Updated geographic distributions for Texas reptiles

Abstract

As is the case for many taxa in the Anthropocene, reptile conservation is challenged by an assortment of human-mediated factors. Distributional data for reptile species can be highly useful for informing conservation action. For example, species occurrence data can be used to model suitable habitat as well as quantify contraction, expansion, or shift in the distribution of a species. Texas, USA has a rich reptile fauna including one crocodilian, 32 testudine, 55 lacertilian, and 82 serpent species. However, literature pertaining to the distribution of these species has not been synthesized for over a decade. The goals of our study were to visually summarize all published distributional data for reptile species in the state with updated distribution maps; to tabulate all novel and historic distribution data that is absent from the last statewide synthesis; and to characterize any taxonomic, geographic, or temporal trends of distribution record reporting that have occurred in the state over the last decade. We discovered a total of 659 records that supplement the maps provided in the last statewide synthesis, 40% of which were found in published materials that predate that synthesis. Regarding distributional records published over the last decade, there was no apparent temporal trend – record reporting across years appeared to be stochastic. The number of records published for reptile families generally followed patterns of species richness, although several families had fewer or more records than would be expected. These results might be due to several factors including species biology, variable rates of potential range spread or contraction, and variable research attention (historically and contemporarily). Spatially, we found hot spots of record reporting in the southern, western, and northern portions of the state. We suspect these represent either a contemporary geographic bias of research attention, historically poor range characterization for reptile species occupying these regions, or a combination of both. We also found cold spots of record reporting in the northwestern portion of the Panhandle. These are likely due to natural patterns of reptile diversity as well as geographically biased research attention. Future work to be conducted on reptile distributions in Texas should include a thorough synthesis and revisiting of the voucher specimen data associated with these records.