Changes in a Bird Community in an Agricultural Landscape in Northeast Germany between 1999 and 2015

Temporal changes in the bird community of an agricultural landscape in northeast Germany were analysed covering three different analytical foci (landscape-wide, habitat types, sample plots) and two aggregation levels of bird observation data (whole bird community, bird guilds). The analyses are based on a systematic data sampling over two multi-year campaigns (1999-2002; 2013-2015). Our analyses address the question of how changes in the occurrences of agricultural birds (numbers of species and of individuals) at local spots manifest themselves in the landscape as a whole. By summarizing all findings concerning single variables (number of species, observation frequencies, abundances, different habitat types, bird guilds), a dramatic, systematic decline of the bird community at sample plots was discovered between the campaigns, which is not yet recognisable across the whole landscape in terms of species richness. Furthermore, we found that landscape-wide, the birds' use of habitat changed; the variability between single sample plots increased strongly and most species occurred at fewer sample plots over the whole landscape. Obviously, sample plots with high bird occurrences are becoming more relevant for maintaining bird communities over the whole landscape. Bird community composition changed significantly within the observation period.