Agri-environment management for corncrake Crex crex delivers higher species richness and abundance across other taxonomic groups

This study tested whether agri-environment scheme (AES) management for corncrakes in the UK is associated with higher diversity or abundance of non-target flora and fauna relative to similar land outside AES management. The species richness and abundance of forbs, butterflies, bumblebees and foliar arthropods were compared on 101 paired control-treatment plots across the two AES measures for corncrakes: provision of tall vegetation throughout the breeding season (Early and Late Cover; ELC) and delayed mowing (DM) of hay or silage fields. There were significant positive effects of AES management for the species richness of forbs, and abundance of late-season flowers, butterflies, bumblebees and the majority of foliar arthropod groups on one or both AES measures. Significant negative effects of AES were found in only two cases: forb species richness (ELC only) and the abundance of springtails (DM only). For the remaining species and groups studied there was either no effect of AES or no clear difference due to strong AES × season interactions. The magnitude of the AES effects varied substantially both between taxonomic groups and the two measures for corncrake. Most of the positive effects were for common and widespread species, except for two rare bumblebees. The benefits resulted from the reduction in farmland management intensity associated with AES. While not beneficial to all taxonomic groups these results demonstrate that, in the case of corncrakes in the UK at least, well-designed AES measures targeted at a specific species do yield wider biodiversity benefits.

► AES management had positive effects for a wide range of invertebrate groups relative to similar non-scheme farmland.
► Plant species richness was higher on AES late-cut grasslands but lower on AES cover plots.
► Most positive effects were for common species except for two rare bumblebees.
► UK AES measures implemented for corncrake yield benefits for wider biodiversity.