Kayla N. Key


The definition of a species has been argued extensively by philosophers and biologists resulting in the development of many different concepts which often contradict each other. An integrative approach using multiple types of data (e.g, morphological, ecological, behavioral, genetic) may be the most successful at correctly assigning taxonomic levels.Here, we use an integrative approach of ecological niche modeling and molecular genetics to investigate the taxonomy of a state imperiled gartersnake subspecies, Thamnophis sirtalis annectens, using ecological niche modeling and molecular phylogenetics analyses. Recently, it was given a conservation rank of S2 (imperiled) in the state of Texas and those that are familiar with it have suggested that its numbers are dwindling. Using ecological niche modeling and mtDNA sequence data we begin to understand the natural and evolutionary history of T. s. annectens. The results of this study provided additional information on the ecology and potential habitat range of T. s. annectens as well as information on the phylogenetic systematics of this subspecies. Our ecological niche model indicates areas where conservation efforts for T. s. annectens should be focused as well as important environmental variable such as landcover and geology that T. s. annectens prefers. When including T. s. annectens in a comparative niche model, this subspecies primarily occupies distinctly different habitat than the red-sided gartersnake, T. s. parietalis, which also occurs in Texas. Statistical analysis indicated that T. s. annectens occupies as significantly different ecological niche than T. s. parietalis. Similarly, the genetic data indicate that T. s. annectens can be differentiated from T. s. parietalis and T. s. sirtalis, however this difference is greatest between T. s. sirtalis. While this work has told us much about T. s. annectens, more is left to be learned including ground-truthing our ecological niche model. Collecting additional genetic data to verify the phylogenetic relationships we have hypothesized here should also be done in the future. Regardless, this work indicates T. s. annectens may be distinct both genetically and ecologically and provides conservation managers with niche models that will assist in locating the optimal habitat required by this subspecies.

Date of publication

Spring 6-1-2015

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Biology Commons