Freshwater mussels represent one of the most imperiled faunal groups on the planet and are critical to freshwater ecosystems. If mussel species are not carefully defined, our conservation plans may miss differences in the habitat needs of different species and the conservation strategies may not be as successful. Because ecological niche models can be used to provide evidence to support similar or dissimilar ecological niches and habitat requirements, I used modelling to forecast suitable habitat for Fusconaia askewi and F. lananensis, two purported threatened Texas species. The modeling results indicated that these species are not ecologically different. Based upon this finding and other information, I treated F. askewi and F. lananensis as synonymous, with F. lananensis as the junior synonym. I combined the occurrence records for F. askewi and F. lananensis to make one ecological niche model for F. askewi. I then ground-validated the model by sampling 25 sites throughout East Texas. My model successfully located F. askewi in five previously unsampled areas, and forecasted suitable habitat in East Texas. On average, the sites where F. askewi was present were significantly higher in habitat suitability than the sites where F. askewi was absent. My study is noteworthy for using a high-resolution, multivariate approach to ecological niche modeling of riverine habitats, which was used to test whether two putative species are ecologically differentiated and to make an improved ecological niche model that combines equivalent entities into a single model. My approach can be used in other studies of closely related groups.

Date of publication

Fall 12-5-2019

Document Type




Persistent identifier


Committee members

Joshua Banta, Lance Williams, Neil Ford


Master of Biology

Included in

Biology Commons