Effects of an agri-environment scheme on farmland biodiversity in Ireland

Abstract

Agri-environment measures cover at least 20% of the EU's farmland, a proportion rising to approximately 30% in Ireland. A study, investigating effects on biodiversity of Ireland's Rural Environment Protection Scheme (REPS) is described. Field margin flora and Carabidae (ground beetle) fauna were surveyed on 60 paired agreement and non-agreement farms. Greater variation was observed amongst surveyed non-agreement farms: the most species-rich and species-poor farms were all non-agreement. On surveyed grassland farms, average plant species richness was significantly higher on non-agreement than on agreement farms. Otherwise, few differences between average species richness and abundance on agreement and non-agreement farms were revealed. In ordination analysis of the flora and carabidae data factors largely independent of recent management, such as hedge age and gappiness, were most important in explaining observed variation. The study concluded that the scheme has not significantly benefited the groups surveyed, and suggests that the generic measures in such horizontal schemes may be better suited to addressing landscape-level issues such as water pollution, with biodiversity objectives for high nature value areas being more effectively achieved by targeted zonal schemes. Baseline data and long-term monitoring of measurable objectives are essential for effective evaluation, both to better tailor these innovative schemes to their aims, and to clearly demonstrate their benefits.