Regularities of altitudinal belt differentiation of the summer bird community in the Barguzin Nature Reserve

eserve The research presents the results of investigating the ecological regularities of altitudinal-belt differentiation of the bird population in the Barguzin reserve. Studying the formation of bird fauna and population in the conditions of altitudinal zoning, as well as the factors influencing it, is one of the promising research areas in the Baikal region. The results of such work carried out in undisturbed reference areas can serve as a basis for assessing the size and direction of the natural structure variability of bird communities. The Barguzin State Natural Biosphere Reserve is located in the Northeast Baikal region. It is the oldest Nature Reserve in Russia, created in 1916. Located in undisturbed natural systems, this reserve reflects best global environmental changes. We collected data during expeditions in the summer 2014 on the territory of the reserve within the western slope of the Barguzin Range. The studies were conducted at key sites of the reserve in 5 altitudes: riverside plain (460-520 m asl and higher), foothill (520-630 m asl and higher), forest (630-1200 m asl and higher), subalpine (1200-1400 m asl and higher) and alpine (1400-2800 m asl and higher) in the valleys of three rivers. Ornithological surveys were carried out in the first half of summer, which corresponds to the nesting population of birds. When carrying out the research, we used the method of route counting of birds without limitation of the counting strip width, followed by recalculation to the area in terms of the bird detection range by the interval method (Ravkin Yu.S., 1967). The total length of the routes was 221 km, including the permanent route along the Davsha river valley - 62 km, along the Ezovka river valley - 69 km and the Bolshaya river valley-90 km. We analyzed the bird