Impact of orchard vegetation management on small mammal population dynamics and species diversity

Voles of the genus Microtus feed on bark and vascular tissues of trees in fruit orchards across North America. Management of orchard floor vegetation with multiple applications of herbicide effectively altered habitat and reduced montane vole (M. montanus) populations in apple orchards near Summerland, British Columbia, Canada. Non-target populations of deer mice (Peromyscus maniculatus), northwestern chipmunks (Tamias amoenus), and Great Basin pocket mice (Perognathus parvus) appeared to respond positively to the treatment units. None of these non-target species was adversely affected by the actual herbicide treatments. Species diversity of small mammal communities in treated orchards was the same as that in untreated orchards and nearby old fields. Orchard agroecosystems with intensive vegetation management regimes appear to maintain diverse non-target small mammal communities.