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Ecology of Wetlands and Associated Sysum.r. Edited by S.K. Majumdar, E.W. Miller and Fred J. Brenner C 1998, The Pennsylvania Academy of Sc:ienc:e. Chapter Twenty-Three

WETLAND HABITATS FOR WILDLIFE OF THE CHESAPEAKE BAY MATTHEW C. PERRY Patuxenc Wildlife Research Center Laurel, MD 20708

. : . INTRODUCTION .

Early explorers co the Chesapeake Bay were amazed With the seemingly inexhaustible wildlife resources associated with the ~e tl ands of the Bay (1). Although explorers su~h as John Smith were the first to report in writing of these resources. it was some of ¢e traders who.were most descriptive because of their . intense interest and close involvement ih the commercial value of .wildlife. An understanding of the population size of some of the wildlife that thrived in the Bay when the country was first settled can be obtained from .the reports and journals of some of the early explorers and traders. · · One such person was Captain Henry Acct, who was more. of a materialist than explorer and left the Jamestown Colony in 1632 "for the rich country to the north .. (I). In June he travelled to Anacostia (now Washington. D.C. area) along the Pocomac River where he obtained "800 weight of beaver'' (Castor canadensis) (2). In the summer of 1632 he trave ll~d north again to Patobanos (Port Tobacco) where he found 5000 Indians willing to kill beaver and preserve their furs·: He estimated that they would obtain 5-6 thousand pounds of furs- before his ne;"(t trip. in the spring (3). Fleet's ability to deal with the Indians was probably enhanced because he had been a prisoner of theirs in earlier years and was proficient in their language (I). Wetland Habitats for Wildlife of the Chesapeake Bay 333

The wild animals seen by the early explorers of Chesapeake Bay were numerous because of the expansive and fertile wetlands that characterized the Bay. Few areas in the world have supported such tremendous populations of wildlife, and these populations, although now much reduced in numbers, are still one of the reasons the Bay has attracted such attention from nature lovers, scientists, and the public. One· of the factors causing the decline of wildlife populations is the continued loss of natural wetlands (estuarine and palustrine) in the Bay and throughout its watershed. Based on aerial surveys, the greatest losses occurred among the forested wetlands (4). The only wetlands in the Bay watershed that have increased in acreage were human created ponds and these may have limited value to wildlife. The classification of wetlands has received considerable atcencion from many agencies responsible for the regulations established to proted them (5, 6). In this chapter wetlands are broadly grouped into three major categories (shallow-water wetlands, emergent wetlands, and forested wetlands) based mainly on the type of vegetation that dominates the area. This general categorization of wetland tJPes has been selected because of the mobility of wildlife (especially birds), which allows them to traverse several habitats in a s~ort period of time. · In this discussion, shallow-water wetlands ·are those that are mainly open water areas near shore usually with some trpe of submerged aquatic vegetation . (SAY). These wetlands also include mud flats and sand bars often in close association with open water areas. Emergent wetlands are usually found adjacent to shallow-water wetlands and have primarily herbaceous emergenc planes as the dominant vegetation. Forested wetlands are dominated by trees and shrubs, and often are adjacent to emergent wetlands. In this discussion, only minor consider­ ation is given to specific modifiers of wetlands (water regime, water chemistry, and soil) as described by Tiner and Burke (6). ' This chapter reviews wildlife that use these three generai wetland habitats. Wildlife discussed in this chapter are the species that are most obvious or unique (Table I), and no attempt is made to deal with all specieS .or groups of speCies. Wildlife is grouped into four major categories: birds, mammals, reptiles, ·and amphib­ ians. Invertebrates and fish are not·considered in this chapter, although it is ·recog­ nized that they form important components in the stri.icture.of wetland ecosystems . .. !

BIRDS

Among the vari9us groups of birds in the Bay area; .waterfowl (swans, geese. and ducks) are probably the most obvious. Swan:; in the Bay· include the tundra swan (Olor columbianus) and the mute sw;in (Cygnus olor), while the geese include the Canada goose (Branra canadensis) and two s~bspecies of the Sf)OW goose (Chen ·caerufescens): :The ducks are comprised of 21 species and are divided inco cwo major types (dabbling and diving) bused on their feeding behavior. Diving ducks completely submerge ~hile feeding, where::is. dabbling ducks jus1 tip-up or dabble in shallow water. · · · 334 Ecology of Wetlands and Associated Systems

TABLE l Wildlife Sptcies that art Rtprtstntative of tht lVetla11ds of Chtsaptakt Bay BIRDS Sl1allow-wat1r wetlands: Canv:uback Aythya valisineria Redhead Aythya americana Bald eagle Haliattrus ltucocephalu.s Osprey Pandion haliattus Great blue heron Ardta htrodias Killdeer Charadrius vociftrus Emtrgtnt wetlands: American Black duck Anas rubripts M:i.llard Anas platyrhynchos Northern hnnier ·Circus c:yantus Sora Pof7.arta carolina Red-winged blackbird Agelaiu.s photnictus Marsh wren Cistothorus palustris Forested wetlands: Wood duck Aixsponsa Red-shouldered hawk Butto lintatus Bam:d owl Strix van'a Common yellowthroat Gtochlypis trichas

MAMMALS Shallow-water wetlands: No mammal consered endemic to this habitat in the Bay. Emtrgtnt wttl.ands: Muskrat Ondatra r.ibtrhic11s Nutria Myocastor coypus Meadow vole Micorus ptnsylanicus Fornttd wetl.ands:· Beaver · ; · Castor canadtnsis River otter · Lulra canadtnsis . White-footed mouse Peromyscus leucopu.s . ' Delmarva fox squirrel Sciurus niger cinertus

REPTILES AND AMPHIBIANS Shailow-wattr wetlands: Diarnondback terr.tpin Malaclemys terrapin Snapping turtle Clielydra strptntina Emtrgtnt wit/ands: Northern wnter snake , . Ntrodia sipedon Painted turtle C~rysemys picta Foresttd wetlands: Wood frog Rana sylvatica Spring peeper Pstudoacris cnicifer M:itbled salamander Ambystoma opac11111 Spotted salamander Amb.vstoma 111ac11lcu11m Wetland Habitats for Wildlife of the Chesapeak4 Bay • 335

Waterfowl that winter on Chesapeake Bay now number less than one million individuals (7), although they once probably ranged from 10-15 million. When waterfowl surveys began in the late 1940s following World War II, there were counts of over 200-400 thousand for several duck species such as the canvasback (Aythya valisineria), greater scaup (A. marila), lesser scaup (A. affinis), and American black duck (Anas rubripes) (8). It is possible that before the commer­ cial ("market") hunting of waterfowl in the late 1800s (9), that they may have numbered 10 times what they did when surveys began in the late 1940s. Unfortunately, the only record we have of the numbers is the eye-witness accounts of the hunters and naturalists and the reportS of the thousands of birds that went to the markets for over two decades (9). One eye-witness account described the water as black with ducks, that the sound when they took flight was like the rumbling of distanc thunder, and that over one square mile of the sky was covered with ducks at one time ( l ). Raptors (or birds of prey) as a group include the eagles, hawks, and owls and typically feed on animal food, which they obtain by hunting. Because they typi­ cally are high flying birds that may soar for long periods they can be associated with many habitat types. Some arc resident to the Bay while others just migrate through the Bay area. One biologis·t in 1949 recorded 2214 hawks on migration over a pond near Solomons, Maryland, during a seven-hour period (10). Wading birds (herons and egrets) as a group arc medium- to large-sized birds. Like the raptors, they feed high on the food chain and, therefore, have received attention as species affected by chemical contaminants. Because they nest in large groups they often are referred to as colonial nesting birds (11). Shore birds are represented by the sandpipers and plovers, that feed mainly on invertebrates and seeds in sand or mud substrates. Rails are more secretive than shore birds and usually associated with heavy vegetative cover. Both groups were heavily hunted around the turn· of the century and their numbers were greatly reduced during this penod. Most species are now totally; pro­ tected by the 1918 Migratory Bird Treaty Act. The Act allows hunting regula: tions to be promulgated each year for some· shorebirds, such as American woodcock (Scolopax minor), common snipe (Gallinago gallinago), and for some rail species.

Shallow-water Wetlands

The shallow-water wetlands of the Bay proper historically have been important wintering areas for waterfowl ( 12). Some species, such as the tundra swan and the Canada goose, intensively used the.shallow-water wetlands where they fed on SAY (13, 14). During the period between l952 and .1956, the average wintering population of- cundro swans in the Bay constituted nearly half of the continental population and about three-fourths of_the Atlantic coastal population ( 1S) . Populations of Canada geese .were always high in the Bay, bu.t :i.ctually increased when SAY declined. because it contributed to the conversion to :i. com 336 Ecology of Wetlands and Associated-Systems

diet that was more beneficial during the winter. With the high energy com diet, geese required less feeding time and therefore less exposure to hunting. Now swans and geese are more frequently observed in agricultural fields where they feed on waste com left from commercial harvest operations or on field cover crops (7, 16). Goose populations reached a high count of over 700,000 in 1981 before declining probably due to overharvest. especially from guided hunting parties, that changed their hunting techniques to take advantage of field feeding by the geese. The canvasback has always been the most abundant duck species in the Bay and, although their present numbers are reduced (7), they still remain the most numerous of all duck species using the Bay. Among duck 'hunters and nature lovers they still rank as the duck that is "King of the Bay" ( 17). The canvasback played an imponant role in the ·interesting, but sometimes tragic, market hunting era when this duck was an epicurean delight (9). Historically, canvasbacks fed on submerged aquatic vegetation such as wild celery (Vallisneria americana) (18), but because beds of SAY declined they now feed predominately on mollusks. especially the Baltic clam (Macoma balthica) (19). Although SAV now forms a small portion of the diet of canvasbacks, there still are many species of freshwater wetland planes that are still included in the diet of canvasbacks. These planes are found in the uibutaries of the Bay and emphasize the importance of these wetland areas to this speCies. Haramis provides more detail on the life history, habitat requirements, and special prob­ lems of canvasbacks (20) and one of their close relatives the redhead (Aythya americana) (21). The redhead still feeds predominantly on SAY and did not make the change in oiet as the ca!lvasbacks did (22). As a result, redhead populations have declined in abundance as SAY has declined in acreage (7). Among the captors t~e bald eagle (Haliaeetus le11cocephal11s) nod the osprey (Pandion haliaetus) are most characteristic users of shallow-water ·wetlands. The bald eagle once occurred commonly throughout the Bay (23). Abundnnt food in the shallow-water wetlands enabled eagles to produce large broods with four-egg nests being commo.n. Discussions on the life history, habitat requirements, a~d special , ·problems have been·presented for the ·bald eagle (23) and osprey (24, 2.5, 26). After World War II the use of pesticides such as DDT increased dramati­ cally in the Bay area: Chemicals were applied extensively over wetlands, especially coastal ~arshes, to help control insect pests, predominantly mos­ quitoes. After the contamination and degradation of the environment with DDT, the raptor food buse was still available, buc now concained persistent pesticides, that when metabolized within the birds, adversely affecte.d their ability co deposit calcium in the eggshell. The result was eggshells that were thinnerchan normal, thus reduced produccivicy (21. 28). In the 1980s. four-egg . clutches were again found in eagle nests in the Bay. This wa:; a result of the ban on DDT in 1972. which was excellent evidence of improved habitat con­ ditions. There now are approximately 250 pairs of eagles and 2000 pairs of ospreys nesting in. the Bay. . -

Wetland Habitats for Wildlife oftht Chtsaptakt Bay 337

Throughout the shallow-water wetlands of the Chesapeake Bay one can frequently observe the great blue heron (Ardea herodias), the largest and most common of the wading birds in the Bay · ( 11 ). The great blue herons of Chesapeake Bay constituted half of the approximately 12,000 colonies from Maine to Georgia in the mid- l 970s. Recent surveys in Maryland and Virginia indicate a population increase for the great blue heron. Populations of the great egret (Casmerodius a/bus), snowy egret (Egretta thula), green heron (Bucorides striatus), and the black-crowned night heron (Nyccicorax nycticorax) are stable in the Bay (11). The little blue heron (Egretta caerulea) is the least common of the ~ix species of colonial wading birds and is the one with an apparent declining population ( 11). These six colonial nesting species and the other wading birds are closely related and can be frequently observed stalking small fish and invertebrates in shallow waters (l l). Many shorebirds, including the sandpipers and plovers, are migratory and can be seen foraging in the spring and fall on the shores in shallow-water wetlands of the Bay. Greater yellowlegs (Tringa melanoleuca) and lesser yellowlegs (Tringaflavipes) are commonly seen shorebirds and usually can be identified by their distinctive caJI notes. The killdeer (Charadrius vociferus) is probably the best known shorebird and is found throughout the Bay watershed. It feeds along the shores of the Bay, near ponds, and in fields. It often nests on human created habitats, such as gravel driveways and parking lots.

~mergent Wetlands

Dabbling ducks typically use emerge~t .:Vetlands ~o~ 'ilian diving ducks. A~~ng the dabbling ducks, the American black• duck ruiS• 'alwaysr ~en the most numerous on the Bay (7). Black ducks occur in both tidal and n9n-tidal wetlands where they feed on a variety of invertebrates and plant species. Stewan (13) sho~ed the importance·,. . of SAY in the diet of black ducks, but in more recent years: as SAY declined, these ;.. · ducks have ben more closely associated with emergent wetland plant habitats. Black duck populations have declined in rece~t y~ and some biologi.S~ tiave suggested· ,. competition from the mallard (Anas platyrhynchosY as one of the causes (29. 30, 31).. ... , Mallards, which arc propagated and released in large numbers in the :say, use the same emergent wetland habitat as' the black duck and hav,e similar food habits. · The black duck has traditionally nested in the Bay _area using ·both emergent · and woody habitat for nest sites. Stotts (32) found large n~mb.:rs of black ducks nesting on isl:i.nds of the Bay in the 1950s, but when these sites were resurveyed · in the 1980s m:>.ny of the islands hnd disappenred or were ,greatly 'reduced in size· by erosion (33). For ex:imple, Poplar"Island on the E~Jem Shore 'in 1847 w~ approximately 1000 acres :>.nd now is only ~ acres. A major projc!<:t by the Corps : of Engineers will restore wetlands and upland habitats wich dredge material.: Restoration of Poplar Island and ocher ·say islands should benetii the black duck by providing nesting habitat in areas h:i.vi'ng minimal exposure from predators. · ·· Among the captors, the northern harrier (Circus cyw1eus). is the species most 338 Ecology of Wetlands and Associated Systems

typical of the emergent wetlands of the Chesapeake Bay. It is seen flying slowly at low elevations over the marshes in search of small mammals and other prey. The short-eared owl (Asio flammeus) is another species that is found in emergent wetlands, especially the more open tidal marshes with h.igher salinity (34). Both the northern harrier and the short-cared owl are more common over the Bay wetlands during the winter, but normally breed further north. However, there are nest records for both species in Maryland, moslly in Dorchester County (35). All six of the colonial nesting species utilize the tidal and non-tidal emergent wetlands as well as the shallow-water wetlands. In tidal wetlands they are most successful feeding at low tide on the small fish that are stranded by the receding waters. Analagous situations occur in the non-tidal emergent wetlands during droughts or when water levels are artificially drawn down in human managed impoundmencs. All six species of North American rails can be found in the wetlands of the Chesapeake Bay (36). The king rail (RaliLt.S elegans) and the clapper rail (Rallus longirosrris) are the largest They arc sirnifa.r in appearance and size, but.differ in their habitat preference. The king rail is most often found in fresh water wetlands and the clapper rail in brackish or salt marshes. The Virginia rail (Rallus limicola) is about half the size of the king and clapper rails and occurs in both fresh and brackish water marshes. The sora (Pon.ana carolina), yellow rail (Cotttmicops noveboracensis), and black rail (Lcrtuallus jamaicensis) are the three smallest in descending order. The yellow rail is the least abundant of the Bay rails and occurs in the same habitat as the sora. Although it is protected as a non-hunted species, it is occasionally mistaken as a sora by hunters (37). The black rail is the most secretive of the rails ruid occurs most commonly in the brackish Eastern Shore marshes, especially Elliot Island, Maryland (36, 38). There is only O!lC record of its nesting on the Western Shore of the Bay (35), but nests are very difficult to find even in the Eastern Shore marshes (36). The sora is a rail of the emergent wetlands. Although not immediately seen by the casual observer, the sora can be hea.rd as it commonly responds co a hand clap or other loud sound (39). The sora has re~eived increased attention in recent years because of concern that populations may be declining as a result of degraded migrational habitat (pers. comm., M. Hararnis. G. Keams). ·. The sora has an extremely interesting history as a game bird that has been hunted in the Bay " marsh~s since al least 1802 (40). Soras were pursued in the fall throughout the B:iy by "gentlemen" hunters who hired "pushers" to propel their flat-bottom boat through the marsh (39, 41). In 1881, two hunters killed 1225 sor:is in two days in a marsh along the fames River (42), indicaling the large number of soras that resided in the Bay at thnt time. The wild rice (Zitania aquatica) marsh of the Patuxcnt River is one of the last nreo.s this species still frcqucncs during their fall migration. Their st~p-over occurs shortly :ifter the wild rice and other seeds fall to the w:itcr and these seeds form the bulk of their diet (43). Unfortunately, for m:iny yc-..irs the :icrc:igc of wild rice has been declining while that of common recd (Phragmites a1t.Stralis) has been incre:i.sing (44). This may be due to increased amouncs of nucriencs :ind Wetland Habitats for Wildlife ofthe Chesapeake Bay 339

sediment from expanding human populations in the Patuxent River watershed. Among the smaller birds the red-winged blackbird (Agelaius phoeniceaus) rates as the most conspicuous in the emergent wetlands. It is most apparent in the spring when males, with bright red "epaulets" on their wings, defend their tenitories Red-wing populations have increased probably more than any other bird in North America because of their ability to adjust to human agricultural activities (45). The bobolink (Dolichonyx oryzivorns) was once very common in the wild rice marshes in many areas of the Bay, including the marshes of the Anacostia River near Washington, D.C. (46). Most of these marshes are gone because they were filled with dredge spoil. The bobolink was heavily hunted for sport and market, and was considered a delicacy (36, 39). Today sightings of the bobolink are uncommon and bring great excitement from birding· enthusiasts. The bobolink migrates through the Bay in the spring and fall, while ·travelling between breeding areas in Canada and wintering areas in Brazil. One of the most common nesting songbirds in the emergent wetlands of the Bay is the marsh wren (Cistothorus palustris). It can be found nesting in both broad-leaved cattail (Typha latifolia) in the fresh water weclands as well as the narrow-leaved cattail (Typha angustifolia) of the brackish water wetlands (36, 38). The swamp sparrow (Meiospiw georgiana) is a common winter resid~nc in the. emergent wetlands of the Bay, but a srriall population also nests in the. Nanticoke River marshes (38). Recent nests· have been discovered ac Black Marsh· near Baltimore and sparingly elsewhere on the western shore of the Bay (47).

Forested Wetlands · . ' ' ' · ...··: . The wood duck (Aix sonsa), as its name indicates, i~ a species of the forested wetla.nds where it breeds, feeds, and rests. Hollow ·tr~es along the rivers and streams are used for nesting, but shortly after'hatchin,fthe female takes her brood to emergent habitat where invertebrates can be found co s~pply the.protein neeciS' of the growing young. H!lfamis (48) provide5 a complete review of. the ~natural history, habitat requi~ements, and special problems for this.species in' the.Bay. ' The red-shouldered hawk (But_eo ;lineatus) is a species of the forested.wetlands, where it feeds on amphibians, 'reptiles, .~d rodents. inhabiting the forest' floor. Long-term research along large sections of the Patuxent ~ver (49) have indi!=ated that the population has been affected by increasing development, which reduced the amount of forested wetlands available to this s~cies (pers. comm., E. Manin). Barred owls (Strix varia) also occur in the forested wetland habitat and have food habits similar to the red-shouldered hawks. Because they are· nocturnal, the owls feed at different time periods than the hawks and there appear to be little conflict. Numerous songbird species utilize forested wetlands and most have restrictive ranges based on the Stage of ecological succession of the forest. The common yellowthroat ( Geotlilypis trichas) is asun-loving sped es found in the cra~sitional shrub swamp. Stewart found I 08 pairs of yellowthroats per I 00 acres in this habitat at Pacuxent Research Refoge in 1948 (50). Other common species of . ' . 340 Ecology of Wetlands and Associated Systems

forested wetlands in the Bay area are the American redstart (Serophaga ruticilla) and the wood thrush (Hylocichla musre/ina). ·

MAMMALS

Although the birds of the Chesapeake Bay received more attention by early explorers and traders, and even by present-day naturalists and scientists, the mammals were an abundant and important resource of the Bay wetlands. At least one mammal species, the beaver, was a major reason that many upper areas of the tributaries of Chesapeake Bay were explored by early explorers and traders (l, 2, 3). The beaver, however, was not recorded from the Washington. D.C. area in 1896 and 1923 when Bailey reported mammal species within 20 miles of the Capital (5 l, 52). Beavers were probably extirpated from the wetlands of the Chesapeake Bay area around 1800 and then returned around 1939 (53) as a result of protection and restocking programs. · Some species of mammals. such as the raccoon (Procyon lotor), are found throughout the Chesapeake Bay watershed and in all known habitats. except open water. The raccoon is a predator on many species of birds although there is little documentation of their effect in the Bay area. One study along Rock Creek (a tributary of the.Potomac River) showed low incidence of racoon predation on vertebrates, although low incidence by high raccoon populations was considered a potential problem for some prey species (Unpub. Report, D. Manski and J. Hadidian 1985). In wetlands of the north-central part of North America the raccoon is considered a major predator on waterfowl, especially the canvasback, that migrates to Chesapeal

Shallow-water Wetlands

No one species of mammal can be considered as endemic to shallow-water wetlands. Many species like the raccoon and red fox (Vulpes falva) use the edges of these habitats at night while in search of food, then recrent to more vegetnted habitats during the day. The red fox was imported from Englnnd into Maryland 1650 (53) for use in fox hunting, which was popular with the early immigr:i.nts. It is not known if the present red fox populations in Maryland are descendnnts of foxes from England or from the native red fox that might have come into the area from the "north as the land was cleared by settlers. Muskrat (Ondarra ziberhicus), benver, and river otter (Lutra canademis) :ilso use the shallow-water wetlnnds while in tr:i.nsit co ocher hnbitats, but :ire more typic:il of emergent or forested wednnds. The open water of the Bay mny be frequented by severnl species of large mnrine m:imm:ils chnt form nn interesting role in these ecosystems. Becnuse of their r::iricy. however. they h:ive not been well documented or studied. The species Wetland Habitats for Wildlife of the Chesapeake Bay 341

that could most likely be expected in shallow-water wetlands of the Chesapeake Bay are the bottle-nosed dolphin (Tursiops truncatus) and the harbor seal (Phoca vitulina). The bottle-nosed dolphin has been reported as far up the tributaries of the Bay as Washington, D.C. and Havre de Grace, Maryland (53). The harbor seal has been reported as far north in the Bay as Elkton, Maryland (53) and also in the mouth of the James River, Virginia (54). In recent years, the warm water loving manatee (Trichechus manams) has been seen in the Bay and has caused much interest among the public. These sightings are unusual and probably have not been made in the past, based on the absence of records (53, 54). The first manatee seen in 1994 was considered "confused" and was captured, fitted with a radio transmitter. and returned co Aorida. It was named "Chessie" after the mythical Bay "creature" and received much media attention. In 1995. Chessie reappeared in the Bay (and later was sighted as far north as Rhode Island) indicating it might not have been as confused as some of the biologis'ts trying to capture it. It is not known whether the manatee was feeding on SAV while in the Bay or if it could maintain itself this far north during the warmer months of the year.

Emergent Wetlands

The mammal which is indisputably the most obvious and probably most ecologically significant in the emergent wetland is the muskrat. This rodent occurs throughout the Bay in tidal and non-tidal emergent wetlands: it feeds almost entirely on vegetation. especially three square. (Scirpus olneyi and S. americana) and cattail, which have high amounts of energy-producing search in their tubers. This vegetation is also used to build their characteristic mound houses that are visible from a distance. . . . .' • Muskrat populations have traditionally ·been h!ghest in · th~ marshes of . Dorchester County, Maryland, especially during the 1920-30s (55. 56). Extensive studies of muskrats were conducted at Blackwater National Wildlife Refuge by Herbert L. Dozier in the late-1930s and 1940s (57), some of which was conducted to support of the War.effort for the production of food and fur. Muskrat seem to be good pioneers into new habitats that have abundant vegecacion, but they probably become the main control of their own numbers by reducing the available food supply. Other factors that control population include drought. floods. and cold weather (56). Trapping has been a successful manage­ ment technique to maintain populations at opcimum levels and avoid excessive "eatouts" (57). Limited eatout by muskrats do provide excellent habitat for rails (38). Another rodent that has habits similar to the muskmt is the exotic nutria (M_vocastor coypus). This species was introduced into the wild in Maryland in the early 1940s as a potencial fur-producing animal (53). Unfonunmc:ly, shortly nfrer introduction fur prices fell. and. with less population control from trapping. the species range expanded. In the Bay area the: nutria is mllst common in the 342 Ecology of Wetlands and Associated Systcrru

Blackwater National Wildlife Refuge where they are blamed for the decreasing amount of emergent wetlands. Other factors that are implicated in the decline of wetlands in this area are land subsidence (due to groundwater extraction) and sea level rise (due to melting of ice caps). The role of the nutria is presently being stud­ ied by federal scientists with the use of exclosures (pers. comm., G.M. Haramis). Among the smaller mammals the meadow vole (Microtus pensylvanic11s) is the most abundant and is found in fresh or brackish emergent marshes. The vole is found in dense vegetation, such as the grass redtop (Agroscis .stolonifera). They construct numerous tunnels in the vegetation and above the ground with active tunnels having conspicuous cuttings (1-21 of green vegetation along the runs. The rice rat (Oryr.omys palustris) is another common rodent of the emergent wetlands, but is more common in the brackish tidal areas. The rice rat will occupy the nests of marsh wrens (38) and might be a problem species without control of their numbers in the absence of natural predators.

Forested Wetlands

Although many mammal species live in forested wetlands, few can be classified as totally dependent on chis habitat. Many mammal species found i!' forested wetlands are also very successful in emergent wetlands. The mammal most commonly associated with forested wetlands, however, is the beaver. Beavers typically live on streams or rivers, and build dams co impound the water, resulting in pond habitats. The flooding allows the beaver to increase its area for foraging and creates wetland habitat for many other species. Another mammal associated with a forested wetland is the white-footed mouse (Peromyscus le~copus), .:-v"hich is seldom fo~nd in emergent wetlands, but is closely .associated with \v~ody vegetation. . The loblolly pine forests of the Eastern Shore are mainly forested wetlands and these· habitats' are important co the Delmarva fo_x squirrel '(Sciurus niger · -· cinereus), which is an endangered species. Studies (perS. comm., .c.r. Bocecti, O.H. Pattee) are currently underway to determine the effect of timber harvest in these forests on the squirrel while evaluating field techniques ~d by Taylor to evaluate squirrel habitat (58). The white-tailed deer (Odocoileus virginiana) is the largest land mammal in the Chesapeake Bay area. It is very common in forested wetlands and often uses the emergent _wetl:mds for feeding. The deer. however, was not mentioned in lists of mammals by Bailey (51, 52), and Paradiso (53) states that deer were nearly exterminated in Maryland (rom 1900 to the early 1930s. Handley lists simil~ dates for Virginia (54). ·

REPTILES AND AMPHIBIANS

Although less conspicuous 1han the birds and mammals in 1he Bay wetlands. Wetland HabitalS for Wildlif~ of the Chmrpt!akL Bay 343

the cold-blooded vertebrates are important componentS of the Chesapeake Bay wetlands. Fifty-five species of reptiles and amphibians have been reported from Maryland and the District of Columbia (59). Thirty-nine of these species have been found at the Jug Bay Wetlands Sanctuary along the Patuitent River (60), although some of these were collected from upland forests. One of the earliest accounts of a large sea turtle in the Bay was in .1755 when one was caught in the Chester River and weighed ninety pounds (1). Other records indicate that the Atlantic loggerhead (Caretta careua) and the Atlantic leatherback (Dermochelys coriacea) have both been recorded in the Bay (61) with the leatherback as recently as 1995 (62).

Shallow-water Wetlands

The terrapin (Malaclemys terrapin) historically has been an important reptile specie~ found in the shallow-water wetlands of the Bay. It is found in both brackish and sail water habitats, and once was a major food source, being used by Chesapeake Bay chefs for their famous turtle soup. Amphibian species usually do not occur in the brackish and salty shallow­ water habitat of the Bay. In the freshwater shallow areas of rivers and creeks one can find species that are often found in the emergent or forested wetlands. The mud eel,. or great siren (Si;en lacerrina), was reported as verging on its nort~em limit (2), and has not been reported in the Bay wetlands since the late 1800s (59). ' , Emergent Wetlands

The terrapin was once abundant in ali salt marshes of Maryland, but by 1940 it was· reported to be greatly reduced in numbers (61 ); a trend that continues today. Shells found along the saltmarsh shorelines· indicate the continued presence of this species, however. Alth~ugh nC? speci~s :of reptile is unique "to emergent wetlands. there are several species that can be routinely seen. The most common is the Northe!11 water snake (Ne.rodia .sipedon), which occurs in a variecy of water habitats. Several turde species frequent emergent wetlands with open water areas. Here they can bask in the sun, but dive co safety in bottom mud if necessary. The painted turtle (Chrysemys picta) is the species mosc commonly seen. : .:, · The snapping turtle (Chelydra serpentina) is common throughout the Chesapeake Bay region in brackish as well as fresh-water emergent wetlands. The snapper has been blamed for being n major predator of·waterfow:I. but numerous studies of food habits indicate that their food is mainly veget:ition, :ilthough as opportunists. they will probably take other food as it ·becomes Qvai\'1ble. There are reports of cygnets. go:.lings, :ind ducklings being dragged under water. The webs of swans and gcc:~c often show the scars (tom webs :ind missing digits) of past encounters with snappers. •

344 Ecology of Wetlands nnd Associnted Systems

Forested Wetlands

The wood frog (Rana sylvatica) is the most common amphibian associated·· with the forested wetlands of the Bay area. Depressional wetlands within the forest are used for breeding by wood frogs in March, sometimes when ice is.still present. These ephemeral wetlands (sometimes called vernal pools) are often dry shortly after the tadpoles metamorphose into frogs. The spring peeper (Pseudoacris crucifer) is also common in forested weclands. It prefers shrubby wet areas along the edges of forests for breeding and its distinctive courtship calls are a precursor of spring. Eighteen species of salamanders occur in the Chesapeake Bay area with many being located in forested wetlands. Their presence is usually not obvious without using trapping techniques or intensive searches. Most species of salamanders travel to still waters for breeding, but spend most of the year in more elevated moist areas that have much decaying organic material. The marbled salamander (Ambysroma opacum) and spotted salamander (A. macularum) are the most com­ mon species of salamanders in the Chesapeake Bay forested wetlands.

CONCLUSIONS

The wetlands of Chesapeake Bay have provided the vi!al habitats that have sustained the impressive wildlife populations that have brought international fame to the Bay. As these wetland habitats decrease in quantity and quality we will continue to see the decline in the wildlife populations that started when European settlers first came to this continent. These declines have accelerated significantly in this century. As the human population continues to increase in the Bay watershed (63), ·one can expect that wetland habitats will continue to decline, resulting in ·declines in species diversity and population numbers. Although federal, state, and locnl governments are striving for "no net loss" of wetlands, the results to date are not encouraging. It is unrealistic to believe that hum:in populations and associated development can continue to increase and not adversely affect the wetland resources of the Bay. Restrictions on human population growth in the Chesapeake area is clearly the best way to protect wetland habitats and the wildlife that are dependent on these habitats. In addition, there should be more aggressive approaches to protect wet­ land habitats from continued perturbations from humans (64, 65). More sanctuary ·areas should be created (66) and there should be gre:iter use of enhancement and management techniques that will benefit the full complement of species that potentially exist in these wetlands (67). The present trend in wetland loss c:in be expected to continue as human populations increase with resultant incre:ises in roads, shopping malls. and housing developments. Cre:ition of habitat for miti­ gation of these losses will not result in "no net loss". More innovative :ipproaches should be employed to reverse the long-term trend in wetland loss by humans . . ..

Wetland Habitats for Wildlife of the Chesapeake Bay 345

ACKNOWLEDGEMENTS

Brooke Meanley and Lynda Garrett provided several references unknown to the author and a review of the manuscript. Other helpful comments on the manuscripts were recevied from Fred Fallon, Richard Hammerschlag, Michael Haramis; Greg Kearns, Daniel McAuley, Peter Osenton, Christopher Swarth, and John Taylor. Their assistance is greatly appreciated.

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