ASSESSING THE CONSERVATION NEEDS OF NATIVE TEXAS CRAYFISH SPECIES THROUGH DISTRIBUTION ANALYSIS AND SPECIES DISTRIBUTION MODELING

Crayfish have essential roles in ecosystems because they are ecosystem engineers and keystone species. However, crayfish species are threatened by degradation and loss of habitats, introduction of invasive species, and high levels of endemism. Texas provides no legal protections for crayfish, despite its large number of species and endemics in the state. The overall goal of this study is to clarify the distributions of native Texas crayfish species using literature records, citizens science, and field sampling data, and highlight species in need of more conservation research. Occurrence records from all collected data were combined to visualize the distributions of species through time and test for significant shifts in their ranges. Furthermore, to understand how suitable habitat will change in the future, species distribution models (SDMs) were created using soil, current climate, and future climate layers for three crayfish species with different ecologies: Creaserinus hedgpethi, Lacunicambarus ludovicianus, and Procambarus acutus. The time interval maps for 51 Texas crayfish species showed complex patterns of observations through time. Additionally, the tests for range shifts suggested that more than half of Texas crayfish species shifted through time. The SDMs also showed varied results: two of the three species showed expanded suitable habitat in the future; whereas, one (P. acutus) showed reduced future suitable habitat within Texas. This study marks the first comprehensive review of Texas crayfish in almost 20 years. In the future, more field sampling and physiological research should be employed to validate the findings of this study.