PARENT SESSION
Organized Oral Session 6: Development of landscape heterogeneity at multiple scales in wetlands
Organizer(s): B Warner and A van der Valk
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 516 A, Level 5, Palais des congrès de Montréal
Focused redistribution of nutrients and the development of tree islands in the Florida Everglades.
Wetzel, Paul1, van der Valk, Arnold2, Newman, Sue3, Gawlik, Dale4, Gann, Tiffany5, Coronado-Molina, Carlos6, 1 Smith College, Northampton, Massachusetts2 Iowa State University, Ames, Iowa3 South Florida Water Management District, West Palm Beach, Florida4 Florida Atlantic University, Boca Raton, Florida5 Florida International University, Miami, Florida6 South Florida Water Management District, West Palm Beach, Florida
ABSTRACT- The Florida Everglades is an oligotrophic wetland with tree islands as one of its most prominent landscape features. Total soil phosphorus concentrations on tree islands can be 6 to 100 times greater than phosphorus levels in the surrounding marshes and sloughs, making tree islands nutrient hot spots on the landscape. The focused redistribution of limiting nutrients, especially P, is hypothesized to control tree island maintenance and development after a tree island has formed. A model is proposed for the development of tree islands in the Everglades that identifies a number of mechanisms for redistributing nutrients. These mechanisms include surface and ground water flows, higher evapotranspiration rates on tree islands, guano deposited by wading and other birds and mammals, higher deposition rates of windborne particulates, and dissolution of bedrock by tree exudates. Because of increased primary production and peat accretion rates, the redistribution of P to tree islands can result in an increase in both their elevation and size. As the islands expand, they are able to support a greater number of plant and animal species. Tree islands in the Everglades provide an example of landscape level patterns created by the focused local redistribution of limiting nutrients. The proposed model implies that the preservation of tree islands, and ultimately the Everglades landscape, requires the maintenance of these phosphorus redistribution mechanisms.©
Key words: hot spots, phosphorus, patterned wetlands