Creation of bunchgrass, sagebrush, and perennial grassland habitats within a semi-arid agricultural setting: Implications for small mammals

Native habitats of the semi-arid intermontane grasslands and shrub-steppe rangelands of the Pacific Northwest of North America are disappearing owing to agricultural, urban, and recreational development. A major small mammal occupying these habitats is the montane vole (Microtus montanus), along with the deer mouse (Peromyscus maniculatus), northwestern chipmunk (Neotamias amoenus), house mouse (Mus musculus), and two less common species at risk. To help restore these native habitats and small mammals, we tested three hypotheses (H) that non-crop habitats of native bunchgrasses, sagebrush (Artemisia tridentata), and perennial grasslands (alfalfa and mix of forage grasses) would: (H1) establish in an agricultural setting, (H2) conserve small mammal species, and (H3) limit vole damage to tree fruit production in orchards. Linear habitats of these non-crop treatments, within a semi-arid agrarian setting in south-central British Columbia, Canada, were sampled for all vascular plants and small mammals from 2006 to 2010. Mean abundance of bunchgrasses declined after the second year owing to competition from orchard herbs, but sagebrush and pasture grasses became well established, thereby partially supporting H1. Alfalfa established initially but then declined potentially owing to consumption by voles. Conservation of the three major small mammal species, but not less common species, partially supported H2. Alfalfa and pasture grasses provided optimum habitat for montane voles, but their high numbers did not result in feeding damage to tree fruit production, thereby supporting H3. Creation of non-crop habitats within as well as adjacent to agricultural settings should become a major endeavour to restore native habitats, enhance small mammal populations, and maintain biodiversity.