Low-intensity agriculture increases farmland bird abundances in France.
Farmland biodiversity continues to decline mainly because of agricultural intensification and land abandonment. Agri-environment schemes can be designed to halt this loss by favouring extensification of agricultural practices and through sympathetic management of field boundaries and fallow land. In Europe, High Nature Value (HNV) farmland is defined as low-intensity farmland supporting or associated with a high rate of biodiversity, in terms of species richness or habitat diversity and therefore plays a crucial role in the maintenance of European biodiversity. However, no large-scale analysis has explored the role of these areas in achieving conservation goals. We analysed information from widely used indicators in order to describe the impact of low-intensity agriculture on farmland biodiversity in France. We used the HNV farmland indicator, based on agricultural statistics such as the Farm Structure Survey and the grassland survey, and common bird indicators, i.e. the Farmland Bird Indicator (FBI), the Community Specialization Index (CSI) and species richness indexes, based on the French Breeding Bird Survey. Temporal trends in the farmland bird indicator showed that populations of farmland birds were more likely to increase inside HNV areas compared to non-HNV areas. Although species richness is not higher within HNV farmland, bird communities are composed by more specialist species than in non-HNV areas. In addition, these specialist bird species are significantly more abundant in HNV areas. Synthesis and applications. Further farmland biodiversity decline is potentially reversible through an appropriate management of HNV areas. Existing and future agri-environment schemes should focus on preserving and extending HNV farmland, by favouring the maintenance of low-intensity agriculture and landscape complexity. Priority should be given to preserving diversity at the community level, with the help of adequate indicators, such as the ones presented here. The role of HNV farmland or similar concepts in combining agriculture and biodiversity goals should be further analysed and further used as large-scale conservation tools.