What is the aim of the review?
To systematically collate and synthesise published and unpublished evidence in order to examine the effect that different land-based schemes (especially agri-environment) and their prescriptions have on (a) total farmland bird densities and (b) individual species densities within the U.K.

Who's in the review team?

• Philip Roberts (Lead reviewer) - Centre for Evidence-Based Conservation
• Andrew Pullin

At what stage is the review?
This review is now complete.

What is the rationale?
Farmland bird species have suffered considerable population declines and range restrictions over the past three decades. The combination of agricultural intensification, especially after the U.K. joined Europe and the Common Agricultural Policy, weed control through the increased use of herbicides, the change from spring sown crops to autumn cropping systems and increased stock densities are all agreed to be primary causes of this dramatic decline.

Based on large scale monitoring across Europe, the value of agri-environment schemes have been questioned due to mixed results across plant, invertebrates and bird species (Kleijn, et al. 2006). This systematic review seeks to clarify the situation within the UK, by assessing the available evidence within the public domain on the effectiveness of land-based schemes (incl. agri-environment schemes) at conserving farmland bird species densities.

Natural England (formerly English Nature) established the need for a systematic review to evaluate the effectiveness of land-based schemes and their individual prescriptions at increasing farmland bird species density. The specific question was identified in consultation with The Royal Society for the Protection of Birds (RSPB) and the Countryside Council for Wales , who also chose the target bird species reviewed in this document.

How were the results obtained?
A number of electronic databases were searched for information using a range of search terms. Internet searches were conducted in order to retrieve any relevant grey literature. The websites of several major UK conservation organisations were also searched for useful publications. 3070 unique references were identified through the search strategy; 30 of these were accepted into the final review having met all inclusion criteria.

What did the review find?
To read more about this review, its findings, and the implications for conservationists and researchers, please see the Summary or Full Report.

Comments?
If you would like to comment on any aspect of this review, please email us. Your feedback is appreciated.