Home – Home – Jornals – Contemporary Problems of Ecology 2020 number 6

In 2016 and 2017 from April to July the bird individual nesting home ranges were regularly mapped along the permanent census route (2.8 km) in the Altai low-mountain forest dominated by pine and birch. Based on the mapping results, for each bird species the nesting densities and average sizes of the bird individual nesting home range were estimated. Raster maps of spatial allocation (MSA) at the scale of the raster grid of 50 × 50 m were obtained for each species. The degree of spatial conservatism (DSC) for each local population was inferred from the pairwise comparisons of the specific MSAs obtained at the same area (28 hectares) in different years with the use of the Gamma rank correlation method. Dependence of the population habitat area on DSC was demonstrated earlier [Cherenkov, 2017]. The more habitat area is found, the less dependent the individual spatial allocation within a population is observed in the different years. Based on the specific habitat areas, average sizes of the individual nesting home range and nesting densities estimated, the maximum possible nesting density and habitat saturation are calculated for each species. The significant DSC estimates ( p < 0,05) were obtained for 15 species, their habitat areas and habitat saturation were found. The population status was inferred from the degree of habitat saturation. Average estimates of the degree of habitat saturation were close in migratory and non-migratory species (49 % and 45 %, respectively). The Altai birds wintering in Southeast Asia did not differ in the degree of habitat saturation from those wintering in Southern Europe and North Africa. A comparison of avifauna status of the Altai and Baikal regions revealed the substantial differences. Number of the most common migratory species nesting in Altai is almost twice higher than that nesting in the Baikal region. For these species, in Altai the average nesting density is four times higher and habitat saturation is twice higher than in the Baikal region. The latter difference evidences for the twice more intensive pressure of some factors limiting the population numbers of migratory species in the Baikal region compared to Altai. At the same time, there were no significant differences in ecological population status of the non-migratory species between these regions. Close estimates of the degree of habitat saturation in the non-migratory species in the Altai and Baikal regions support a suggestion that the integrate influence of factors limiting their population numbers is similar in both regions. Close estimates of the degree of habitat saturation and nesting density in the migratory and non-migratory Altai species show that neither of the two strategies of surviving gives a pronounced advantage. Difference between the Altai and Baikal regions in the degree of habitat saturation in the migratory species is seemingly determined by the different mortality levels in the wintering areas and on the routes of migrations.