Effects of higher-tier agri-environment scheme on the abundance of priority farmland birds

Agri-environment schemes (AES) are the main policy mechanism available for reversing the widespread declines of European farmland biodiversity. We assessed the impact of AES land management on the abundance of bird species whose populations have declined as a consequence of agricultural intensification. The AES involved the deployment of a whole-farm package of wildlife-friendly land management options covering an average of 7% of the farmed area. The study was conducted across three English regions and focused on species of conservation concern and on a wider suite of farmland birds comprising the UK Government's Farmland Bird Indicator (FBI). Changes in avian abundance on AES farms were compared with those measured across the wider farmed landscape as part of a national bird monitoring scheme. Twelve out of 17 priority species, and the FBI, showed more positive changes in abundance on AES farms in at least one region. Eight species exhibited sustained responses to AES management in at least one region, and eight species exhibited a temporary enhancement in abundance in at least one region. Temporary responses to AES management followed a large scale failure of key AES options to establish during successive wet and cold summers, and involved species known to depend on the habitats provided by these options. In order to offset ongoing declines of FBI species in the wider farmed countryside of 2.3-4.1% per annum, we estimate 26-33% of FBI populations would need to be subject to AES-type management. This study demonstrates the potential for AES land management to substantially enhance the abundance of priority farmland birds and highlights the need for option packages that are resilient to the impacts of variable weather conditions.