© Marcel Burkhardt
Zbinden, N., H. Schmid, M. Kéry & V. Keller (2005)
Swiss Bird Index SBI® - Kombinierte Indices für die Bestandsentwicklung von Artengruppen regelmässig brütender Vogelarten der Schweiz 1990-2004.
Ornithol. Beob. 102: 283–291
Birds can be good indicators of changes in the environment in relation to land use. Population trends of individual bird species are, however, only partly suitable for a general assessment, which is necessary, for instance, to measure progress in relation to conservation targets. Here, we present combined indices for different groups of bird species. Population trend indices for individual species, calculated from the results of different national monitoring schemes, formed the basis. Trend indices could be calculated back to 1990 for 169 of the 171 regular breeding species. Multi-species indicators were calculated as the geometric mean of species indices. Combined indices were calculated for all regular breeding species together and for different groups of species. The combined index for all regular breeders does not show any trend over the study period. The group of species on the Swiss Red List showed a clear negative trend, while near-threatened species showed a slight positive trend. No trend was found for species for which Switzerland hosts internationally important populations. Trends for habitat guilds show opposing tendencies: while forest birds showed a positive trend, the trend for farmland birds was clearly negative, reflecting the known difficulties of birds breeding in agricultural habitats. The negative trend for wetland species is mainly influenced by strong decreases of birds breeding in wet meadows and marshland. Long-distance migrants showed a decreasing trend, in contrast to resident species and short-distance migrants.
Keywords: indicators, population trend, birds, Switzerland.