LITTORAL-ZONE INVERTEBRATE COMMUNITIES AS AFFECTED BY A HABITAT RESTORATION PROJECT ON LAKE TOHOPEKALIGA, FLORIDA

Following an extreme drawdown of Lake Tohopekaliga in 1987 during which excessive organic substrate was removed, the lake was sampled for littoral invertebrates by dip net and corer during 1988 and 1989. The numbers of invertebrates (densities and taxa) associated with macrophytes in restored areas were less than they were in undisturbed (control) areas in 1988. One year later (1989), the densities of these invertebrates were greater in restored areas, but the number of taxonomic megagroups (families, orders or classes) were still higher in control areas. The densities and taxonomic diversities of bottom-dwelling (corer samples) invertebrates were consistently (1988 and 1989) greater in the restored areas. Chironomidae and Oligochaeta comprised more than 29% of the total invertebrate population. Important groups also included Palaemonidae, coenagrionidae, Baetidae, Caenidae, Hyalellidae and Hydrophilidae. The observed changes and differences in the invertebrate communities were generally attributed to changes and differences in macrophyte densities, ratios of submerged-floating to emergent plants, concentration of dead vegetation, ratios of air-breathing to gill-breathing invertebrates and fish predation. Fish predation was probably the single most important factor in shaping the restored invertebrate community.