This research compares food web structure of the Everglades to that of two similar karstic wetland complexes in the Caribbean. In the Everglades, we have demonstrated that wetlands of the Everglades display an unusual Eltonian pyramid of biomass, with very large standing crops of primary producers (periphyton) but relatively small standing crop of aquatic macroinvertebrates and very small standing crops of fishes. Data suggest that nutrient limitation, periodic drying and high abundance of calcium ions play a key role in creating this 'distinctive' food-web pattern of the Everglades. This research examines food web structure in wetlands of the Sian Ka'an Bioreserve, Quinta Roo, Mexico and New River Lagoon, Orange Walk, Belize to determine whether this unusual biomass pyramid is characteristic of karstic wetlands. Our preliminary results underscore the striking similarities in the food-web structure and ecosystem patterns in karstic wetlands from these areas of the Yucatan with wetlands in South Florida. Although the species are different in these two regions and they have relatively independent histories over geological time, we propose that the similar underlying geologic characteristics of these two regions (marine limestone) yield convergence in ecosystem function.