Similarities and differences in floodplain bird communities of the Urals and the Amur basin on the example of three nature reserves

The paper deals with the comparison of bird communities in the rivers floodplains of Vishera (Northern Urals, reserve "Vishersky"), Selemdzha and Nora (Amur region, reserve "Norsky") and Gorin (Khabarovsk region, reserve "Komsomolsky"). A fairly high similarity in the species composition between the Urals and the Amur basin (Is 0.48 and 0.46) as well as a low overlap in abundance (Isc 0.19 and 0.14) were revealed. The proportion of the representatives of passerine birds in the nature reserves was comparable: 74.6% on the river Vishera, 78.0% and 77.8% on the rivers Selemdzha and Gorin, respectedly. Differences between regions, according to the results of factor analysis, were manifested in the high significance of some taxa. At that, the representatives of Fringillidae Silvidae and Charadriiformes have a high significance in the Urals, while in Amur region those of Emberizidae, Muscicapidae, Paridae and Piciformes are highly significant. The structural diversity of the communities is primarily determined by the regional differences in latitude. Latitudinal differences of the studied regions are clearly manifested in the values of diversity indexes: in the Northern reserve "Vishersky" they are the smallest, whereas in the southern reserve "Komsomolsky" they are the greatest. The meridional differences between ornithocomplexes are manifested in the species composition of the communities, at that among the semiaquatic birds this difference is minimal.