Pattern of nutrient availability and plant community assemblage in Everglades Tree Islands, Florida, USA
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We address the relative importance of nutrient availability in relation to other physical and biological factors in determining plant community assemblages around Everglades Tree Islands (Everglades National Park, Florida, USA). We carried out a one-time survey of elevation, soil, water level and vegetation structure and composition at 138 plots located along transects in three tree islands in the Park’s major drainage basin. We used an RDA variance partitioning technique to assess the relative importance of nutrient availability (soil N and P) and other factors in explaining herb and tree assemblages of tree island tail and surrounded marshes. The upland areas of the tree islands accumulate P and show low N concentration, producing a strong island-wide gradient in soil N:P ratio. While soil N:P ratio plays a significant role in determining herb layer and tree layer community assemblage in tree island tails, nevertheless part of its variance is shared with hydrology. The total species variance explained by the predictors is very low. We define a strong gradient in nutrient availability (soil N:P ratio) closely related to hydrology. Hydrology and nutrient availability are both factors influencing community assemblages around tree islands, nevertheless both seem to be acting together and in a complex mechanism. Future research should be focused on segregating these two factors in order to determine whether nutrient leaching from tree islands is a factor determining community assemblages and local landscape pattern in the Everglades, and how this process might be affected by water management.
KeywordsBiogeochemical hot-spot N:P ratio Phosphorus Self-assembly Spatial patterns Landscape ecology Wetlands
We would like to acknowledge the assistance in field and lab provided by the following members of our lab: Pablo Ruiz, David Reed, David Jones, and Josh Walters. Dr. Krish Jayachandran, Seema Sah, and Darcy Stockman provided invaluable assistance on the soil analyses. Financial support for the project came from the Critical Ecosystems Science Initiative (CESI) of the National Park Service, US Department of Interior. The research was enhanced by collaboration with the Florida Coastal Everglades Long-Term Ecological Research program (funded by the National Science Foundation, # DEB-9910514 and DBI-0620409). This is SERC Contribution # 516.
- Dean, W. E., 1974. Determination of carbonate and organic matter in calcareous sediments and sedimentary rocks by loss on ignition: comparison with other methods. Journal of Sedimentology Petrology 44: 242–248.Google Scholar
- German, E. R., 2000. Regional evaluation of evapotranspiration in the Everglades. USGS Water-Resources Investigation Report 00-4217. US Geological Survey, Washington.Google Scholar
- Golterman, H. L., 2004. The Chemistry of Phosphates and Nitrogen Compounds in Sediment. Kluwer Academic Publisher, Dordrecht.Google Scholar
- Grace, J. B. & D. Tilman, 1990. Perspective on Plant Competition. Academic Press, San Diego.Google Scholar
- Jayachandran, J., S. Sah, J. P. Sah & M. S. Ross, 2004. Characterization, biogeochemistry, pore water chemistry and other aspects of soils in tree islands of Shark slough. In Ross, M. S. & D. T. Jones (eds), Tree Islands in the Shark Slough Landscape: Interactions of Vegetation, Hydrology and Soils. Final Report. Everglades National Park, Homestead: 17–29.Google Scholar
- McLean, E. O., 1982. Soil pH and lime requirement. In Page, A. L., R. H. Miller & R. D. Keeney (eds), Methods of Soil Analysis. 2. Chemical and Microbiological Properties. Agronomy Monograph 9, 2nd ed. Soil Science Society of America, Madison, Wisconsin: 199–209.Google Scholar
- National Research Council (NRC), 2003. Does Water Flow Influence Everglades Landscape Patterns?. The National Academies Press, Washington.Google Scholar
- Orem, W. H., D. A. Willard, H. E. Lerch, A. L. Bates, A. Boyland & M. Comm, 2002. Nutrient geochemistry of sediments from two tree islands in water conservation area 3B, the Everglades, Florida. In Sklar, F. H. & A. G. van der Valk (eds), Tree Islands of the Everglades. Kluwer Academic Publishers, Netherlands.Google Scholar
- Ross, M.S. & J. P. Sah, (2011). Forest resource islands in a sub-tropical marsh: soil-site relationships in Everglades hardwood hammocks. Ecosystesms. doi: 10.1007/s10021-011-9433-y.
- Sklar, F. H. & A. G. van der Valk, 2002. Tree islands of the Everglades: an overview. In Sklar, F. H. & A. G. van der Valk (eds), Tree Islands of the Everglades. Kluwer Academic Publishers, Netherlands.Google Scholar
- ter Braak, C. J. F., 1991. CANOCO—a FORTRAN Program for Canonical Community Ordination, Correspondence Analysis, Principal Component Analysis, and Redundancy Analysis. Microcomputer Power, Ithaca.Google Scholar
- ter Braak, C. J. F. & P. Šmilauer, 2002. CANOCO Reference Manual and CanocoDraw for Windows User’s Guide: Software for Canonical Community Ordination (Version 4.5). Microcomputer Power, Ithaca.Google Scholar
- Tilman, D., 1982. Resource Competition and Community Structure. Princeton University Press, Princeton.Google Scholar
- Tilman, D., 1997. Mechanism of plant competition. In Crawley, M. J. (ed.), Plant Ecology, 2nd ed. Blackwell Science, Oxford: 239–261.Google Scholar
- Vitousek, P. M. & L. R. Walker, 1987. Colonization, succession and resource availability: ecosystem-level interactions. In Gray, A. J., M. J. Crawley & J. P. Edwards (eds), Colonization, Succession and Stability. Blackwell Scientific Publications, Oxford: 201–224.Google Scholar
- Watts, D. L., M. J. Cohen, J. B. Heffernan, & T. Z. Osborne, 2010. Hydrologic modification and the loss of self-organized patterning in the ridge-slough mosaic of the Everglades. Ecosystems 13: 813–827.Google Scholar