Impacts of an agri-environment field margin prescription on the flora and fauna of arable farmland in different landscapes

Roughly 20% of the European Union's farmland is under some form of agri-environment scheme to counteract the negative impacts of modern agriculture on the environment. The associated costs represent about 4% (1.7 billion euros) of the European Union's total expenditure on the Common Agricultural Policy and are expected to rise to 10% in the near future. Although agri-environment schemes have been implemented in various countries for well over a decade, to date no reliable, sufficiently replicated studies have been performed to test whether such measures have the presumed positive effects on biodiversity. Here we present the results of a study evaluating the contribution of agri-environment schemes to the protection of biodiversity in intensively used Dutch agricultural landscapes. We surveyed plants, birds, hover flies and bees on 78 paired fields that either had agri-environment schemes in the form of management agreements or were managed conventionally. Management agreements were not effective in protecting the species richness of the investigated species groups: no positive effects on plant and bird species diversity were found. The four most common wader species were observed even less frequently on fields with management agreements. By contrast, hover flies and bees showed modest increases in species richness on fields with management agreements. Our results indicate that there is a pressing need for a scientifically sound evaluation of agri-environment schemes.