Optimization of the open-hole method for assessing pocket gopher, Thomomys spp., activity
Richard M. Engeman, Dale L. Nolte, Stephen Bulkin · The Canadian Field-Naturalist · 1999
Optimization of the open-hole method for assessing pocket gopher, Thomomys spp., activity.Canadian Field-Naturalist 113(2): 241-244.The open-hole method is widely used for monitoring activity of pocket gophers (Thomomys spp.) in western forests.We examined the open-hole method in a field study to optimize the number of holes to open and the number of burrow systems to observe.Sensitivity of assessing burrow system activity was minimally affected if two of three opened holes in each system were monitored, whereas there was a 20% decrease in sensitivity if only one hole was monitored.For general activity assessment purposes, a random sample of 30 burrow systems with two burrows opened per system appears to be an optimum mix to achieve sensitivity in activity estimates, without producing excessive labor in the field.