. The formulation of a management plan for pocosins in .coastal North Caro lina. Pages 318-333 j_n C.J. Richard son, ed. Pocosin wetlands. Hutchin-y son Ross Publ. Co., Stroudsburg, Pa. Brown, K.W. 1980. An analysis of herpe- tofaunal species diversity along a temporal gradient of loblolly pine stands in South Carolina. Master's Thesis. Texas Christian University, Fort Worth, Tex. Brown, W. 1911. Plant life of Ellis, Great, Little and Long Lakes in North Carolina. Contrib. U. S. Natl. Herb. 13:323-341. Bryant, J.P. 1964. Soils of the Carolina bays and interbay areas in Scotland County, North Carolina. Ph.D. The sis. North Carolina State Univer sity, Raleigh. 256 pp. Bryant, J.P., and R.J. McCracken. 1964. Properties of soils and sediments of the Carolina bays. J. Elisha Mitchell Sei. Soc. 80:166. Buckman, H.O., and N.C. Brady. 1969. The nature and properties of soils. The MacMillan Co., New York. Buell, M.. 1939a. Peat formation in the Carolina bays. J. Elisha Mitchell Sei. Soc. 55:244-245. Buell, M.F. 1939b. Peat formation in the Carolina bays. Bull. Torrey Bot. Club 66:483-487. Buell, M.F. 1945. Late Pleistocene forests of southeastern North Caro lina. Torreya 45:117-118. Buell, M.F. 1946a. Jerome Bog, a peat- filled "Carolina bay." Bull. Torrey Bot. Club 73:24-33. Buell, M.F. 1946b. The age of Jerome Bog, "a Carolina bay." Science 103:14-15. 76 77 Buell, M.F., and R.L. Cain. 1941. A bog community in southeastern North Caro lina. J. Elisha Mitchell Sei. Soc. 57:202. Buell, M.F., and R.L. Cain. 1943. The successional role of southern white cedar, Chamaecyparis thyoides, in southeastern North Carolina. Ecology 24:85-93. Burt, W.H., and R.P. Grossenheider. 1976. A field guide to mammals. Houghton Mifflin Co., Boston, Mass. Burton, T.M., and G.E. Likens. 1975. Energy flow and nutrient cycling in salamander populations in the Hubbard Brook Experimental Forest, New Hamp shire. Ecology 56:1068-1080. Campbell, R.G., and J.H. Hughes. 1981. Forest management systems in North Carolina pocosins. Pages 199-213 in C.J. Richardson, ed. Pocosin wet lands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Campbell, R.N., Jr. 1981. Peat for energy program: First Colony Farms, Inc. Pages 214-224 in C.J. Richard son, ed. Pocosin wetTands. Hutchin son Ross Publ. Co., Stroudsburg, Pa. Carter, L.J. 1975. Agriculture: a new frontier in coastal North Carolina. Science 189:271-275. Caughey, M.G. 1943. A physiological and ecological study of certain pocosin plants. Ph.D. Thesis. Duke Univer sity, Durham, N.C. Christensen, N.L. 1976. The role of car- nivory in Sarracenia flava L. with regard to specific nutrient deficien cies. J. Elisha Mitchell Sei. Soc. 92:144-147. Christensen, N.L. 1977a. Fire and soil- "*"" plant nutrient relations in a pine- wire grass savanna on the coastal plain of North Carolina. Oecologia 31:27-44. Christensen, N.L. 1977b. Fire in south ern forest ecosystems. In Symposium: fire by prescription. USDA Forest Service, Atlanta, Ga. Christensen, N.L. 1979. Shrublands of the Southeastern United States. Pages 441-449 jn_ R.L. Specht, ed. Heathlands and related shrublands of the world, A. Descriptive studies. Elsevier, Amsterdam. Christensen, N.L. 1980. Fire regimes in southeastern ecosystems. In H.A. Mooney, T. Bonnicksen, N.L. Christen sen, W.A. Reiners and J. Lotan, eds. Fire regimes and ecosystem proper ties. USDA Forest Service, Gen. Tech. Rep., Washington, D.C. Christensen, N.L., R.B. Burchell, A. Liggett, and E.L. Simms. 1981. The structure and development of pocosin vegetation. Pages 43-61 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Strouds burg, Pa. Coastal Plains Center for Marine Develop ment Services. 1974. Protected sites in the Carolinian classification- Cape Hatteras to Cape Kennedy. Wilmington, N.C. Coastal Zone Resources Corporation. 1975. A preliminary environmental appraisal of the Open Grounds Farm, Inc., agri cultural development. Coastal Zone Resources Corporation, Wilmington, N.C. ' Coastal Zone Resources Corporation. 1976. Environmental assessment of First Colony Farms agricultural development in Dare, Tyrrell, Hyde, and Washing ton Counties,,North Carolina. Coastal Zone Resource's Corporation, Wilming ton, N.C. Coker, -W.C. 1928. The distribution of Dionaea muscipula. J. Elisha Mitchell Sei. Soc. 43:221-228. Conant, R. 1975. A field guide to rep tiles and amphibians of Eastern and Central North America. Houghton Mifflin Co. Boston, Mass. 429 pp. Cooke, C.W. 1933. Origin of the so-called meteorite scars of South Carolina. J. Wash. Acad. Sei. 23:569-570. Cooke, C.W. 1934. Discussion of the ori gin of the supposed meteorite scars 78 of South Carolina. 88-104. J. Geol. 42: Cooke, C.W. 1940. Elliptical bays in South Carolina and the shape of eddies. J. Geol. 48:205-211. Cooke, C.W. 1943a. Elliptical bays. J. Geol. 51:419-427. Cooke, C.W. 1943b. Discussion of The Origin of the Carolina Bays . by D.W. ~ 5cT. 241:583-589. Origin o Johnson. Cooke, C.W. 1945. Neptune's race track. Sei. Monthly 60:286-291. Cooke, C.W. 1950. Carolina bays, traces of tidal eddies. Geol. Soc. Am. Bull. 61:1452. Cooke, C.W. 1954. Carolina bays and the shapes of eddies. U.S. Geological Service Prof. Pap. 254-1, pp. 195- 206. Cooke, C. W. 1956. Discussion of "Were the Carolina bays oriented by gyro scopic action?" by W. Schriever. Trans. Am. Geophys. Union 37:115-116. Cooper, A. W. 1981. A policy for pocosin preservation. Pages 334-341 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ., Co., Strouds-| burg, Pa. Cooper, J.E., S.S. Robinson, and J.B. Funderburg, eds. 1977. Endangered and threatened plants and animals of North Carolina. North Carolina Museum of Natural History, Raleigh. Copeland, B.J., and R.G. Hodson. 1982. Estuarine profile of Albemarle Sound. U. S. Fish and Wildlife Service, Bio logical Services Program, Washington, D.C. FWS/OBS- Draft. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. FWS/OBS- 79/31, U.S. Fish and Wildlife Service, Office Biological Services, Habitat Preservation Program, Washington, D.C. 103 pp. Cronin, T.M., B.J. Szabo, T.A. Ager, J.E. Hazel, and J.P. Owens. 1981. Qua ternary climates and sea levels of the U. S. Atlantic Coastal Plain. Science 211:253-240. Dabei, C.W., and F.P. Day, Jr. 1977. Structural comparisons of four plant communities in the Great Dismal Swamp, Virginia. Bull. Torrey Bot. Club 104:352-360. Dachnowski-Stokes, A.P., and B.W. Wells. 1929. The vegetation, stratigraphy, and age of the "open land" peat area in Carteret County, N.C. J. Wash. Acad. Sei. 19:1-11. Daniel, C.C., III. 1978. Land use, land cover and drainage on the Albemarle- Pamlico peninsula, eastern North Carolina, 1974. Water Resources Inv. No. 78-134. U.S. Geological Survey, Raleigh, N.C. Daniel, C.C., III. 1981. Hydrology, geology, and soils of pocosins: a comparison of natural and altered systems. Pages 69-108 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Strouds burg, Pa. ^- Daniels, R.B., E.E. Gamble, and C.S. Holzhey. 1975a. Thick BH horizons in the North Carolina coastal plain: I & II. Proc. Soil Sei. Soc. Am. 38:1177-1187. Daniels, R.B., J.W. Gilliam, E.E. Gamble, and R.W. Skaggs. 1975b. Nitrogen movement in a shallow aquifer system of the North Carolina coastal plain. Water Resour. Bull. 11:1121-1130. Daniels, R.B., E.E. Gamble, W.H. Wheeler, and C.S. Holzhey. 1977. The strati graphy and geomorphol ogy of the Hofmann Forest pocosin. J. Soil Sei. Soc. Am. 41:1175-1180. Darnel 1, R.M. 1976. Impacts of construc tion activities in wetlands of the United States. U.S. Environmental Protection Agency Ecological Research Series. EPA-600/3-76-045. xxvii + 392 pp. 79 Darnell, R.M. 1978. Overview of major development impacts on wetlands. Pages 19-27 jm Proceedings of the National Wetland Protection Sympo sium, June, 1977, Reston, Va. FWS/ OBS-78/97. GPO No. 024-010-00504-1. Supt. of Doc., Gov. Print. Office, Washington, D.C. 20402. Dean, G.W. 1969. Forests and forestry in . the Dismal Swamp. Va. J. Sei., N. S. 20:166-173. Dideriksen, R.I., A.R. Hidlebaugh, and K.O. Schmode. 1979. Wet soils for crop production in the United States. Pages 632-641 rn_ P.E. Greeson, J.R. Clark, and J.E. Clark, eds. Wetland functions and values: the state of our understanding. Proceedings of the National Symposium on Wetlands, Lake Buena Vista, Fla, Nov. 1978., American Water Resources Association. Dolman, J.D., and S.W. Buol. 1967. A study of organic soils (histosols) in the tidewater region of North Caro lina. N.C. Ag. Exp. Stn. Tech. Bull. No. 181. Doucette, W.H. 1980. Coastal land drain age for agriculture and forestry. Center for Rural Resource Develop ment, North Carolina State Univer sity, Raleigh. Doucette, W.H., Jr., and J.A. Phillips. 1978. Overview: agriculture and forest land drainage in North Caro lina's coastal zone. Center for Rural Resource Development Report No. 8, North Carolina State Univer sity, Raleigh. Echelle, A.A., and D.T. Mosier. 1981. All-female fish: a cryptic species of Menidia (Antherinidae). Science 212:1411-1413. Emmons, E. 1860. The swamp lands of North Carolina. N.C. Geological Survey, Part II, Agriculture. Raleigh, N.C. Engineer Agency for Resource Inventories. 1978. Environmental reconnaissance inventory of the State of North Caro lina. U.S. Department of the Army, Office of the Chief of Engineers, Fort Bel voir, Va. Ernst, C.H., and R.W. Barbour. 1972. Turtles of the United States. Uni versity Press of Kentucky, Lexington. 347 pp. Esch, G.W., J.W. Gibbons, and J.E. Bour- que. 1979a. The distribution and abundance of enteric helminths in Chrysemys s.. scripta from various habitats on the~Savannah River Plant in South Carolina. J. Parasitol. 65:624-632. Esch, G.W., J.W. Gibbons, and J.E. Bour- que. 1979b. Species diversity of helminth parasites in Chrysemys s_. scripta from a variety of habitats in South Carolina. J. Parasitol. 65:633-638. S Eyton, J.R., and J.I. Parkhurst. 1975. A re-evaluation of the extra-terres trial origin of the Carolina bays. Occasional Publ. Dep. Geogr., Pap. No. 9, University of Illinois at Urbana-Champaign. 47 pp. Fairchild, L. 1981. Mate selection and behavioral thermorégulation in Fowl er's toads. Science 212:950-951. Farnsworth, E.G., M.C. Nichols, C.N. Vann, L.G. Wolfson, R.W. Bosserman, P.R. Hendrix, F.B. Golley, and J.L. Cooley. 1979. Impacts of sediment and nutri ents on biota in surface waters of the United States. EPA-600/379-104, NTIS, Springfield, Va. 315 pp. Ferguson, J.L. 1943. Discussion of Thje Origin of the Carolina Bays, by D.W. Johnson. AüüÄssöc. Petrol. Geol. Bull. 27:654-656; correction, 27:874. Fetter, C.W., Jr. 1973. Water resources management in coastal plain aquifers. Pages 322-331'in Water for the human environment, VôT. 1, Congress Papers: Proceedings of the First World Con gress on Water Resources, Chicago, Illinois, Sept. 1973. International Water ' Resources Association, Cham paign, 111. / Folkerts, G.W. 1982. The gulf coast pitcher plant bogs. Am. Sei. 70: 260-278. Fowells, H.G. 1968. Si Ivies of forest trees of the United States. U.S. Department of Agriculture, Agricul ture Handbook No. 271. 762 pp. Fowler, H.W. 1942. Descriptions of six new freshwater fishes (Cyprinidae and Percidae) from the Southeastern Unit ed States. Acad. Nat. Sei. Phila delphia, Notulae Naturae 107:1-11. Fredine, G.C., and S.P. Shaw. 1971. Wet lands of the United States: their ex tent and their value to waterfowl and other wildlife. U.S. Fish and Wild life Service, Circ. 39. Government Printing Office, Washington, D.C. Frey, D.G. 1948a. Lakes of the Carolina bays as biotic environments. N.C. Acad. Sei. Proc. J. Elisha Mitchell Sei. Soc. 64:179. Frey, D.G. 1948b. North Carolina's bay lakes. Wildl. N.C. 12:10-17. Frey, D.G. 1949. Morphometry and hydro graphy of some natural lakes of the North Carolina coastal plain: the bay lake as a morphometric type. J. Elisha Mitchell Sei. Soc. 65:1-37. Frey, D.G. 1950. Carolina bays in rela tion to the North Carolina coastal plain. J. Elisha Mitchell Sei. Soc. 66:44-52. Frey, D.G. 1951a. The fishes of North Carolina's bay lakes and their intraspecific variation. J. Elisha Mitchell Sei. Soc. 67:1-44. Frey, D.G. 1951b. Pollen succession in the sediments of Singletary Lake, North Carolina. Ecology 32:518-533. Frey, D.G. 1953. Regional aspects of the late-glacial and post-glacial pollen succession of southeastern North Carolina. Ecol. Monogr. 23:289-313. Frey, D.G. 1954. Evidence for the recent enlargement of the "bay lakes' of North Carolina. Ecology 35:78-88. Frey, D.G. 1955a. Stages in the ontogeny of the Carolina bays. Int. Assoc. Theor. App. Limnol. Proc. 12:660-668. Frey, D.G. 1955b. A time revision of the Pleistocene pollen chronology of southeastern North Carolina. Ecology 36:762-763. Frink, J.W., and G.E. Murray, Jr. 1937. Elliptical "bays" or "craters" of Southeastern United States. The Compass, Sigma Gamma Epsilon 17: 227-233. Fuller, S.L.H. 1977. Freshwater and ter restrial molluscs. Pages 143-194 jn J.E. Cooper, S.S. Robinson, and J.B. Funderburg, eds. Endangered and threatened plants and animals of North Carolina. North Carolina State Museum of Natural History, Raleigh. Gamble, E.E., R.B. Daniels, and W.H. Wheeler. 1977. Primary and secondary rims of Carolina bays. Southeast. Geol. 18:199-211. Gambrell, R.P., J.W. Gilliam, and S.B. Weed. 1974. The fate of fertilizer nutrients as related to water quality in the North Carolina coastal plain. Rep. No. 93, WRRI, North Carolina State University, Raleigh. Garren, K.H. 1943. Effects of fire on vegetation of the Southeastern United States. Bot. Rev. 9:617-654. Gibbons, J.W. 1969. Ecology and popula tion dynamics of the chicken turtle, Deirochelys reticularia. Copeia 1969:669-676. Gibbons, J.W. 1970. Terrestrial activity and the population dynamics of aquatic turtles. Am. Midi. Nat. 83:404-414. Gibbons, J.W., and J.W. Coker. 1977. Ecological and life history aspects of the cooter, Chrysemys floridana (Le Conte). Herpetölogica 33:29-33. Gibbons, J.W., and J.L. Greene. 1978. Selected aspects of the ecology of the chicken turtle, Deirochelys reticularia (Latreille) (Reptilia, 80 81 Testudines, Emydidae). J. Herpetol. 12:237-241. Gibbons, J.W., and D.H. Nelson. 1978. The evolutionary significance of delayed emergence from the nest by hatchling turtles. Evolution 32:297-303. Gibbons, J.W., and R.D. Semlitsch. 1982. Terrestrial drift fences with pitfall traps: an effective technique for quantitative sampling of animal popu lations. Brimleyana. (In press). Gibbons, J.W., D.H. Nelson, K.K. Patter- son, and J.L. Greene. 1976. The reptiles and amphibians of the Savannah River Plant in west-central South Carolina. In D. N. Forsythe and W. B. Ezell, Jrl, eds. Proceed ings of the First South Carolina Endangered Species Symposium. South Carolina Wildlife and Marine Re sources Dep., Columbia. Gibbons, J.W., J.W. Coker, and T.M. Mu*1- phy, Jr. 1977. Selected aspects of the life history of the rainbow snake (Farancia erytrogramma). Herpetolog- ica 33:271-281. Gibbons, J.W., J.L. Greene, and J.P. Schu- bauer. 1978. Variability in clutch size in aquatic chelonians. Br. J. Herpetol. 6:13-14. Gibbons, J.W., R.D. Semlitsch, J.L. Greene, and J.P. Schubauer. 1981. Variation in age and size at matu rity of the slider turtle (Pseudemys scripta). Am. Nat. 117: 841-845. Giese, G.L., A.B. Wilder and G.G. Parker. 1979. Hydrology of major estuaries and sounds of North Carolina. (Water Resources Inventory 79-46), U.S. Geo logical Survey, Raleigh, N.C. Gillian, J.W., and R.W. Skaggs. 1981. "^Drainage and agricultural develop ment: effects on drainage waters. Pages 109-124 in_ C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Gleason, H.A. 1963. The new Britton and Brown illustrated flora of the North eastern United States and adjacent Canada. 3 vols. Hafner Publ. Co., New York. Glenn, L.C. 1895. Some notes on Darling- . ton (South Carolina) "bays." Science 2:472-475. Goldsmith, V. 1973. Internal geometry and origin of vegetated coastal sand dunes. J. Sediment. Petrol. 43:1128- 1142. Graham, B.F., Jr., and A.L. Rebuck. 1958. The effect of drainage on the estab lishment and growth of pond pine (Pinus serotina). Ecology 39:33-36. Grant, C. 1945a. "When the comet struck America" vs. "Neptune's racetracks." Sei. Monthly 61:243. Grant, CC 1945b. A biological explana tion of the Carolina bays. Sei. Monthly 61:443-450. Grant, C. 1948. Meteoritic origin of the "Carolina bays" questioned. Pop. Astron. 56:511-527. Greeson, P.E., J.R. Clark, and J.E. Clark eds. 1978. Wetland functions and values: the state of our understand ing. American Water Resources Asso ciation, Minneapolis, Minn. Hamilton, W.J. 1943. The mammals of Eastern United States. Comstock Publ. Co., Inc., Ithaca, N.Y. Hamilton, R.J., and R.L. Marchinton. 1977. Denning and related activity of black bears in the coastal plain of North Carolina. In Bears, their biology and management. Bear Biol. Assoc. Conf., Ser. No. 3. Hardin, J.W. 1977. Vascular plants. Pages 56-131 in ' J.E. Cooper, S.S. Robinson, and "71 B. Funderburg, eds. Endangered and, threatened plants and animals of North Carolina. North Carolina State Museum of Natural History, Raleigh. Harper, R.M. 1907. A midsummer journey through the coastal plain of the Carolinas and Virginia. Bull. Torrey Bot. Club 34:351-377. 82 Harrison, W., R.J. Malloy, G.A. Rusnak, and J. Terasmae. 1965. Possible late Pleistocene uplift, Chesapeake Bay entrance. J. Geol. 73:201-229. Hartshorn, G.S. 1972. Vegetation and soil relationships in southern Beau fort County, North Carolina. J. Elisha Mitchell Sei. Soc. 88:226-238. Harwood, H.J., and P.S. McMullan, Jr. 1981. Peat energy for North Caro lina: an economic analysis. Pages 255-269 jn. C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Hawley, A.J. 1974. The present and future status of eastern North Caro lina wetlands. (Rep. No. 87), WRRI, North Carolina State University, Raleigh. Hazel, D.W. 1977. Deer browse production associated with the practice of site conversion in a North Carolina poco- sin. M.S. Thesis. North Carolina State University, Raleigh. Heath, M.S., Jr. 1981. Political economy of alternative management strategies for pocosins in North Carolina. Pages 305-317 j£ C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Heath, R.C. 1975. Hydrology of the Albemarle-Pamlico region of North Carolina: a preliminary report on the impact of agricultural develop ments. (Water Resources Inv. 75-9), U.S. Geological Survey, Raleigh, N.C. Hobbie, J.E. 1970. Phosphorus concentra tions in the Pamlico River estuary of North Carolina. Rep. No. 33. Water Resources Research Institute of Uni versity of North Carolina, Raleigh. Hough, W.A. 1969. Caloric values of some forest fuels of the Southern United States. U.S. Department of Agricul ture Forest Service Res. Note, SE-120. Southeastern For. Exp. Stn., Asheville, N.C. 6 pp. Hubbs, C.L., and E.C. Raney. 1946. En demic fish fauna of Lake Waccamaw. Univ. Mich. Mus. Zoo!. Misc. Publ. 65:1-30. Huck, R.B. 1978. Flora, vegetation and soils of the Bull Creek Watershed, Osceola County, Florida. Master's Thesis. University of North Carolina, Chapel Hill. Hueske, E.E. 1948. Fish resources of the bay lakes. Wildl. N.C. 12:4-6, 17-19. Hufschmidt, M.M. 1980. State water resource planning and policy in North Carolina. Water Resources Research Institute, University of North Caro lina, Raleigh. Rep. No. UNC-WRRI- 79-143. 134 pp. Hutchinson, G.E. 1944. The Carolina bays. Am. Sei. 32:80. Ingram, H.A.P. 1967. Problems of hydrol ogy and plant distribution in mires. J. Ecol. 55:711-724. Ingram, R.L., and L.J. Otte. 1981a. Peat deposits of Croatan Forest, Craven, Jones and Carteret Counties, North Carolina. (Contract No. DE-AC01- 79ET-14693), U.S. Department of Energy, North Carolina Energy Insti tute. Ingram, R.L., and L.J. Otte. 1981b. Peat in North Carolina wetlands. Pages 125-134 jji C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Johnson, D. 1934. Supposed meteorite scars of S. C. Science 79:461. Johnson, D.W. 1936. Origin of the sup posed meteorite scars of Carolina. Science 84:15-18. Johnson, D.W. 1937. Role of artesian waters in forming the Carolina bays. Science 86:255-258. Johnson, D. 1941a. Rotary currents and the Carolina bays. J. Geomorph. 4:164-166. Johnson, D.W. 1941b, 1942a. Rotary currents and the Carolina bays. J. 83 Geomorph. 4:307-321; conclusion, v. 5:59-72. Johnson, D.W. 1942b. The origin of the Carolina bays. Columbia University Press, New York. 341 pp. Johnson, D.W. 1943. Reply to "Discussion of The Origin of the Carolina Bays by D. W. Johnson11" by J"!Ü".Ferguson. Am. Assoc. Petrol. Geol. Bull. 27: 1008-1009. Johnson, D.W. 1944a. Mysterious craters of the Carolina coast; a study in methods of research. Am. Sei. 32: 1-22. Johnson, D.W. 1944b. Mysterious craters of the Carolina coast. Am. J. Sei. 5:247-255. Johnson, R.L. 1978. Timber harvests from wetlands. Pages 598-605 rn_ P-E- Greeson, J.R. Clark, and J.E. Clark, eds. Wetland functions and values: the state of our understanding. Proceedings of the National Symposium on Wetlands, Lake Buena Vista, n a. American Water Resources Association. Johnson, R.R., and J.F. McCormick (techn ical coordinators). 1979. Strategies for protection and management of floodplain wetlands and other ripar ian ecosystems. For. Ser. Gen. Tech. Rep. WV-12, USDA, Washington, D.C. Jones, R.A., and T.M. Sholar. 1981. The effects of freshwater discharge on estuarine - nursery areas of Pamlico Sound. Rep. CHIP 79-11, N. C. Dep. Nat. Resources Comrn. Dev., Div. of Marine Fisheries, Morehead City, N.C. Jones, R. H. 1981. A classification of lowland forests in the northern coastal plain of South Carolina. M.S. Thesis. Clemson University, Clemson, S.C. 177 pp. Jones, V.L. 1956. Discussion of "Were the Carolina bays oriented by gyro scopic action?" by W. Schriever. Trans. Am. Geophys. Union 37:116-117. Kaczorowski, R.T. 1976. Origin of the Carolina bays. Pages II.16-II.36 jn_ M.O. Hayes, et al. 1976. Terrigenous clastic depositional _environments._ |Un;wersity of South Carolina. Coastal Res. Div., Tech. Rep. No. 11. Kaczorowski, R.T. 1977. The Carolina bays: a comparison with modern oriented lakes. Ph.D. Thesis. Uni versity of South Carolina, Columbia. Kaufman, C.M., J.B. White, and R.J. Monroe. 1954. Growth of pond pine in a pocosin area. J. For. 52:275- 279. Kearney, T.H. 1901. Report on a botani cal survey of the Dismal Swamp re gion. Contrib. U.S. Nat. Herb. 5:321-550. Kelley, W.R., and W.T. Batson. 1955. An ecological study of the land plants and cold-blooded vertebrates of the Savannah River project area. Part VI. Conspicuous vegetational zona- tion in a "Carolina bay." Univ. S.C. Publ. Ser. Ill Biol. 1:244-248. Kelly, A.O., and F. Dachille. 1953. Tar get: Earth—the role of large meteors in earth science. Target:Earth. Publ., Carlsbad, Calif. 263 pp. / Kerr, W.C. 1875. Physical geography, resume, ecological geology, vol. 1. Geological Survey of North Carolina, Raleigh. 120 pp. Kirby-Smith, W.W., and R.T. Barber. 1979. The water quality ramifications 1n estuaries of converting forest to intensive agriculture. (Rep. No. 148), WRRI, North Carolina State University, Raleigh. Kologiski, R.L. 1977. The phytosociology of the Green Swamp, North Carolina. North Carolina Ag. Exp. Stn., Tech. Bull. 250. 101 pp. Komarek, E.V., Sr. 1965. Fire-ecology- grasslands and man. Proc. 4th Annual Tall Timbers Fire Ecology Conference 169-220., Tallahassee, Fla. Justis, L. 1974. Swamps that puzzle everybody. The Atlanta J. Constitu tion Mag. Nov. 10, 1974:10-21. Kormondy, E.J. cellulose 1968. 'Weight loss of and aquatic macrophytes 84 in a Carolina bay. Limnol. Oceanogr. 13:522-526. Kuchler, A.W. 1964. Potential natural vegetation of the conterminous United States. American Geographical Soci ety, Spec. Publ. No. 36. Kuenzler, E.J., and H.L. Marshall. 1973. Effects of mosquito control ditching on estuarine ecosystems. (Rep. No. 81), WRRI, North Carolina State University, Raleigh. Kuenzler, E.J., P.I. Mulholland, L.A. Ruley, and R.P. Sniffen. 1977. Water quality in North Carolina coastal plain streams and effects of channel ization. Rep. No. 127. WRRI, North Carolina State University, Raleigh. Laessle, A.M. 1942. The plant communi ties of the Welaka area. University Fla. Press Biol. Sei. Ser. 4:1-143. Laessle, A.M. 1968. Successional and environmental relationships of the forest vegetatton of north central Florida. Am. Midi. Nat. 79:441-457. Lee, D.S. 1982. A preliminary survey of the mammals of the First Colony Farm lands in Dare County, North Carolina. U.S. Fish and Wildlife Service, Divi sion of Ecological Services, Raleigh, N.C. Lee, D.S., C.R. Gilbert, C.H. Hocutt, R.E. Jenkins, D.E. McAllister, and J.R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum. 854pp. Lee, W.D. 1955. The soils of North Caro lina, their formation, identification and use. N. C. Agric. Exp. Stn. Tech. Bull. No. 115. i LeGrand, H.E. 1953. Streamlining of the Carolina bays. J. Geol. 61:263-274. Lilly, J.P. 1981a. The blackland soils of North Carolina, their characteristics and management for agriculture. N.C. Agric. Res. Ser. Tech. Bull. 270. Lilly, J.P. 1981b. A history of swamp land development in North Carolina. Pages 20-39 Jji C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. t Lindenmuth, W.D., and J.M. Vasievich. 1981. An economic analysis of inten sive timber management in pocosins. Pages 270-282 j[n C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Lohman, S.W. 1972. Ground-water hydrau lics. U.S. Geolog. Surv. Prof. Pap. 708. 70 pp. Louder, D.E. 1962. An annotated check list of the North Carolina bay lake fishes. J. Elisha Mitchell Sei. Soc. 78:68-73. Loveless, A.R. 1961. A nutritional inter pretation of sclerophylly based on differences in the chemical composi tion of sclerophyllous and mesophytic leaves. Annu. Bot., n. s. London, 26:168-184. Loveless, A.R. 1962. Further evidence to support a nutritional interpretation of sclerophylly. Annu. Bot., n. s. London, 26: 551-561. MacCarthy, G.R. 1936. Magnetic anomalies and geologic structures of the Caro lina coastal plain. J. Geol. 44:396- 406. MacCarthy, G.R. 1937. The Carolina bays. Bull. Geol. Soc. Am. 48:1211-1226. MacCarthy, G.R., W.F. Prouty, and J.A. Alexander. 1933. Some magnetometer observations in the coastal plain area of S. C. Elisha Mitchell Sei. Soc. J. 49:20-21. Maki, T.E. 1974. Factors affecting forest production on organic soils. In Histosols: their characteristics, use and classification. Soil Sei. Soc. Am., Madison, Wis. Maki, T.E., W. Hazel, and A.J. Weber. 1975. Effects of stream channel ization on bottomland and swamp forest ecosystems. North Carolina State University, School of Forest Resources, Raleigh. 41 pp. 86 Maki, T.E., A.J. Weber, D.W. Hazel, S.C. Hunter, B.T. Hyberg, D.M. Fllnchum, O.P. Loll is, J.B. Roynstad, and J.D. Gregory. 1980. Effects of stream channelization on bottomland and swamp forest ecosystems. Rep. No. 147. WRRI, North Carolina State University, Raleigh. Martof, B.S., W.M. Palmer, J.R. Bailey, and J.R. Harri son, III. 1980. Amphibians and reptiles of the Carolinas and Virginia. University of North Carolina Press, Chapel Hill. 264 pp. McCampbell, J.C. 1943. Further geo magnetic evidences as to the origin of the "Carolina bays." Ph.D. Thesis. University of North Caro lina, Chapel Hill. McCampbell, J.C. 1944. An evaluation of the artesian hypothesis of origin of the Carolina bays. J. Elisha Mitchell Sei. Soc. 60: 183-185. McCampbell, J.C. 1945a. A geomagnetic survey of some Bladen County, North Carolina, "Carolina bays." J. Geol. 53:66-67. McCampbell, J.C. 1945b. Meteorites and the 'Carolina bays." Pop. Astron. 53:388-392. McDaniel, S. 1971. The genus Sarracenia (Sarraceniaceae). Bull. Tall Timbers Res. Stn. 9:1-36. McDonald, C.B., and A.N. Ash. 1981a. A natural area inventory of Tyrrell Co., N.C. Coastal Energy Impact Program Report No. 7. Office of Coastal Management, Department of Natural Resources and Community Development, Raleigh, N.C. McDonald, C.B., and A.N. Ash. 1981b. A "^survey of natural areas in Tyrrell County, North Carolina. Final report of research, North Carolina Natural Heritage Program, Department of Natural Resources and Community Development, Raleigh. Mclver, H. 1981. Green Swamp Nature Preserve, Brunswick County, North Carolina. North Carolina Nature Con servancy, Chapel Hill. McMillan, M.A., and R.D. Semlitsch. 1980. Prey of the dwarf salamander, Eurycea quadri'di'gitata, in South Carolina. J. Herpetol. 14:424-426. Melton, F.A. 1933. The Carolina "bays"... - are they meteorite scars? Tulsa Geol. Soc. Digest (1933):12. Melton, F.A. 1934a. The origin of the Car olina "bays." Discovery 15:151-154. Melton, F.A. 1934b. Reply to "The origin of the supposed meteor scars," by C. W. Cooke. J. Geol. 42:97-104. Melton, F.A. 1937. Geological theories on origin of the Carolina "bays." Geol./Soc. Am. Bull. 49:312. JT Melton, F.A. 1938. Possible late Creta ceous origin of the Carolina "bays." Geol. Soc. Am. Bull. 49:1954. Melton, F.A. 1950. The Carolina "bays." J. Geol. 58:128-134. Melton, F.A., and W. Schriever. 1933a. The Carolina "bays"...are they mete orite scars? J. Geol. 41:52-66. Melton, F.A., and W. Schriever. 1933b. The Carolina "bays'...are they mete orite scars? Sei. Am. 149:106-107, 158-159, 188-189. Merriam, C.H. 1895. Revision of the am, ir.n. XU3-J. ,>v_..-._.. shrews of the American genera Blarina and Notiosorex. North American Fauna No. 10. U.S. Department of Agricul ture, U.S. Government Printing Office. Washington, D.C. Milliman, J.D., and K.O. Emery. 1968. Sea levels during the past 35,000 years. Science 162:1121-1123. Monk, C.D. 1966. An ecological signifi cance of evergreenness. Ecology 47:504-505. Monk, C.D. 1971. Leaf decomposition and loss of 45Ca from deciduous and ever green trees. Am. Midi. Nat. 86:379- 384. 86 Monschein, T.D. 1981. Values of pocosins to game and fish species in North Carolina. Pages 155-170 jn C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Strouds- burg, Pa. Mulholland, P.J. 1979. Organic carbon cycling in a swamp stream ecosystem and export by streams in eastern North Carolina. Ph.D. Dissertation. University of North Carolina, Chapel Hill. 151 pp. Nature Conservancy. 1981. Southern bot tomlands. Nat. Conserv. News 31(2). Newton, R.B., and J.A. Jusler. 1978. Wet land protection: a selected biblio graphy. University of Massachusetts Institute for Man and Environment, Washington, D.C. 79 pp. North Carolina Department of Natural and Economic Resources. 1977. Soil associations of the coastal area man agement region. Raleigh, N.C. North Carolina Department of Natural Re sources and Community Development. 1978. North Carolina's 1978 state wide comprehensive outdoor recreation plan. Raleigh, N.C. North Carolina Department of Natural Re sources and Community Development. 1979. Trends in North Carolina's commercial fisheries (1965-1975). Raleigh, N.C. North Carolina Department of Natural Re sources and Economic Resources. 1979. North Carolina game lands maps for hunting and fishing (1979-1980). Raleigh, N.C. North Carolina Land Policy Council. 1974. Criteria for the identification of areas of environmental concern pre pared for North Carolina Land Policy council. North Carolina Land Policy Council, Raleigh. 129 pp. North Carolina Office of Coastal Zone Man agement Fisheries Assistance Program. 1979. A plan for management of North Carolina's estuarine fisheries—phase I. Raleigh, N.C. North Carolina Water Resources Research Institute. 1980. North Carolina's five-year water research program for 1982-1987. North Carolina Water Re source Research Institute, Raleigh, N.C. 80 pp. North Carolina Wildlife Resources Commis sion. 1980. Application for federal assistance: wildlife management in North Carolina, October 1, 1980 - September 30, 1985. Department of Natural Resources and Community Development, Raleigh, N.C. Oaks, R.Q., Jr., and N.K. Coch. 1973. Post-Miocene stratigraphy and mor phology, southeastern Virginia. Va. Div. Mineral Resour. Bull. 82. 135 PP. Odum, H.T. 1952. The Carolina bays and a Pleistocene weather map. Am. J. Sei. 250:263-270. Costing, H.J. 1956. The study of plant communities. W.H. Freeman and Co., San Francisco, Calif. 440 pp. Otte, L.J. 1981. Origin, development and maintenance of pocosin wetlands of North Carolina. Unpublished Report to the North Carolina Natural Heri tage Program. North Carolina Depart ment of Natural Resources and Commun ity Development, Raleigh. 51 pp. Otte, L.J., and R.L. Ingram. 1980. 1980 annual report on peat resources of North Carolina. Rep. No. DE-AC01- 79ET-14693. North Carolina Energy Institute, U.S. Department of Energy. Oxford English Dictionary (OED). 1971. Vol. II, compact edition. Oxford University Press, Oxford, England, p. 1038. Parmenter, R.R. 1980. Effects of food availability and water temperature on the feeding ecology of pond sliders (Chrysemys s. scripta). Copeia 1980 (Chrysemys ^ (3):503-514. Pate, P.P., and R. Jones. 1980. Effects of upland drainage on estuarine nursery areas of Pamlico Sound, North Carolina. Rep. P & SI-50. North 87 Carolina Department of Natural Re sources and Community Development, Office of Coastal Manage., Morehead City, N.C. Patterson, K.K. 1978. Life history aspects of paedogenic populations of the mole salamander, Ambystoma talpoideum. Copeia 1978:649-655. Penfound, W.T. 1952. Southern swamps and marshes. Bot. Rev. 18: 413-446. Peterson, C.H., and N.M. Peterson. 1979. The ecology of intertidal flats of North Carolina: a community profile. U.S. Fish and Wildlife Service, Of fice of Biological Services, Washing ton, D.C. FWS/OBS-79/30. 73 pp. Pettry, D.E., J.H. Scott, Jr., and D.J. Bliley. 1979. Distribution and nature of Carolina bays on the east ern shore of Virginia. Va. J. Sei. 30:3-9. Plummer, G.L. 1963. Soils of the pitcher plant habitats in the Georgia coastal plain. Ecology 44:727-734. Pocosin..."swamp on a hill." n.d. Na tional Forests in North Carolina. (Pamphlet available from District Ranger, U. S. Forest Service, 435 Thurman Rd., New Bern, N. C. 28560.) Porcher, R.D., Jr. 1966. A floristic study of the vascular plants in nine selected Carolina Bays in Berk eley County, S.C. Master's Thesis. University of South Carolina, Colum bia. Poste!, S.L. 1981. The economic benefits of pocosin preservation. Pages 283- 302 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Potter, ^E. 1982. A preliminary assess ment" of the wintering bird fauna of the First Colony Farm lands in Dare County, North Carolina. U. S. Fish and Wildlife Service, Division of Ecological Services, Raleigh, N.C. Preston, C.D., and C.Q. Brown. 1964. Geologic section along a Carolina bay, Sumter County, South Carolina. Southeast. Geol. 6:21-29. Prouty, W.F. 1934. Carolina bays. J. Elisha Mitchell Sei. Soc. 50:59-60. Prouty, W.F. 1935. elliptical lake 43:200-207. "Carolina bays" and basins. J. Geol. Prouty, W.F. 1936. Further evidence in regard to the origin of Carolina bays and elliptical lake basins. Geol. Soc. Am. Pr. 1935:96-97. Prouty, W.F. 1938. Carolina bays. Trans. Am. Geophys. Union, Geomagnetic In vest., Univ. of N. C., pi. 5, p. 217. Prouty, W.F. 1943. The Carolina bays. The Compass, Sigma Gamma Epsilon 23:236-244. x Prouty, W.F. 1948. Reply to "Observa tions on the Carolina 'craters' or 'bays,'" by B. Barringer. Pop. Astron. 56:499-501. Prouty, W.F. 1950. Origin of the Caro lina bays. Pop. Astron. 58:17-21. Prouty, W.F. 1952. Carolina bays 'and their origin. Bull. Geol. Soc. Am. 63:167-224. Putnam, J.A., G.M. Furnival, and U.S. McKnight. 1960. Management and inventory of southern hardwoods. U.S. Department of Agriculture Hand book 181. 102 pp. \ Radford, A.E. 1950. Notes on Isoetes in North Carolina. J. Elisha Mitchell Sei. Soc. 66:84-86. / Radford, A.E. 1977. Natural area classi fication systems: a standardized scheme. In A. Marmel stein, ed. Pro ceedings of the Symposium on Classi fication, Inventory and Analysis of Fish and Wildlife Habitat. U. S. Fish and Wildlife Service, Office of Biological Services, Washington, D.C. Radford, A.E., H.E. Ahles, and C.R. BelV. 1968/ Manual 'of the vascular flora of the Carolinas. University of North Carolina Press, Chapel Hill. 88 Radford, A.E., D.K.S. Otte, L.J. Otte, J.R. Massey, and P.D. Whitson. 1980. Natural heritage: classification in ventory and information. University of North Carolina Press, Chapel Hill. Research Triangle Institute. 1982. Pru- lean Farms environmental assessment. Prepared by Prulean Farms Joint Venture. Richardson, C.J., ed. 1981a. Pocosin wetlands. Hutchinson Ross Publishing Co., Stroudsburg, Pa. 364 pp. Richardson, C.J. 1981b. Pocosins: eco system processes and the influence of man on system response. Pages 135- 151 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Richardson, C.J. 1982. Pocosins: vanish ing wastelands or valuable wetlands? BioScience (submitted). Richardson, C.J., R. Evans, and D. Carr. 1981. Pocosins: an ecosystem in transition. % Pages 3-Ï9 in C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Strouds burg, Pa. Richardson, C.J., R.K. Evans, and D. Carr. 1982. Status of pocosin wetlands (freshwater evergreen shrub bogs) in coastal North Carolina as of 1980. Map. Integrated Case Studies Program in Natural Resources Analysis, School of Forestry and Environmental Stud ies, Duke University, Durham, N.C. Roberts, P.R., and H.L. Oosting. 1958. Responses of the Venus fly trap (Dionaea muscipula) to factors involved in its endemism. Ecol. Monogr. 28:193-218. i Robertson, E.G. 1962. The Carolina bays and emergence of the coastal plain of the Carolinas and Georgia. USGS Prof. Pap. 450-C (C90), U. S. Geolog ical Survey, Washington, D. C. Robinson, I.R., Jr. 1977. Bobwhite quail foods in pocosin habitat planted to pine. M.S. Thesis. North Carolina State University, Raleigh, N.C. Robinson, I.R., Jr., and F.S. Barkalow, Jr. 1979. Bobwhite quail foods in pocosin habitat converted to pine. J. Wildl. Manage. 43(2):516-521. Roe, C.E. 1981. The preservation of pocosins: an overview. Pages 189-195 jji C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Rose, R.K. 1981. Small mammals in openings in Virginia's Dismal Swamp. Brimleyana 6:45-50. Sass, H.R. 1944. When the comet struck (Carolina bays). Sat. Evening Post 217:12-13, 105, 107. Schalles, J.F. 1979. Comparative lim nology and ecosystem analysis of Carolina bay ponds on the upper coastal plain of South Carolina. Ph.D. Thesis. Emory University, Atlanta, Ga. Schimper, A.F.S. 1898. Pflanzengeo- graphies auf physiologischen Grund lage. Fischer, Jena. Schlaudt, E.A. 1955. Drainage in forestry management in the South. Water, Yearbook of Agriculture. U.S. Dep. Agric., Yearb. Agric.:564-568. Schlesinger, W.H., and B.F. Chabot. 1977. The use of water and minerals by evergreen and deciduous shrubs in Okefenokee Swamp. Bot. Gaz. 138: 490-497. Schriever, W. 1951. On the origin of Carolina bays. Trans. Am. Geophys. Union 32:87-95. Schriever, W. 1956. Discussion of "Were the Carolina bays oriented by gyro scopic action?' by W. Schriever. Trans. Am. Geophys. Union 37:117. Schwartz, F., and A.F. Chestnut. 1973. Hydrographie atlas of North Carolina estuarine and sound waters. 1972. University of North Carolina, Sea Grant Program, Chapel Hill. Semlitsch, R.D. 1980. Growth and meta morphosis of larval dwarf salamanders 89 (Eurycea quadridigitata). Herpeto- logia 36:138-140. Semlitsch, R.D. 1981a. Effects of implanted tantalum-182 wire tags on the mole salamander, Ambystoma talpoideum. Copeia 1981(3): 735-737. Semlitsch, R.D. 1981b. Terrestrial activity and summer home range of the mole salamander (Ambystoma talpo i - deum). Can. J. Zool.59:315-322. Semlitsch, R.D., and M.A. McMillian. 1980. Breeding migrations, popula tion size structure, and reproduction of the dwarf salamander, Eurycea quadridigitata, in South Carolina. Brimleyana 3:97-105. Semlitsch, R.D., K.L. Brown, and J.P. Caldwell. 1981. Habitat utilization, seasonal activity, and population size structure of the southeastern crowned snake (Tantilla coronata). Herpetologica 37:40-46. Shard, S.J. 1946. Dust devils? Paral lelism between the S. African salt pans and the Carolina bays. Sei. Monthly 62:95. - Sharitz, R.R., and J.W. Gibbons. 1982. Carolina bays: unique natural wet lands of the southeastern coastal plain. (In prep.) Shaw, S.P., and C.G. Fredine. 1956. Wet lands of the United States. U.S. Fish and Wildlife Service, Washington, D.C. Shew, R.D. 1979. Geology of the area between Fayetteville and Elizabeth- town, North Carolina. M. S. Thesis. University of North Carolina, Chapel Hill. 114 pp. Shields, J.D., N.D. Woody, A.S. Dicks, G.J. Hollod, J. Schalles, and G.J. Leversee. 1980. Locations and areas of ponds and Carolina bays at the Savannah River Plant. E. I. Dupont de Nemours & Co., DP-1525, Aiken, S.C. 19 pp. Shockley, N.G., C.R. Kolb, and W.B. Steinriede. 1956. Discussion of "Were the Carolina bays oriented by gyroscopic action?" by W. Schriever. Trans. Am. Geophys. Union 37:112-115. Sinnott, A. 1953. Carolina bays of the Coastal Plain of Virginia. Va. J. Sei. 4:258. (Abstr.) Skaggs, R.W, J.W. Gilliam, T.J. Sheets, and O.S. Barnes. 1980. Effect of agricultural land development on drainage waters in the North Carolina tidewater region. Rep. 159. Water Resources Research Institute of the University of North Carolina, Raleigh. 2974 pp. Smith, L.L. 1931. Solution depressions in sandy sediments of the coastal plain in South Carolina. J. Geol. 39:641-652. Snyder, J.R. 1977. Report on the vegeta tion and site factors of the pond- pine pocosin research natural area, Croatan National Forest. USDA South east. Exp. For. Stn., Asheville, N.C. Snyder, J.R. 1978. Analysis of the vege tation in the Croatan National For est, North Carolina, M.S. Thesis. University of North Carolina, Chapel Hill. Sossaman, E.C., Jr. 1973. Seasonal food habitats of white-tailed deer (Odo- coileus virginianus) in a treated North Carolina pocosin. M.S. Thesis. North Carolina State University, Raleigh. Street, M.W., and J.D./ McClees. 1981. North Carolina's coastal fishing industry and the influence of coastal alterations. Pages 238-251 im C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Strouds- burg, Pa. Taggart, J.B. 1981. Pocosin natural areas in North Carolina. Pages 171-182 in C.J. Richardson, ed - Pocosin wéï^" lands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Tardell, J.B., R.C. Yates, and D.H. Schil ler. 1981. New records and habitat observations of Hyla andersoni Baird 90 (Anura: Hylidae) from Chesterfield and Marlboro Counties, Sou,th Caro lina. Brimleyana 6:153-158. Taylor, M. 1978. Clean sweep in the coastal plain. Wildl. N.C. 42(8): 7-13. Taylor, M. 1981. Hot issue down east. N.C. Wildl. 45(8):10-15. Teate, J.L. 1967. Some effects of envi ronmental modifications on vegetation and tree growth in a North Carolina pocosin. Ph.D. Dissertation. North Carolina State University, Raleigh. Terrell, T.T. 1979. Physical regionali- zation of coastal ecosystems of the United States and its territories. U.S. Fish and Wildlife Service, Coastal Ecosystems Project. (FWS/OBS- 78/80). Teulings, R.P., and J.E. Cooper. 1977. Cluster areas. Pages 409-415 in J.E. Cooper, S.S. Robinson and J.B. Funderburg, eds. Endangered and threatened plants and animals of North Carolina. North Carolina State Museum of Natural History, Raleigh. Thorn, B.G. 1970. Carolina bays in Horry and Marion Counties, South Carolina. Bull. Geol. Soc. Am. 81:783-813. Tilly, L.J. 1973. Comparative productiv ity of four Carolina lakes. Am. Midi. Nat. 90:356-365. Tooker, W.W. 1899. The adapted Algonquin term "Poquosin." Am. Anthropol., Jan.:162-170. Tourney, M. 1848. Report on the geology of South Carolina. Geol. Surv. S.C. 143-144. U.S. Army Corps of Engineers. 1980. Scoping report: Prulean Farms land conversion, Dare Co., North Carolina. U.S. Army Corp of Engineers, Wilming- ton Dist., Wilmington, N.C. U.S. Army Corps of Engineers, Wilmington District. 1981. Scoping report: Prulean Farms, Dare County, North Carolina. Wilmington, N.C. U.S. Department of the Interior, National Park Service. 1979. Study of alternatives: Green Swamp, North Carolina. 113 pp. U.S. Fish and Wildlife Service. 1979. Coastal ecosystem characterization— summary of activities FY 1975 through FY 1979. National Coastal Ecosystems Team, Washington, D.C. (FWS/OBS- 79/01). U.S. Fish and Wildlife Service. 1980. Survey scope report. Attachment t£ Norfolk Harbor and channels, Vir ginia, deepening and disposal feasi bility report. Appendices. Depart ment of the Army, Corps of Engineers, Norfolk District, Norfolk, Va. Wahlenberg, W.G. 1960. Loblolly pine, its use ecology, regeneration, protection, growth and management. Seeman Printery, Inc., Durham, N.C. Watts, W.A. 1979. Late Quaternary vege tation history of White Pond on the inner coastal plain of South Caro lina. Quat. Res. 13:187-199. Wells, B.W. 1928. Plant communities of the coastal plain of North Carolina and their successional relations. Ecology 9:230-242. Wells, B.W. 1932. The natural gardens of North Carolina. University of North Carolina Press, Chapel Hill. Wells, B.W. 1942. Ecological problems of the Southeastern United States coastal plain. Bot. Rev. 8:533-561. Wells, B.W. 1946. Vegetation of Holly Shelter Wildlife Management Area. N.C. Dep. Cons. Develop. Bull. 2. 40 pp. Wells, B.W., and S.G. Boyce. 1953a. The Bladen Lakes: advancing or retreat ing bog margins. J. Tenn. Acad. Sei. 28:190. Wells, B.W., and S.G. Boyce. 1953b. Carolina bays: additional data on their origin, age and history. J. Elisha Mitchell Sei. Soc. 69: 119-141. 91 Wells, B.W., and S.G. Boyce. 1954. Caro lina bay lakes: the bog margin prob lem. Ecology 35:584. Wells, B.W. and I.V. Shunk. 1928. A southern upland grass sedge bog: an ecological study. N.C. Agric. Exp. Stn. Tech. Bull. 32. Wells, B.W., and I.V. Shunk. 1931. The vegetation and habitat factors of the coarser sands of the North Carolina coastal plain: an ecological study. Ecol. Monogr. 1:466-520. Wells, B.W., and L.A. Whitford. 1976. History of stream head swamp forests, pocosins and savannas in the South east. J. Elisha Mitchell Sei. Soc. 92:148-150. Wendel, G.W., T.G. Storey, and G.M. Byram. 1962. Forest fuels on organic and associated soils in the coastal plain of North Carolina. USDA For. Serv., Southeast. Exp. Stn. Pap. 144, Ashe- ville, N.C. Wharton, C.H. 1970. The southern river swamp—a multiple use environment. Bureau of Business and Economic Research, School of Business Adminis tration, Georgia State University, Atlanta. 48 pp. Wharton, C.H. 1978. The natural environ ments of Georgia. Geologic and Water Resources Division and Resource Planning Section, Office of Planning and Research, Georgia Department of Natural Resources, Atlanta, Ga. ' 227 pp. Wharton, C.H., W.M. Kitchens, E.C. Pendle- ton, and T.W. Sipe. 1982. The ecology of bottomland hardwood swamps of the Southeast: a community profile. U.S. Fish and Wildlife Service, Biological Services Pro gram Washington, D.C. FWS/OBS- 81/37. Whigham, D.F. 1981. An outside perspec tive on the pocosin conference and suggestions for future work. Pages 345-356 iji C.J. Richardson, ed. Pocosin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Whitehead, D.R. 1963. "Northern" elements in the Pleistocene flora of the Southeast. Ecology 44:403-406. Whitehead, D.R. 1964. Fossil pine pollen and full-glacial vegetation in south eastern North Carolina. Ecology 45: 767-777. Whitehead, D.R. 1972. Developmental and environmental history of the Dismal Swamp. Ecol. Monogr. 42: 301-315. Whitehead, D.R. 1973. Late-Wisconsin vegetational changes in unglaciated Eastern North America. Cuat. Res. 3:621-631. Whitehead, D.R. 1981. Late-Pleistocene vegetational changes in northeastern North Carolina. Ecol. Monogr. 51: 451-471. ' Whitehead, D.R., and K.W. Tan. 1969. Modern vegetation and pollen rain in Bladen County, North Carolina. Ecology 50:235-248. Wilbur, H.M. 1981. Pocosin fauna. Pages 62-68 in C.J. Richardson, ed. Poco sin wetlands. Hutchinson Ross Publ. Co., Stroudsburg, Pa. Wilder, H.B., T.M. Robinson, and K.L. Lindskov. 1978. Water resources of northeast North Carolina. Water Res. Invest. 77-81. U.S. Geol. Surv., Raleigh, N.C. Williams, T.M. 1978a. \ An approach to measuring runoff ' from forested coastal watersheds. IMPAC Reports 3(4). U pp. Williams, T.M. 1978b. Response of shal low water tables to rainfall. Pages 363-370 in W.E. Balmer,- ed. Proceed ings: Soil Moisture Site Productiv ity Symposium. USDA Forest Service Southeastern Area State and Private Forestry. / Williams, T.M. 1979. Implications of hydrologie response to the practice of forestry on coastal forests. Pages 93-102 jji W.H. x'Smith, ed. Proceedings: forest practice and 92 water. 1979 Annual Meeting Fla. Sect. Soc. Am. For. Wilson, E.J. 1978. A floristic study of the "Savannahs" on pine plantations in the Croatan National Forest. Master's Thesis. University of North Carolina, Chapel Hill. Wilson, K.A. 1962. North Carolina wet lands, their distribution and manage ment. Federal Aid in Wildlife Resto ration Project W-6-R. North Carolina Wild Resources Commission, Raleigh. 169 pp. Winner, M.D., Jr., and C.E. Simmons. 1977. Hydrology of the Creeping Swamp watershed, North Carolina, with reference to potential effects of stream channelization. U.S. Geol. Surv. Water Res. Invest. -77-26. 54 pp. Woodwell, G.M. 1956. Phytosociology of coastal plain wetlands in the Carolinas. M.S. Thesis. Duke Uni versity, Durham, N.C. 50 pp. Woodwell, G.M. 1958. Factors controlling growth of pond pine seedlings in organic soils of the Carolinas. Ecol. Monogr. 28:219-236. Wylie, C.C. 1933a. Iron meteorites and the Carolina "bays." Pop. Astron. 41:410-412. Wylie, C.C. 1933b. Meteoric craters, meteors, and bullets. Pop. Astron. 42:469-471. Yarbro, L.A. 1979. Phosphorus cycling in the Creeping Swamp Watershed. Ph.D. Dissertation. University of North Carolina, Chapel Hill. 243 pp. 93 a02n -i pi__________ REPOR DOCUMENTATION PAGE l._ REPORT NO. FrJS/QBS-82/Q4 4. Title and Subtitle THE ECOLOGY OF SOUTHEASTERN SHRUB BOGS (POCOSINS) AND CAROLINA BAYS: A COMMUNITY PROFILE 7. Author« Rebecca R. Sharitz and J. Mhitfield Gibbons 9. Authors' Affiliation Savannah River Ecology Laboratory Ai ken, SC 29801 12. Sponsoring Organization N«me and Address U.S. Fish and Wildlife Service Division of Biological Services Department of the Interior Uashinaton. DC 20240______ 3. Recipient's Accession No. 5. Report Date November 1982 8. Performing Organization Rept. No. /Task/Work Unit No. 11. Contract(C) or Grant(G) No. (C) (G) 13. Type of Report & Period Covered 14. J2L 15. Supplementary Notes 1 1C. Abstract (Limit: 2OO words) / Shrub bogs of the Southeast occur 1n areas of poorly developed internal drainage that'typi cally but not always have highly developed organic or peat soils. Pocosins and Carolina bays are types or subclasses of shrub, bogs on the coastal plains of the Carolinas and Georgia. They share roughly the same distribution patterns, soil types, floral and faunal species composition and other community attributes, but differ in geological formation. Carolina bays may contain pocosin as well as other communities, but are defined more by their unique elliptical shape and geoirorphometry. The pocosin community is largely defined by its vegetation, a combination of a dense shrub understory and a sparser canopy. The community is part of a complex successional sequence of communities (sedge bogs, savannas, cedar bogs, and bay forests) that may be controlled by such factors as fire, hydroperiod, soil type, and peat depth. , Pocosins and Carolina bays harbor a number of animal groups and may be locally important in their ecology. Although few species are endemic to these habitats, they may provide important refuges for a number of species. These communities are simultaneously among the least understood and most rapidly disap pearing habitats of the Southeast.——Fnrpst.ry anH agn'riilt.ural rlparagp are rurrpnt impacts] 17. Document Analysis a. Descriptors ' ^ Ecology, ecological succession, peat deposits, perched water, animal ecology, plant ecologj b. Identlflers/Opan-Ended Terms Shrub bogs, pocosins, Carolina bays, fire ecology, palustrine wetlands / c. COSATI Field/Group 18. Availability Statement Unlimited 19. Security Clan CThlc Report) Unclassified 2O. Security Clan (This Pace) 21. No. of Pag« X + 93 22. Price (S« ANSI-239.18) OPTIONAL FORM 272 (4-77) (Formerly NTIS-35) Department of Commerce LEGEND Headquarters - Division of Biological Services, Washington, D.C. National Coastal Ecosystems Team, Slidell. La. Regional Offices U.S. FISH AND WILDLIFE SERVICE REGIONAL OFFICES REGION 1 Regional Director U.S. Fish and Wildlife Service Lloyd Five Hundred Building, Suite 1692 500 N.E. Multnomah Street Portland, Oregon 97232 REGION 2 Regional Director U.S. Fish and Wildlife Service P.O.Box 1306 Albuquerque, New Mexico 87103 I REGION 3 Regional Director U.S. Fish and WUdlife Service Federal Building, Fort Snelling Twin Cities, Minnesota 55111 REGION 4 Regional Director U.S. Fish and Wildlife Service Richard B. Russell Building 75 Spring Street, S.W. Atlanta, Georgia 30303 REGION 5 Regional Director U.S. Fish and Wildlife Service One Gateway Center Newton Corner, Massachusetts 02158 REGION 6 Regional Director U.S. Fish and Wildlife Service P.O. 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