The Effects of Habitat Structure on Winter Aquatic Invertebrate and Amphibian Communities in Pine Flatwoods Wetlands

Abstract

Natural disturbances play a critical role in structuring many ecosystems. In the southeastern United States, fire suppression and exclusion have removed the natural disturbance regime from many ecosystems, including ephemeral wetlands embedded within longleaf pine forests. We sampled aquatic invertebrate and amphibian communities in 21 pine flatwoods wetlands in northwest Florida from 2012 to 2014. Our objectives were to quantify amphibian and invertebrate community structure, identify differences in amphibian communities across an environmental gradient, and identify how invertebrate communities responded to wetland habitat characteristics. Amphibian communities were more diverse in wetlands with longer hydroperiods but were similar across wetlands with different vegetation structures. To examine the effects of wetland characteristics on aquatic invertebrate communities, we created a set of a priori models relating the abundance of isopods, chironomids, and damselflies to wetland characteristics. The best-approximating models indicated that isopods and damselflies were more abundant in wetlands that were not fire-suppressed. Similarly, total invertebrate abundance was higher in sections of wetlands with low canopy cover when compared to sections of the same wetlands with high canopy cover. Restoration of vegetation structure in wetlands that have experienced long-term fire suppression and wetlands that support longer hydroperiods should be a management priority.