Adaptive management and targeting of agri-environment schemes does benefit biodiversity: a case study of the corn bunting Emberiza calandra

Abstract

Summary1. Agri-environment schemes (AES) are the main European policy response to biodiversity loss caused by agricultural intensification. Maximizing their effectiveness is a key policy challenge. Monitoring is essential to inform adaptation and improvement of schemes over time, and to understand how measures may need to vary across a species' range. 2. We measured changes in breeding abundance of a severely declining bird, the corn bunting Emberiza calandra, in response to AES in Scotland over 7 years and 71 farms. Two AES were monitored, one with general management for farmland birds, and one with targeted, adaptive management for corn buntings. We use these data to estimate the proportion of the population that AES must influence to halt the overall decline. 3. Corn buntings increased by 5AE6% per annum on farms in the targeted AES, showed no significant change on farms in the general AES, and declined by 14AE5% per annum on farms outside AES. 4. In arable-dominated areas, AES management that increased food availability reversed population declines. However, where a high proportion of corn buntings nested in grasslands, an additional AES option that delayed mowing was essential to achieving population increase. 5. Results suggest that approximately 72% of the corn bunting population in mainland Scotland must receive targeted AES management to halt the current decline. In 2009, only 24% was targeted in this way. 6. Synthesis and applications. AES measures are capable of reversing corn bunting declines in Scotland, and the same measures are likely to benefit a wide range of other taxa too, but require geographical targeting and flexibility to adapt and improve management options, backed by expert advice. Targeted AES provision to the required level for corn buntings will cost approximately £120 000 per annum, with 500-600 ha under appropriate management. This is 0AE02% of annual subsidies paid to Scottish farmers, and 0AE5% of land in the remaining mainland range of the corn bunting. These outcomes illustrate the value of AES monitoring studies to assess scheme effectiveness, identify improvements, and determine the scale of implementation required for reversing species declines.

Integrating quantitative and qualitative data in assessing the cost-effectiveness of biodiversity conservation programmes

“…Another recurrent theme was the need for improved advice on appropriate management and meaningful monitoring programmes linked closely to the objectives which have been set -sentiments that echo findings in other recent studies (e.g. Hart et al 2011;Perkins et al 2011;Armsworth et al 2012).…”

“…For example, in the case of farmland birds, Perkins et al (2011) report how bespoke monitoring was used to assess the effectiveness of a specific scheme in Scotland whilst Baker et al (2012) use more routinely collected monitoring data to identify spatial variation in scheme impacts across the UK. For more complex schemes involving multiple potential benefits, Mauchline et al (2012) and Pannell et al (2013) separately advocate the involvement of scheme participants in not only scheme design but also in undertaking monitoring activities.…”

“…Globally, most biodiversity conservation programmes are not currently evaluated in terms of their costs and benefits, or their rate of return on the original investment (Haddock et al 2007), though there have been some notable exceptions (see: Moran et al 1996;Metrick and Weitzman 1998;Cullen et al 1999;Cullen et al 2001;Finn et al 2009;Laycock et al 2009Laycock et al , 2011Perkins et al 2011;Baker et al 2012;Pannell et al 2013;Shwiff et al 2013;Cullen and White 2013). Assessing the cost-effectiveness of conservation programmes can be challenging for a number of reasons.…”

Should We Stay or Should We Go Now? What Happens to Small Mammals When Grass is Mown, and the Implications for Birds of Prey

“…Some AESs have substantially benefitted target species (e.g. Aebischer et al 2000, Peach et al 2001, Albrecht et al 2007, Perkins et al 2011 while others have shown no demonstrable benefit to target species or overall biodiversity (e.g. Kleijn et al 2001, Kleijn et al 2004, Davey et al 2010).…”

“…Recent work suggested that adaptive management, or 'learning through doing' (Convention on Biological Diversity 2004), is a key tool to improve the biodiversity benefits from AESs (Perkins et al 2011) by encouraging modification of AESs to improve their benefit for wildlife as new information comes to light.…”