Modelling farming system dynamics in High Nature Value Farmland under policy change

•Farming systems in 40% of the area changed during 10 years.•Major transitions were from arable to either livestock or permanent crop systems.•The traditional system declined despite support from agri-environment schemes.•Agricultural intensity did not change but land use heterogeneity strongly declined.•Results suggest negative impacts on biodiversity.

Understanding the factors driving changes in farm management is needed for designing policies and subsidy schemes to protect High Nature Value Farmland (HNVF). We describe farming system dynamics in HNVF of southern Portugal, between 2000–2002 and 2008–2010, encompassing a period of major policy transformations introduced by the reform of the Common Agricultural Policy (CAP) of the European Union in 2003. We also assess how farming system dynamics was modulated by structural, biophysical and policy factors constraining agricultural options. Farming systems changed in about 40% of the farmed area during the period of study. Overall, there was a marked transition from arable systems to either specialized livestock or permanent crop systems, involving major declines in the traditional system of dry cereal rotations and sheep grazing. Transitions were influenced by farm size, soil quality and coverage by open oak woodlands, while there was little effect of agri-environment schemes and legal regulations specifically targeted to support the traditional farming system. Despite these changes, agricultural intensity remained essentially stable, though there was a marked decline in land-use heterogeneity with likely negative impacts on biodiversity. Observed changes agree with ex-ante impact assessments of the CAP reform in Iberian cereal steppes, which suggested that decoupling of payments from production could promote shifts from the traditional cereal–fallow–sheep system towards specialized livestock grazing systems. Effectively protecting HNFV may thus require a better integration of horizontal policies and agri-environment schemes.