Abstract:
Aquatic species are facing imperilment at a disproportionate rate compared to terrestrial species and thus higher probabilities of extinction. The southeastern United States has an exceptionally high level of freshwater biodiversity, supporting the majority of the nation’s fish, mussel, and crayfish species. Crayfish research, in particular, is significant to conservation efforts, as nearly half of the crayfish species in the southeastern United States are threatened. Through their signature burrowing strategy, many crayfish bridge the gap between aquatic and terrestrial communities, especially in floodplain habitats. Floodplains are highly heterogeneous and harbor a high diversity of species, yet our understanding of species-habitat relationships within these complex ecosystems remains incomplete and may hinder conservation. I studied floodplains in the Bogue Chitto Creek watershed in the Black Belt Prairie region of Alabama to investigate: 1) activity patterns of primary burrowing crayfish and 2) local and landscape level environmental factors that may affect burrowing crayfish distribution. In Chapter 2, I used motion-triggered digital photography to document activity patterns for two primary burrowing crayfish. I found that out-of-burrow activity was greatest at night and during periods of relatively cool groundwater temperatures and relatively warm air temperatures, which may be linked to thermal regulation. In Chapter 3, I examined relationships between burrowing crayfish presence and species composition and local hydrogeological factors. Results suggested an increased likelihood that crayfish were present at sites with a shallow water table, and that species composition was marginally associated with depth to groundwater and inundation duration. In Chapter 4, I investigated associations between burrowing crayfish presence and species composition and geomorphological factors. I found that crayfish were more likely to be present in areas that were not in the channel migration path, areas near streams with a greater sinuosity, areas with greater floodplain connectivity, and areas with less forested land use. The combined results of my studies in the Bogue Chitto Creek watershed suggest that projects embracing integrated, multidisciplinary approaches to surface and groundwater hydrology as drivers of biodiversity should be a priority for research related to the conservation of burrowing crayfish populations and communities.
