Spatial scaling of pocket gopher (Geomyidae) density
Additional Document Info
Pocket gophers have been considered as both serious pests to management of natural resources and critically important to the function of ecosystems. Assessments of their positive and negative impacts have relied largely on population density and behavior. However, 100 reported estimates of pocket gopher density from 32 published studies varied 415-fold from low to high density, and much of this variation can be explained by the 1,000-fold range in spatial extent of study area. Unlike mammalian carnivores, however, body mass explained a significant portion of the variation in density, even after adjusting density by size of the study area. Nearly all variation in density can be explained by study area and female body mass estimated at the corresponding study site. Residual variation in density differed significantly but not substantially among categories of dominant vegetation and land use, and among species. Pocket gopher density is spatially dependent, and therefore should not be compared among species, populations, or localities without defining the estimate to spatial scale. Further research across large areas and a range of conditions will be required to fully understand the factors that influence distribution and abundance of gophers.