Niche Modeling of Eight Crayfish Species in Texas

Freshwater species make up ~10% of all known species and occupy less than one percent of earth’s habitat, which is being degraded by human usage. Crayfish have a large impact on their aquatic or terrestrial environment and can serve as a health indicator of aquatic environments, as they generally require undegraded environments. In many habitats, crayfish make up more than half of the macroinvertebrate biomass, and play important ecological roles, as a food resource for both aquatic and terrestrial species, as predators of fish and invertebrates, and as bioprocessors of vegetation and detritus. The objective of this project was to model the habitats that Texas crayfish inhabit. These models were run for the species: Procambarus clarkii, Procambarus acutus, Procambarus simulans, Procambarus texanus, Procambarus fayettei, Lacunicambarus ludovicianus, Faxonius nais and Faxonius occidentalis. Crayfish are an understudied taxon, especially in Texas. To model species distributions throughout Texas, environmental data and species occurrence locations were combined using the software Maxent to make maps of habitat suitability for each species across the entire landscape. Some habitat associations for the various species had reoccurring themes, specifically those for: precipitation seasonality, available water capacity, percent clay, organic matter and baseflow. Future work with central Texas crayfish can use the results of this study to compare niches and understand where competition and invasion could affect populations of native crayfish