Effect of climate fluctuations on long-term vegetation dynamics in Carolina bay wetlands
Tóm tắt
Carolina bays and similar depression wetlands of the U.S. Southeastern Coastal Plain have hydrologic regimes that are driven primarily by rainfall. Therefore, climate fluctuations such as drought cycles have the potential to shape long-term vegetation dynamics. Models suggest two potential long-term responses to hydrologic fluctuations, either cyclic change maintaining open emergent vegetation, or directional succession toward forest vegetation. In seven Carolina bay wetlands on the Savannah River Site, South Carolina, we assessed hydrologic variation and vegetation response over a 15-year period spanning two drought and reinundation cycles. Changes in pond stage (water depth) were monitored bi-weekly to monthly each year from 1989–2003. Vegetation composition was sampled in three years (1989, 1993, and 2003) and analyzed in relation to changes in hydrologic conditions. Multi-year droughts occurred prior to the 1989 and 2003 sampling years, whereas 1993 coincided with a wet period. Wetland plant species generally maintained dominance after both wet and dry conditions, but the abundances of different plant growth forms and species indicator categories shifted over the 15-year period. Decreased hydroperiods and water depths during droughts led to increased cover of grass, upland, and woody species, particularly at the shallower wetland margins. Conversely, reinundation and longer hydroperiods resulted in expansion of aquatic and emergent species and reduced the cover of flood-intolerant woody and upland species. These semi-permanent Upper Coastal Plain bays generally exhibited cyclic vegetation dynamics in response to climate fluctuation, with wet periods favoring dominance by herbaceous species. Large basin morphology and deep ponding, paired with surrounding upland forest dominated by flood-intolerant pines, were features contributing to persistence of herbaceous vegetation. Drought cycles may promote directional succession to forest in bays that are smaller, shallower, or colonized by flood-tolerant hardwoods.
Tài liệu tham khảo
Brooks, R. T. 2004. Weather-related effects on woodland vernal pool hydrology and hydroperiod. Wetlands 24: 104–14.
Brooks, R. T. and M. Hyashi. 2002. Depth-area-volume and hydroperiod relationships of ephemeral (vernal) forest pools in southern New England. Wetlands 22: 247–55.
Casey, W. P. and K. C. Ewel. 2006. Patterns of succession in forested depressional wetlands in North Florida, USA. Wetlands 26: 147–60.
Chmielewski, R. M. 1996. Hydrologic analysis of Carolina bay wetlands at the Savannah River Site, South Carolina. M.S. Thesis. University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
Collins, B. S. and L. L. Battaglia. 2001. Hydrology effects on propagule bank expression and vegetation in six Carolina bays. Community Ecology 2: 21–33.
Cronk, J. K. and M. S. Fennessy. 2001. Wetland Plants: Biology and Ecology. Lewis Publishers, Boca Raton, FL, USA.
De Steven, D. and M. M. Toner. 2004. Vegetation of Upper Coastal Plain depression wetlands: environmental templates and wetland dynamics within a landscape framework. Wetlands 24: 23–42.
Golladay, S. W., S. Entrekin, and B. W. Taylor. 1999. Forested limesink wetlands of southwest Georgia: invertebrate habitat and hydrologic variation. p. 197–216. In D. P. Batzer, R. P. Rader, and S. A. Wissinger (eds.) Invertebrates in Freshwater Wetlands of North America: Ecology and Management. John Wiley & Sons, Inc, New York, NY, USA.
Haukos, D. A. and L. M. Smith. 1994. Composition of seed banks along an elevational gradient in playa wetlands. Wetlands 14: 301–27.
Hillestad, H. O. and S. H. Bennett, Jr. 1982. Set-aside areas, National Environmental Research Park, Savannah River Plant. U.S. Department of Energy, Savannah River Ecology Laboratory, Aiken, SC, USA. SRO-819-11.
Hook, D. D. 1984. Waterlogging tolerance of lowland tree species of the South. Southern Journal of Applied Forestry 8: 136–49.
Johnson, W. C., S. E. Boettcher, K. A. Poiani, and G. R. Guntenspergen. 2004. Influence of weather extremes on the water levels of glaciated prairie wetlands. Wetlands 24: 385–98.
Johnson, W. C., B. V. Millett, T. Gilmanov, R. A. Voldseth, G. R. Guntenspergen, and D. E. Naugle. 2005. Vulnerability of northern prairie wetlands to climate change. BioScience 55: 863–72.
Jones, R. H. and R. R. Sharitz. 1998. Survival and growth of woody plant seedlings in the understory of floodplain forests in South Carolina. Journal of Ecology 86: 574–87.
Jones, S. M., D. H. Van Lear, and S. K. Cox. 1984. A vegetationlandform classification of forest sites within the upper Coastal Plain of South Carolina. Bulletin of the Torrey Botanical Club 111: 349–60.
Kantrud, H. A., J. B. Millar, and A. G. van der Valk. 1989. Vegetation of wetlands of the prairie pothole region. p. 132–87. In A. G. van der Valk (ed.) Northern Prairie Wetlands. Iowa State University Press, Ames, IA, USA.
Keough, J., G. R. Guntenspergen, and J. Grace. 1990. Vegetation and hydrologic characteristics of Carolina bays. Savannah River Ecology Laboratory, Aiken, SC, USA.
Kirkman, L. K. 1992. Cyclical vegetation dynamics in Carolina bay wetlands. Ph.D. Dissertation. University of Georgia, Athens, GA, USA.
Kirkman, L. K. 1995. Impacts of fire and hydrological regimes on vegetation in depression wetlands of Southeastern USA. p. 10–20. In S. I. Cerulean and R. T. Engstrom (eds.) Fire in Wetlands: A Management Perspective. Proceedings of the 19th Tall Timbers Fire Ecology Conference, Tall Timbers Research Station, Tallahassee, FL, USA.
Kirkman, L. K., P. C. Goebel, L. West, M. B. Drew, and B. J. Palik. 2000. Depressional wetland vegetation types: a question of plant community development. Wetlands 20: 373–85.
Kirkman, L. K., R. F. Lide, G. Wein, and R. R. Sharitz. 1996. Vegetation changes and land-use legacies of depression wetlands of the western Coastal Plain of South Carolina: 1951–1992. Wetlands 16: 564–76.
Kirkman, L. K. and R. R. Sharitz. 1993. Growth in controlled water regimes of three grasses common in freshwater wetlands of the southeastern USA. Aquatic Botany 44: 345–59.
Kirkman, L. K. and R. R. Sharitz. 1994. Vegetation disturbance and maintenance of diversity in intermittently flooded Carolina bays in South Carolina. Ecological Applications 4: 177–88.
Lide, R. F., B. G. Meentemeyer, J. E. Pinder, III, and L. M. Beatty. 1995. Hydrology of a Carolina bay located on the Upper Coastal Plain of western South Carolina. Wetlands 15: 47–57.
Mulhouse, J. M., L. E. Burbage, and R. R. Sharitz. 2005a. Seed bank-vegetation relationships in herbaceous Carolina bays: responses to climatic variability. Wetlands 25: 738–47.
Mulhouse, J. M., D. De Steven, R. F. Lide, and R. R. Sharitz. 2005b. Effects of dominant species on vegetation change in Carolina bay wetlands following a multi-year drought. Journal of the Torrey Botanical Society 132: 411–20.
Poiani, K. A. and W. C. Johnson. 1991. Global warming and prairie wetlands: potential consequences for waterfowl habitat. BioScience 41: 611–18.
Radford, A. E., H. E. Ahles, and C. R. Bell. 1973. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, NC, USA.
Reed, P. B., Jr. 1988. National list of plant species that occur in wetlands: national summary. US Fish and Wildlife Service, Washington, DC, USA. Biological Report 88(24).
Russell, K. R., D. C. Guynn, Jr., and H. G. Hanlin. 2002. Importance of small isolated wetlands for herpetofaunal diversity in managed, young growth forests in the Coastal Plain of South Carolina. Forest Ecology and Management 163: 43–59.
Schalles, J. F. and D. J. Shure. 1989. Hydrology, community structure, and productivity patterns of a dystrophic Carolina bay wetland. Ecological Monographs 59: 365–85.
Semlitsch, R. D. and J. R. Bodie. 1998. Are small, isolated wetlands expendable? Conservation Biology 12: 1129–33.
Shaffer, P. W., C. A. Cole, M. E. Kentula, and R. P. Brooks. 2000. Effects of measurement frequency on water-level summary statistics. Wetlands 20: 148–61.
Sharitz, R. R. 2003. Carolina bay wetlands: unique habitats of the Southeastern United States. Wetlands 23: 550–62.
South Carolina State Climatology Office. 2004. General climate description and summaries for South Carolina. SC Department of Natural Resources, Columbia, SC, USA. http://www.dnr.state.sc.us/climate/sco/.
SPSS Inc. 1999. SYSTAT Version 9. SPSS, Inc., Chicago, IL, USA.
Sun, G., T. J. Callahan, J. E. Pyzoha, and C. C. Trettin. 2006. Modeling the climatic and subsurface stratigraphy controls on the hydrology of a Carolina bay wetland in South Carolina, USA. Wetlands 26: 567–80.
Sun, G., S. G. McNulty, J. P. Shepard, D. M. Amatya, H. Riekerk, N. B. Comerford, W. Skaggs, and L. Swift, Jr. 2001. Effects of timber management on the hydrology of wetland forests in the southern United States. Forest Ecology and Management 143: 227–36.
Taylor, B. E. and M. J. Brooks. 1994. Modern climate and water level predictability in a Carolina bay on the SRS: a baseline for interpreting the geoarchaeological record. p. 33–50. In Savannah River Archaeological Research Program (ed.) Annual Review of Cultural Resource Investigations, South Carolina Institute of Archeology and Anthropology University of South Carolina, Columbia, SC, USA.
Taylor, B. E., D. A. Leeper, M. A. McClure, and A. E. DeBiase. 1999. Ecology of aquatic invertebrates and perspectives on conservation. p. 167–95. In D. P. Batzer, R. P. Rader, and S. A. Wissinger (eds.) Invertebrates in Freshwater Wetlands of North America: Ecology and Management. John Wiley & Sons, Inc, New York, NY, USA.
van der Valk, A. G. and C. B. Davis. 1978. The role of seed banks in the vegetation dynamics of prairie glacial marshes. Ecology 59: 322–35.
Workman, S. W. and K. W. McLeod. 1990. Vegetation of the Savannah River Site: major community types. U.S. Department of Energy, Savannah River Ecology Laboratory, Aiken, SC, USA. SRO-NERP-19.