Effect of ecological compensation areas on floristic and breeding bird diversity in Swiss agricultural landscapes

In the 1990s the Swiss agricultural policy was reformed and new environmental objectives were formulated. The aims of the reform were to halt the loss of agro-biodiversity and to enable the spread of endangered species. As a result, the utilised agricultural area (UAA) is now interspersed with low input ecological compensation areas (ECA), making up 13% of the UAA (extensified grassland 90,000 ha, traditional orchards 25,000 ha, hedgerows 3000 ha, other elements 23,000 ha). To assess whether ECA contribute to the enhancement of biodiversity, plant composition was recorded on 1914 ECA of the Swiss plateau and 1966 territories of 27 bird species, which typically breed in open and semi-open farmland, were mapped and related to ECA. Eighty-six percent of ECA litter meadows and 50% of ECA hedgerows were of good ecological quality and attracted wetland and hedgerow birds. Most ECA hay meadows and traditional orchards, on the other hand, still reflected their former intensive management with only 20 and 12%, respectively, being of good ecological quality. Hardly any benefits for grassland and orchard birds were observed. Ecological quality of ECA was generally higher in the bio-geographical region ‘Basin of Lake Geneva and Upper Rhine Valley’ than in the other two regions of the Swiss plateau and it was higher in the agricultural production zone ‘Pre-alpine Hills’ than in the ‘Lowland Zone’.