Biodiversity conservation in agricultural landscapes
Ecology | Social Psychology | Social Sciences Interdisciplinary (Peace and Conflict Research and Studies on Sustainable Society)
Agricultural industrialization alters rural landscapes in Europe, causing large-scale and rapid loss of important biodiversity. The principal instruments to protect farmland biodiversity are various agri-environmental measures (AEMs) in the EU Common Agricultural Policy (CAP). However, growing awareness of shortcomings to CAP biodiversity integration prompts examination of causes and potential solutions. This thesis assesses the importance of structural heterogeneity of crop and non-crop habitats and evaluates some related aspects of the CAP for 2015-2020. This includes studies of crop diversification, organic farming and buffer strips, and their potential for supporting deteriorating farmland bird diversity in a forest-farmland gradient. It also evaluates the role of collaborative conservation, with particular attention to the Swedish Volunteer & Farmer Alliance (SVFA), as a tool for influencing farmers’ engagement in AEMs as well as unsubsidized conservation.
Structural crop diversity, rather than the number of crop types in itself, positively affected farmland birds, especially in arable-dominated landscapes. Still, as almost all farms already met the CAP requirements for crop diversification, this policy may miss an important opportunity to deliver biodiversity benefits by setting limits too low and by neglecting structural crop diversity. The establishment of buffer strips along ditches boosted Skylarks and invertebrate numbers in adjacent cereal fields, while organic farming had only small and mixed effects on farmland birds, with both positive and negative effects on field nesters in the most arable-dominated landscapes and more forest- dominated landscapes, respectively. In general, landscape composition had a major effect on species richness, with different habitat preferences among field-nesting and non-crop-nesting birds. Social factors were more important for farmers’ engagement in AEMs than for unsubsidized conservation, suggesting that production-impeding AEMs may have poor chances of acceptance in regions with prevailing productivist norms. We also found that SVFA promoted both AEMs and unsubsidized conservation, and that measures positively affected farmland bird diversity in the most arable- dominated landscapes. However, low implementation rates of measures across SVFA limited the large- scale impact, highlighting the importance of following up stakeholders’ involvement.
This thesis suggests that farmland biodiversity conservation partly relies on policies that increase the structural heterogeneity of arable landscapes (e.g., through crop diversification and establishment of buffer strips). This is especially important in regions where arable farming is predominant and farmland heterogeneity is low. We conclude the future of AEMs for biodiversity protection partly lies in better integration into cultures of farming communities, possibly through volunteer-based approaches as an alternative to centralized solutions.