The number of little owls, Athene noctua is decreasing in many European countries. In order to evaluate causes of the decline in Poland, habitat preferences of this species were analysed. Using GIS methods, 25 settled territories of the little owl, recorded during field surveys between 2000 and 2005, were compared with 50 unsettled locations. It was found that the proportion of built-up areas was higher in the occupied territories than in the random locations. No differences in grassland, forest and field proportion, habitat diversity and edge length were recorded between the occupied, and the random locations. The amount of forest and the proportion of built up areas appeared to be the best predictor of the occurrence of the little owl. Next, habitat use at 7 additional territories, which were occupied by little owls in 1980–90s and later abandoned, was analysed. In 2006, as compared to the period 1980–90, numbers of pollard willows decreased, whereas the number of buildings increased in these territories. The overall results lead to a conclusion that the little owl shows a high degree of habitat plasticity. The decrease of the area of grasslands and numbers of pollard willows is not likely to explain the population decline of the species.
Factors which have a negative impact on mammal populations were reviewed for all 83 native species occurring in Germany today. Forest management affects most species of the mammal fauna as well as of the sub-groups of Red List species and of species for which a special responsibility for their conservation has been determined in Germany. This is because a high proportion of German mammals are forest-dwelling, which means they are exposed to current harmful forestry practices such as selective harvest of ancient trees. The review also highlights population reduction by direct take of individuals (legal, illegal or accidental) and habitat fragmentation as major conservation problems affecting many species. The analysis of negative impact factors underline the importance of ongoing „traditional“ conservation measures. However, the result of climate change and invasive alien species being less important for conservation, as only few species are affected so far in Germany, is doubtful. The impacts of these two factors may be underestimated owing to a general lack of data. To ensure that conservation problems can be identified and appropriate measures are taken, the implementation of a mammal monitoring programme and specific research projects are needed. International cooperation might be helpful to overcome national shortcomings in mammal conservation in Germany and other European countries.