Botanical changes in beetle banks.

Abstract

Beetle banks are grass-sown raised strips providing habitat for invertebrate predators of arable crop pests and other wildlife. The botanical species composition and diversity of a range of banks in southern UK were assessed for age-related change. Increasing diversity was found, with those over a decade old almost as diverse as conventional field margins. More grass but less herbaceous cover, and fewer nectar-providing plants, were found in banks compared with margins. Weeds were present at levels that could cause concern, although there is little evidence that beetle banks could be significant sources of crop invasion by economically threatening weeds. Few individual species appeared exclusively in banks. The dense vegetation within banks suggests that they can provide suitable refuge for predators for at least a decade, with greater diversity of benefit to other invertebrates. As simple, inexpensive features, beetle banks can divide large fields and enhance biodiversity, while requiring minimal management.