Land Use Relationships for a Rare Freshwater Mussel Species Endemic to Central Texas

We assessed the influence of geology, land use, and other features on the occurrence of the rare freshwater mussel smooth pimpleback, Quadrula houstonensis, in the Leon River, Texas. Boosted regression trees were used to assess the relationships between the species' occurrence and potential explanatory variables based on field data from 52 sampling locations. The individual variables that best explained prevalence for this species were downstream distance from reservoirs, percentage of shrubland within the riparian buffer, and percentage of alluvium and aquifer bearing rock-types. These results indicate that smooth pimpleback may be sensitive to flow modification and changes in land use that increase sedimentation. The application of similar modeling efforts to other rare species in this region could help in their management and conservation.