Influence of Vegetation on Invertebrate Communities in Grazed Freshwater Wetlands in South-central Florida

Grazing lands and rangelands are increasingly recognized as an important alternative to other developed land uses for sustaining ecological communities in Florida, the rest of the southeastern United States, and other regions. It is important to understand factors that influence ecological communities on private grazing lands, especially in areas with abundant wetlands, which are often sensitive habitats. This study examined the effects of different vegetation types and simulated grazing (clipping) on the abundance, diversity, and composition of the invertebrate community in seasonally flooded, isolated wetlands on a cattle ranch in south-central Florida. We compared invertebrate communities in wetland areas dominated by two different types of vegetation: emergent macrophytes (Pontederia cordata [Pickerelweed]) and grasses (primarily Luziola fluitans [Southern Watergrass]). There was a trend toward greater abundance and diversity of invertebrates in grass-dominated communities. Experimental removal of vegetation to simulate heavy grazing significantly decreased the abundance and diversity of invertebrates. It also shifted the community composition of invertebrates to favor members of Diptera and Ostracoda. Management practices in grazed wetlands that use light or intermediate levels of grazing, or that foster a greater diversity of vegetative cover, may support more diverse and populous wetland invertebrate communities.