BIRD AND SMALL MAMMAL COMMUNITIES IN A CLEARING CAUSED BY AIR-POLLUTION

Twenty-seven bird and nine small mammal species were found within a cl earing of the Moravskoslezske Beskydy Mountains (Czech Republic) induc ed by air pollution. Of the breeding birds, meadow pipit Anthus praten sis showed the highest average density (117 pairs.km(-2)) and dominanc e (29.2%), whereas the values in other species ranged from 7 to 57 pai rs.km(-2) and 1.7 to 15.0% respectively. In small mammals, the highest average values were reached by field vole Microtus agrestis (2,346 in dividuals.km(-2) and 57%), whereas the density and dominance of other species ranged from 100 to 1,138 individuals.km(-2) and 0.2 to 26%, re spectively. The total average density of breeding bird community reach ed 400 pairs.km(-2), that of small mammal community 4,231 individuals. km(-2). Clearings following clear-cutting dead or dying forest stands created entirely new ecological conditions for birds. All tree layer o r canopy-dwelling species were absent there, and, on the other hand, f ive open area dwellers colonized this habitat. The total average densi ty of breeding bird community per km(2) was markedly lower compared to the bird community of an old forest stand located 1 km southwards. As for small mammals, clearcutting only slightly reflected in the specie s composition, whereas the population density and dominance of both in dividual species and the whole community changed markedly.