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Providing evidence to improve practice

Individual study: Amount of land designated as Ecological Compensation Area does not affect population densities of 37 bird species

Published source details

Birrer S., Spiess M., Herzog F., Jenny M., Kohli L. & Lugrin B. (2007) The Swiss agri-environment scheme promotes farmland birds: but only moderately. Journal of Ornithology, 148, 295-303


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Increase the proportion of natural/semi-natural vegetation in the farmed landscape Bird Conservation

A 2007 site comparison study of 23 sites in the lowlands north of the Alps, Switzerland (Birrer 2007), found that the percentage of farmland designated as an  ecological compensated area had no effect on the population density of farmland bird species or bird species with territories incorporating several habitat types. Ecological compensated areas are areas managed for the primary function of providing plant and animal habitat – these include meadows farmed at a low intensity. For 37 species surveyed in 1998/1999 and again in 2003/2004, population densities in wetlands and rivers were not affected by proxmity to ecological compensated areas, although hedges and traditional orchards close to ECAs did have higher bird population densities than those further away. Twenty-three out of one hundred hedges within ecological compensated areas had at least one of the 37 surveyed species present compared to 13 of 100 hedges outside the agri-environment scheme. The 23 selected sites (covering up to 3 km² each) were randomly selected and surveyed three times each between April and June in both years of study.

Increase the proportion of semi-natural habitat in the farmed landscape Farmland Conservation

A 2007 site comparison study of 23 sites in the lowlands north of the Alps, Switzerland (Birrer et al. 2007) found that the percentage of farmland designated as Ecological Compensation Area (ECA) had no effect on the population density of farmland bird species or bird species with territories incorporating several habitat types. ECAs are areas managed for the primary function of providing plant and animal habitat – these include meadows farmed at a low intensity. For 37 species surveyed in 1998-1999 and again in 2003-2004, population densities in wetlands and rivers were not affected by vicinity to ECAs, although hedges and traditional orchards close to ECAs did have higher bird population densities than those further away. The 23 selected sites (covering up to 3 km² each) were randomly selected and surveyed three times each between April and June in both years of study.

Manage hedgerows to benefit wildlife (includes no spray, gap-filling and laying) Farmland Conservation

A 2007 site comparison study on 23 sites in the lowlands north of the Alps, Switzerland (Birrer et al. 2007) found twenty-three out of one hundred hedges managed as Ecological Compensation Areas had at least one of the 37 surveyed bird species present, compared to 13/100 hedges outside the agri-environment scheme. The 23 sites (covering up to 3 km² each) were randomly selected and surveyed three times each between April and June in both years of study.