Tree Islands of the Everglades

Chapter 16.
Spatial Simulations of Tree Islands for Everglades Restoration

Yegang Wu, Ken Rutchey, Weihe Guan, Les Vilchek and Fred H. Sklar
email: ywu@sfwmd.gov
South Florida Water Management District, Everglades Department, Watershed Management Division, 3301 Gun Club Road, West Palm Beach, FL 33406 U.S.A.

From Tree Islands of the Everglades edited by Fred H. Sklar (South Florida Water Management District) and Arnold G. van der Valk (Iowa Lakeside Laboratory)

Abstract

The Florida Everglades, a vast wetland dotted with diverse tree islands, is a uniquely difficult wetland to manage because of competing urban, agricultural and environmental water demands. Tree islands in certain sections of the Everglades have experienced altered hydroperiod due to water management practices that has, at times, caused tree island vegetation to die. This study uses the Everglades Landscape Vegetation Model (ELVM) to investigate whether an observed trend in tree island loss is reversible, and if tree islands can be used as performance measures or ecological indicators for the success of Everglades restoration actions. The ELVM was developed and designed to be a tool to understand the spatial and temporal interactions among vegetation, water, fire and nutrients. Simulation results from this model suggest that hydroperiod is a major factor contributing to tree island development and stability in the Everglades. Simulations of the ELVM indicated that tree island water depths greater than 30 cm and hydroperiods longer than 150 days were decreasing tree island survival rates. According to the model, about 60% of tree islands lost in the Water Conservation Area 2A (WCA-2A) in the last few decades can be recovered by restoring the natural hydrological regimes. As a result, tree island health could be used as a performance measure to evaluate the effects of various hydrological restoration alternatives in the Everglades.

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