Abstract

This study was initiated to investigate the distribution patterns of two species of pocket gophers, Thomomys umbrinus albicaudatus Hall and T. talpoides wasatchensis Durrant whose ranges come together in the Hobble Creek area, Utah. The effect of certain ecological factors upon their distribution was determined. The ecological factors included: vegetation and land use, soil, moisture and exposure, hybridization and interspecific competition. From morphological examination no interbreeding was detected even though the breeding seasons of the two species correspond. A limited area was found where the ranges of the two species are in contact. A lack of available moisture was determined to be a major factor inhibiting the distribution or talpoides in non-irrigated soils. Umbrinus is very versatile toward moisture and does not appear to be affected. Both species show a preference for sandy or gravelly-loam soils. Interspecific competition apparently inhibits the distribution of both species where the ranges come together. It is supposed that where only one species occurs that ranges will continue to be extended with talpoides being limited to the more moist areas. The other ecological factors are of no apparent significance to the distribution of either species except as they relate to the amount of available moisture.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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