Abstract:

Across much of Europe, farmland birds have declined more than those in other habitats; many of the most threatened birds are dependent on extensive farming systems. This paper describes two case studies in which bird abundance was monitored in relation to spatial and temporal differences in agricultural management, one in southern Portugal, the other in central England. In Portugal, bird abundance and species diversity were monitored in 1995 using transects in relation to three agricultural systems. Bird abundance and species diversity were both low in simple intensively managed farmland, and highest in extensively managed farmland incorporating agroforestry systems (Montado). However, species of greatest national and European conservation concern were most abundant in simple, open, extensively managed landscapes. These extensive systems are therefore important for species diversity at national and European scales. In England, a conventionally managed farming system was adapted to encourage gamebirds for shooting, and bird abundance was monitored annually. Transects were conducted within the study area from 1992 to 1998 and additional transects were conducted randomly in the surrounding farmland from 1995 to 1997. Bird abundance increased during the management period and was higher in the study area than in the surrounding area, especially for nationally declining species. However, there was little difference in species diversity across years or sites. Our monitoring demonstrates three important points: 1- Extensive farming systems play an important role in maintaining species diversity at national and European scales, even where abundance and diversity are low at the farm scale. 2- Abundance of nationally declining bird species can be restored rapidly, following population declines, if appropriate management systems are adopted. 3- Bird conservation can be accommodated within multifunctional land-use systems, including agricultural systems incorporating game management.