Taxa and Special Effects Summaries S89 critical levels of suspended sediment above primary productivity. Chesapeake Sci. 10:307-312. which the will not exist. I. SCULTHORPE, C. D. 1967. The biology of Ruppia maritima has also been shown to be aquatic vascular . St. Martins Press, N.Y. sensitive to increased water temperatures, 610 p. particularly at the time of new growth from 8. ANDERSON, R. R. 1970. The submerged rhizomes (11). This plant has been observed to vegetation of Chincoteague Bay. In Assateague ecological studies. Univ. Md. Natural Resources decline significantly around the effluent of a Inst. Contr. No. 446. steam electric generating station (12). 9. TRIDENT ENGINEERING ASS. 1968. Chesa- peake Bay case study. Clearinghouse Pub. No. REFERENCES P~l79844. 1. HOTCHKISS, N. 1964. Pondweeds and 10. PHILLIPS, R. C. 1960. The ecology of plants of pondweed-like plants of Eastern North America. Crystal Bay, . Quart. .I. Fla. Acad. Sci. Bur. Sport Fish. Wildl. Cir. 187. 23:328-337. 2. EYLES, DON E. 1944. A guide and key to the 11. SETCHELL, W. A. 1920. Geographical aquatic plants of the Southeastern United States. distribution of the marine spermatophytes. Bur. Sport Fish. Wildl. Cir. 158. TorreyBat. Club Bull. 47~563-579. 3. FASSETT, N. C. 1969. A manual of aquatic 12. ANDERSON, R. R. 1969. Temperature and Dlants. Univ. Wisconsin Press, Madison. 405 P. rooted aquatic plants. Chesapeake Sci. 4. HOTCHKISS, N. 1967.’ Underwater - and 10: 157-164. floating-leaved plants of the United States and Canada. Bur. Sport Fish. Wildl., Resource Publ. 44. 5. ANDERSON, R. R. 1972. Aerial photo RICHARD R. ANDERSON interpretation of the distribution of submerged Department of Biology vascular plants in Chesapeake Bay. In Preparation. The American University 6. ANDERSON, R. R. 1969. The evaluation of species composition as a qualitative factor in Washington, D.C. 20016

Emergent Vascular Plants of Chesapeake Bay Wetlands

Present Status of Taxonomical Knowledge Present Status of Knowledge About the The taxonomic status of both wetland and Distribution and Abundance of the Group upland vascular plants in the northeastern To my knowledge the wetland vegetation of United States has been well defined and worked the Chesapeake Bay has not yet been surveyed over. Contemporary nomenclature and comprehensively enough for construction of organization of the species are presented in two distribution maps of individual species or plant comprehensive identification manuals (1, 2). community types. Ecological studies at scat- Hitchcock (3) gives an excellent coverage of the tered points around the Bay have provided grasses, including a list of their taxonomic some data on relative abundances at the study synonyms. Herbaria which include wetland sites. Most of these studies are cited by Wass & plants of the Chesapeake Bay are available at Wright (5) and by Wass (6). the Smithsonian Institution, the University of Two annotated checklists have recently been Maryland, and the College of William and Mary. compiled for vascular plants of the Chesapeake An ongoing review of the flora of Virginia is Bay and areas potentially subject to flooding by now stimulating additional field collections it (6, 7). The Univ. Md. list of 421 species from Virginia wetlands. Common names have covers all land areas within the high tide limits been coined for most of the vascular plants in of the Bay and its tributaries, both in Maryland the northeastern U.S., but an attempt to and Virginia. The VIMS list of 43.5 species is standardize these names (4) is not yet restricted to Virginia (including the barrier universally accepted. islands of the Atlantic seashore) and the s90 Taxa and Special Effects Summaries

Patuxent River estuary in Maryland. Both lists swamps follow tidal river floodplains on both include the flora of salt and brackish marshes, sides of the Bay. Shreve describes the beaches, and freshwater swamps. The VIMS list composition of hardwood swamp in different also covers ponds and floodplains on tidal locations in considerable detail. Wass & Wright creeks, and shores subject to storm wave (5) briefly describe the vegetation of hardwood inundation. Each list contains many species not swamps in Virginia. found in the other, so together they probably comprise a fairly complete flora of Chesapeake Present Status of Knowledge Concerning the Bay wetlands. However, more field work will be Biology of the Group needed to assure a comprehensive flora. For Little direct research into the morphology example, an intensive floristic survey at Rhode and/or physiology of wetland plants in the River in Anne Arundel County, Maryland (8) Chesapeake has come to the writer’s attention. turned up seven species not included in the Esau (10) described the anatomical adaptations Univ. Md. list and three not included in the of several species, some of which occur in the VIMS list. Bay, to a halophytic environment. Shreve (9) Both lists are annotated to show the noted the adaptations present in Spartina collection sites of species. The annotations in al terniflora. the VIMS list are more detailed and for some Several ecological studies have been made to species indicate relative abundances. However, explain the distribution of species these annotations are insufficient to show and vegetation types in relation to salinity, distribution patterns of the species. Wass & frequency of tidal inundation, substrate Wright (5) found a dearth of floristic data on preference, and other factors. The relative Virginia wetlands and inadequate herbaria in importance of these factors is still disputed. counties bordering the Bay. Current revision of Adams (12) concluded that tide-elevation the Flora of Virginia should improve this factors predominate in determining the situation. distribution of salt marsh species, and Descriptions of the species composition and developed a formula for determining the mean general distribution of the major types of elevation of occurrence for a species at any wetlands (salt and brackish marshes, beaches, location from the range of tide. Adams also and freshwater swamps) are given by Shreve et measured salinities and ion concentrations in al. (9) for Maryland by G. A. Marsh (11) the coastal marshes of North Carolina, where he for Virginia. Table 1 compares the principal found no major differences in salinity among types of salt and brackish marsh vegetation in the plant communities. However, his salinity the two states. As salinity decreases the flora data are probably inapplicable to marshes in the becomes more diverse and finally includes more Chesapeake Bay, where the water is much less species than Table 1 can accommodate. representative of the open sea and is strongly Both Shreve (9) and G. A. Marsh (11) influenced by outflow from the Susquehanna discuss beach vegetation types along the River (Blair Kinsman, pers. comm.). Atlantic seacoast, but only Shreve describes it Only two recent ecological studies have been within the Bay. He notes three zones of made of salt marshes in the Chesapeake Bay. increasing diversity of species as the beach Anderson et al. (13) correlated the distribution becomes higher and less subject to inundation. of 97 species with decreasing salinity along a Limited areas of beach vegetation at Rhode 25mile stretch of the Patuxent River in River in Maryland are described by Higman (8). Maryland. In the more saline marshes, he also Freshwater swamps, which cover large areas noted a zonation of species with increasing along the floodplains of tidal rivers in Virginia elevation. The second study, by Philipp & Brown and southern Maryland, are considered by G. A. (14) correlated 52 species with frequency of Marsh (11) to be the least known of wetland submergence and character of substrate at two types. Shreve (9) describes two principal types sites which differed in salinity at South River, of swamp-cypress and mixed hardwood. In also in Maryland. The results of these two Maryland, cypress swamps occur along the studies are difficult to compare directly, since Pocomoke River in Worcester County and at Anderson worked up the gradation of species Battle Creek in Calvert County. Hardwood occurrence over a large area while Philipp & Taxa and Special Effects Summaries s91

TABLE 1. Salt marsh plant communities described in Maryland and Virginia

Maryland Communities Virginia Communities Habitat (from Shreve, 9) (from Marsh, 11)

HIGH SALINITY

Intertidal zone Spartina alterniflora dominant, Same (lower) often pure

Intertidal zone Spartina alterniflora still Spartina alternifloria dominant, (higher) dominant, associated on the decreases in height as elevation Eastern Shore with Salicornia rises and substrate becomes herbacea, Spergularia marina, sandier. Associated species not A triplex pa&la, & Aster listed. tenuifolius; on the Western Shore with Acnida cannnbina, Limonium carolinianurn, Pluchea camphorata, & Solidago sempervirens

Above mean high Spartina patens & Distichlis Spartina patens & Distichlis tide (flooded by spicata dominate; common spicata dominate lower elevations; spring tide) associates are Aster tenuifolius, Juncus roemerianus may form nearly Aster subulatus, Juncusgerardi, pure stands at higher elevations. Gerardia maritima, Pluchea Common associates are camphorata, & Pluchea foetida Salicornia sp., Borrichia frutescens, stellaris, & Limonium nashii

Flooded only by Not distinguished Spartina patens, scattered Iva storm tide frutescens & Baccharis halimifolia

BRACKISH

Intertidal zone Iva frutescens, Typha angusti- Spartina alterniflora dominant folia, Spartina cynosuroides, (moderate salinity) or Typha or Scirpus olneyi dominant; angustifolia & Peltandra associates include Scirpus virginica (low salinity); robustus, Scirpus americanus, various assoc. Zizania aquatica Above mean high Vegetation similar to high Vegetation similar to high tide salinity marsh, plus varied salinity marsh, plus new associates: Hibiscus palus- species: Fimbristylis sp., tris, Eryngium virginianurn, Pluchea purpurascens, A triplex Phragmites communis, etc. pat&a, Aster tenuifolius (Juncus gerardi & Pluchea (Phragmites rare) foetida are absent)

Flooded only by Baccharis halim[folia, Panicum Vegetation similar to high storm tide virgatum, Cuscuta sp., Stropho- salinity marsh, plus Eupatorium styles umbellata, most species serotinum, Cassia fasciculata, of high salinity marsh Lespedeza capitata

Brown concentrated on the specific particularly that of salt marshes, to the environments of species in only two areas. More Chesapeake Bay ecosystem is well recognized. research will be needed to determine the most Wass & Wright (5) discussed the productivity of important correlations between physical Virginia salt marshes and their ecological environment and species distribution. relationships to the Bay. These relationships include the transfer of nutrients from estuarine Present Status of Knowledge Concerning the water to plants, the trapping of sediment in the Role of the Group in the Bay Ecosystem marsh, the role of plant detritus as a base The importance of wetland vegetation, material for estuarine food chains, the role of s92 Taxa and Special Effects Summaries living marsh vegetation as a source of food and Present Status of Knowledge Concerning the shelter for wildlife, and the stabilization of Sensitivity of the Group to Man-Induced erosion and deposition by marshes. Wass & Environmental Changes Wright also discussed the details of estuarine food webs which begin in the marshes. Apart from deliberate destructive activities A multi-disciplinary research program on such as dredging and filling, wetlands are estuarine and salt marsh ecology is now in sensitive to several forms of pollution and other progress at Rhode River, in Maryland. This human disturbances. Since the distribution of program is conducted by the Smithsonian many salt marsh species evidently depends to Institution and others, and includes studies on some degree upon salinity, engineering projects marsh productivity, detritus food chains, marsh which alter the salinity of portions of the Bay vegetation types, sediment movements, and should likewise alter the floristic composition movements of phosphorus and other nutrients of salt marshes in the affected areas. An in marshes. increased sediment load in tidal creeks from The importance of salt marsh plants to upstream erosion, and thus a heavier deposition wildlife, particularly birds and muskrats, is of sediment in marshes, should gradually induce discussed in detail by Martin et aL(15). Wass & an expansion of the marshes and a change in Wright (5) note examples of wildlife utilization their micro-topography. This appears to be of marsh plants on the Eastern Shore of occurring at the mouth of a tributary of Rhode Virginia. Meanley & Webb (16) have studied the River, but no quantitative data have been taken nesting ecology of the red-winged blackbird in and the biological significance is still salt marshes of the upper Chesapeake. Table 2 speculative. ---a,,, summarizes the examples of salt marsh Teal (17) describes the vulnerability of salt utilization described in these studies. marshes to pollution by heavy metal ions and

TABLE 2. Utilization of salt marsh plants by wildlife

Utilization

Plant Species Food Shelter

Spartina alterniflora eaten by ducks & shore Dense stands shelter many Spartina cynosuroides birds (Spartina seeds important birds; stems are used for Scirpus spp. only to black duck). Rootstocks muskrat houses. Cyperus spp. eaten by geese & muskrat.

Typha angustifolia Tubers important to geese & Nest cover for blackbirds muskrats. Not used by ducks. & marsh wrens.

Distichlis spicata Seeds & rootstocks eaten by Nest cover for ducks, esp. Elocharis spp. ducks. shoveller & cinnamon teal.

Salicornia europaea Branches eaten by geese, seeds by ducks.

Acnida cannabina Seeds eaten by ducks. Roots of Hibiscus used moderately by Hibiscus palustris Juncus eaten sparingly by red-winged blackbirds as nest site. Juncus spp. muskrats.

Iva frutescens Favorite nest cover of red-winged Baccharis halimifolia blackbird, also boat-tailed grackles.

Panicum virgatum Moderate use by red-winged blackbird. Taxa and Special Effects Summaries s93 DDT residues, which accumulate in marshes 7. KRAUSS, R. W., R. G. BROWN, R. D. with sediments and are ingested by marsh RAPPLEYE, A. B. OWENS, C. SHEARER, E. HSIAO, and J. L. REVEAL. 1971. Checklist of invertebrates. He mentions a study of the plant species of the Chesapeake Bay occurring effects of DDT in Long Island salt marshes, but within the hightide limits of the Bay and its gives no citation. Wass &Wright (5) cite a study tributaries. Univ. Md., Botany Dep. Tech. Bull. of the role of Spartina alterniflora in carrying 2002. 8. HIGMAN, D. 1968. An ecologically annotated iron, zinc, and manganese into estuarine food checklist of the vascular flora of the Chesapeake chains. Bay Center for Field Biology, with keys. Pollution by sewage, whether primarily or Smithsonian Inst., Washington, D.C. 232 p. (not secondarily treated, raises the level of nutrients yet formally published). in salt marshes. Wass & Wright (5) noted that 9. SHREVE, F., M. A. CHRYSLER, F. H. BLODGETT and F. W. BESLEY. 1910. The plant Spartina spp. grows taller and has a darker life of Maryland. Maryland Weather Service. Vol. green color than normal when sewage is 3. Johns Hopkins Press, Baltimore. 533 p. present. During the growing season, salt 10. ESAU, K. 1960. Anatomy of plants. John marshes are able to absorb some of the excess Wiley & Sons . 376 p. 11 MARSH, G. A. 1969. In Coastal Wetlands of nutrients which otherwise would create algal Virginia: Interim Report of the Governor and blooms in the estuaries. The role of the marshes General Assembly. Va. Inst. Mar. Sci. Spec. Rep. as a sediment trap is being studied in the Appl. Mar. Sci. 10:56-61. Patuxent. 12. ADAMS, D. A. 1963. Factors influencing vascular Anderson (18) noted the effects of thermal plant zonation in North Carolina salt marshes. Ecology 44(3):445-456. pollution on two salt marsh grasses, Spartina 13. ANDERSON. R. R., R. G. BROWN, and R. D. alterniflora and Phragmites communis. Both RAPPLEYE. 1968. Water quality and plant species could tolerate temperatures up to 35°C. distribution along the upper Patuxent River, Spartina grew about twice as tall in the heated Maryland. Chesapeake Sci. g(3): 145-156. 14. PHILIPP. C. C. and R. G. BROWN. 1965. water. The balance of Anderson’s study was Ecological studies of transition-zone vascular devoted to submersed aquatic plants. plants in South River, Maryland. Chesapeake Sci 6(2):73-81. REFERENCES 15. MARTIN, A. C. H. S. ZIM, and A. L. NELSON. 1. FERNALD, M. L. 1950. Gray’s manual of 1951. American wildlife and plants, a guide to botany. 8th ed. American Book Co., N. Y. 1632 wildlife food habits. Dover Publ., N. Y. 500 p. P. 16. MEANLEY, B. and J. S. WEBB. 1963. Nesting 2. GLEASON, H. A. 1968. The new B&ton and ecology and reproductive rate of the red-winged Brown illustrated flora of the northeastern United blackbird in tidal marshes of the upper States and adjacent Canada. Hafner Publ., N. Y. 3 Chesapeake Bay region. Chesapeake Sci. vols. 4(2):90-100. 3. HITCHCOCK, A. S. 1951. Manual of the grasses 17. TEAL, J. and M. TEAL. 1969. Life and death of of the United States, 2nd ed. U.S. Dep. Agric. the salt marsh. Little, Brown & Co., Boston, 278 Misc. Publ. 200. 105 1 p. P. 4. KELSEY, H. P. and W. A. DAYTON. 1942. 18. ANDERSON, R. R. 1969. Temperature and Standardized plant names. 2nd ed. McFarland rotted aquatic plants. Chesapeake Sci. Co., Harrisburg. 673 p. 10(3-4): 157-164. 5. WASS, M. L. and T. D. WRIGHT. 1969. Coastal wetlands of Virginia: interim report of the DANIEL HIGMAN Governor and General Assembly. Va. Inst. Mar. Sci. Spec. Rep. Appl. Mar. Sci. 10. 154 p. Chesapeake Bay Center for 6. WASS, MARVIN L. (Ed.). August, 1972. A Environmental Studies Check-list of the Biota of Lower Chesapeake Bay with Inclusions from the Upper Bay and the Smithsonian Institution Virginia Sea. VIMS Spec. Sci. Rep. No. 65. Edgewater, Maryland 21037