Bird diversity relates to agri-environment schemes at local and landscape level in intensive farmland

Abstract

In Europe, more than 20 billion Euros have been paid to farmers for agri-environment schemes (AESs) during the last half decade to counteract negative effects of farming on the environment. In Sweden alone 0.4 billion Euros are paid to farmers for AESs every year, but large-scale analyses of the relationship between AESs and biodiversity are scarce in northern Europe. We surveyed farmland birds at over 600 sites in non-crop habitats in 37 arable dominated landscapes (each 25km2) in southern Sweden and investigated if bird species richness and abundance were related to the amount of agricultural land receiving subsidies for five common AESs. Abundance and species richness of three subsets of farmland birds were positively associated with AES for management of permanent pastures, and bird abundance was associated to habitat elements managed for the maintenance of nature and cultural values (e.g. old buildings, infield non-crop islands, stone walls and ditches). Farmland bird abundance was also positively associated with the amount of grasslands (leys and especially pastures) and set-aside without subsidies, whereas neither richness nor abundance was positively associated with the amount of organic fields at the local scale (i.e. within a 250m radius). However, bird diversity was related to increased area of organic fields at the landscape scale (i.e. 25km2); with a positive relationship in the most simplified landscapes but a negative relationship in more complex landscapes (i.e. with less arable land and more woodlands). Our results show that AESs are targeting habitats and habitat elements of high farmland bird diversity with the possible exception of organic farming in less simplified landscapes. Future studies investigating effects of AES management need to collect longitudinal before–after data on the change of biodiversity and need to investigate the possible landscape-dependent outcomes of specific management tied to AESs.