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Crop fields can provide habitat to a variety of wildlife and crop damage can result (Wywialowski 1996, 1998; Conover 1998). Among the vertebrates, damage can occur from numerous species of birds and mammals. Worldwide concern, however, has focused on rodents and a large number of species cause substantial agricultural losses each year (Witmer et al. 1995). After the advent of effective herbicides and "clean farming" practices in North America, however, many rodent problems became insignificant (Hines and Hygnstrom 2000). This is, in large part, because the fields were plowed each year, disrupting burrows and removing ground cover. The fields often lay bare a lengthy part of the year. The use of herbicides, plowing, and burning prevented the fields from developing the vegetative cover that wildlife needed for year-round food and shelter.
This situation has been changing in recent years. The use of conservation tillage or no-till agriculture is increasing across much of North America, in part because these methods conserve soil and water resources. Many problems can arise, however, and an integrated pest management strategy is needed to deal with weed, insect, and vertebrate pests that can proliferate and cause substantial damage in the no-till agriculture setting (Holtzer et al. 1996). When the ground is not plowed each year, crop residues are maintained, and surrounding areas provide good harborage for rodents, the potential exists for substantial increases in rodent populations and subsequent crop damage.
The microtine species group (Subfamily Microtinae, Nowak 1991) contains many species that are serious pests throughout the northern hemisphere. In North America, many of the pest species belong to the genus Microtus, commonly called voles or meadow mice. In this paper, we review the literature and provide background information on voles and the damage they cause. We also discuss management strategies that can help reduce agricultural damage by voles.