Date of Award
Master of Science (MS)
Dr. Elmer J. Finck
The development of informed management practices and insightful research depends not only on an understanding of species natural history and ecology, but information regarding the distributions of these species and how they interact with adjacent taxa. The study of a species distribution can become complicated if the geographic variation within the species is not understood. Pocket gophers, including those in the genus Geomys, display morphological and chromosomal variation across their range, even within the same species. Genetic techniques, including Amplified Fragment Length Polymorphism (AFLP), have clarified population relationships and characterized zones of contact. Previous studies have suggested 2 species and up to 5 subspecies of Geomys in Kansas. Researchers have documented 1 contact zone in Osborne County between a population with small body size and lighter pelage in the west and a population that is larger and darker in the east. However, there has been little consensus over the taxonomic status of these 2 populations. Also, there has not been sufficient research that documents the presence and distribution of other distinct Geomys populations in Kansas. For my study, 143 pocket gophers were captured from throughout Kansas. Tissue samples of these specimens, including 1 additional sample from Lincoln County, Nebraska, were analyzed with AFLP by using 6 primer pair combinations. These data were then evaluated by using Principle Coordinate Analysis, the program STRUCTURE, and an unrooted phylogram generated by using distance values to determine the presence of genetically distinct taxa, their distributions in Kansas, and any level of genetic admixture among populations. Results were considered following the genetic species concept. Consensus among all 3 analyses suggested the presence of 4 genetically cohesive populations in Kansas with each having different degrees of genetic isolation. My research suggested that the northwestern taxonomic group, Geomys halli, was isolated genetically and was functioning as a species. Other taxa in Kansas were suggested to include, G. bursarius majusculus (eastern), G. b. industrius or major (south central), and G. jugossicularis (southwestern). The northwestern population was likely in secondary contact with the southwestern and eastern populations, suggested by a zone of sympatry, 1 hybrid, and little admixture. Determination of taxonomic rank was limited because the interactions among these taxa are unknown outside of Kansas.
Schwenke, Zachary J., "Distribution and genetic structure of pocket gophers (Genus Geomys) in Kansas" (2010). Master's Theses. 180.
© 2010 Zachary Schwenke