Density-Dependent Responses of Gray-Tailed Voles to Mowing

Abstract

Voles (Microtus spp.) commonly inhabit forage crops and may cause excessive damage to these crops. However, cover removal by mowing or haying may cause vole populations to decline. To determine if gray-tailed voles (M. canicaudus) responded to mowing of alfalfa in a density-dependent manner, we livetrapped 4 populations in each of low- ( 90) 0.2-ha enclosures before and after mowing in 1992. Survival rates of both sexes, population size and growth rates, and proportion of total captures that were recruits declined (P 0.22). Greater than 50% of dispersing adult females were pregnant, and we suggest that mowing disrupted social organization of voles causing some animals to abandon home ranges or territories. Although mowing reduces populations of gray-tailed voles and disrupts social organization, the high reproductive potential of the species enables populations to recover rapidly to premowing levels