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Ecology and Distribution of Pocket Gophers (Geomyidae) in Colorado

Miller, Richard S.
Ecology 1964 v.45 no.2 pp. 256-272
Geomys bursarius, Thomomys bottae, aggression, altitude, body size, gophers, habitats, latitude, soil, Colorado
The general distribution of the family geomyidae in North America is limited only by suitable soils, although a particular species may be also be limited by climatic or other factors associated with altitude and latitude and by interspecies competition. A study was made of the factors affecting the distributions of the pocket gophers Thomomys bottae, T. talpoides, Geomys bursarius, and Cratogeomys castanops in Colorado. The most critical factors in the relationships among pocket gophers are soil tolerance and competition. All four species in Colorado prefer deep light soils,but their ranges of tolerance vary, with the result that interspecies competition consists of the fundamental niche of one species being a proper subset of another. In each combination of competitive and is able to displace the other speices to less favorable habitats. The relationship among the four species in competitive ability is G. bursarius > C. castanops > T. bottae > T. talpoides. Possible mechanisms of competition are discussed in relation to body size, territory, aggression, and dispersal.