MAIN RESULTS OF CLASSIFICATION OF SUMMER BIRD POPULATION OF THE NORTH EURASIAN PLAINS (ON THE MATERIALS OF DATA BANK OF THE COLLECTIVE USE)

E.S. Ravkin*¹, YU.S. Ravkin², L.G. Vartapetov², K.V. Toropov², S. M. Tzybulin² and V.S. Zhukov²

1. Center of ecologic-geographic developments SIA “Radon”, Moscow, 127562, Russia, ravkin_e@mtu-net.ru;

2. Laboratory of zoological monitoring Institute of Animal Systematics and Ecology Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630091, Russia, zm@eco.nsc.ru;

*To whom correspondence should be addressed. Russia, 127562 Moscow, Altufievskoye Road 30-229

Key words: East-European and West-Siberian Plains, zoogeography, classification, bird population, ornithocomplex, bird community, population density, biodiversity, zone, subzone.

Resume

Generalized classification of summer bird population of the East-European and West-Siberian plains is performed. In case of the unified approach the comparison of the classification data with that obtained earlier separately for the East-European and West-Siberian Plains has shown the higher level of conceptual generalization in ornithocomplex types. All classifications distinguished three typological-different systems of the terrestrial bird communities: natural and field communities, town, settlement, dump and ruderal ornithocomplexes and water –water –associated systems . Each system in all types of analyses distinguished northern and middle supra- type groupings , which boundaries are not coincident within each plains. With the increased climate continentality the northern (hypoarctic) bird populations , moving from the west to the east on each plains penetrate far to the south not only due to the vegetation changes, but shifting the ornithocomplex boundaries to the south relative to geobotanic and landscape borders.

Introduction

Till recently the descriptions and the analysis of bird community within the paradigm of factor zoogeography were applied to separate individual natural areas, provinces, subzones and zones. The accumulation of these data resulted in publications, generalizing them at the level of physic-geographic countries. Data on the East-European and West-Siberian plains have been recently compared. In this work the classification of ornithocomplex was first performed on the two plains. The increased volume of the analyzed data previously resulted in the completing of classification concepts. In the given case their unification resulted in great conceptual changes on the ornithocomplex heterogeneity.

Materials and methods

For the classification of the bird population of the East-European and West-Siberian plains data, accumulated in data bank of the laboratory of ecological monitoring, IS&EA SB RAS, have been used. Except for the authors' materials, we used data of literature references (about 70) and data of other contributors of data bank, kindly suggesting their materials for generalization. All participants and studied areas are given in our previous publications (Ravkin et al., 1994, 2001). Birds were censused in the first half of summer (from May, 16 till July, 15) in 1880-1907,1936-38,1947-97, with most of data being collected from the end of the 1970^th.

The censused routes cover the main bird habitats of all natural zones of the East-European plain as well as of the plain part of Russian Fennoscandia and the West-Siberian plain within the territory of the former USSR. According to our physic-geographical subdivision (Atlas of the USSR,1983), the East-European plain doesn't include semi-deserts and deserts of the Pricaspian lowland. Totally 2649 variants of ornithocomplexes were used for estimation. Variants were averaged on the legend's plots of the map "Vegetation of the European part of the USSR and Caucasus (1987) and West-Siberian plain (1976), scaled 1:2000000 and 1:1500000. Following these averaging, the data obtained have been arranged in 536 groups, between which the Zhaccar similarity coefficients were estimated to get the quantitative indices (Naumov, 1964). These coefficients were used for factor classification with subsequent subdivision of large classes, amounting five, and more average classes. Species classification was made with one of methods of cluster analysis (Trofimov, Ravkin , 1980). Therein to develop the conceptual classification schemes we limited the divisions under consideration with that, easily interpreted and understandable in view of studied subject. The detailed methodological and methodical bases of investigations are published earlier (Ravkin, Lukjanova,1976; Ravkin et al., 1994). Names of birds are given after A.I. Ivanov (1976), types of fauna – after B.K. Shtegman (1938) with some changes and additions.

Results and discussion

The comparison of the classification data, made separately for the East-European and West-Siberian plains and for their territory as a whole shows that in all three cases we distinguished by three typologically different systems of population. These are natural and field communities of the land, town, settlement and dump ornithocomplexes and ruderal and water and water-adjacent systems. Zonal changes in these systems are traced in all variants of analysis. Therewith, northern and middle supra-type groupings are distinguished. Boundaries of groupings in each plain don't coincide with the landscape and geobotanic division.

In natural and field communities of West Siberia the boundary of northern supra-type grouping lies between northern and middle taiga. It is not so pronounced in Europe, where it lies greatly northwards and the tundra population penetrates southwards to the forest tundra only on bogs and tundra landscapes and even to the south – only on palsa bogs till the band of northern taiga light forests In Siberia hypoarctic species penetrate to the south into northern taiga on vast bogs, flood- plains and light forests. In East Europe it occurs only on open habitats due to the relatively dense forests as compared with the Siberian ones. Thus, in the two plains, when birds fly from the west to the east, the boundary between northern and middle groupings of bird population shifts to the south, since with the increased climate continentality the northern (hypoarctic) bird population penetrates more to the south not only due to the vegetation change, but shifting southwards the boundaries of ornithocomplexes relative to geobotanic and landscape borders.

The bird community of middle supra-type grouping in Europe and Siberia involves by 6 types each. But number for number of types, the great differences in their volume are observed. In generalized classification only three types are distinguished – forest, raised bogs and meadow-steppe, i.e. high level of generalizion in the concepts on types of ornithocomplexes is traced. In East Europe the forest population represents two type: a) boreal; b) steppe forests and felled areas, in West Siberia only one – the forest type. The boreal (European) type is divided into three subtypes – forest-tundra-northern-taiga, forest and forest-meadow-field. In Siberia the population, similar to the first of them, forms and independent forest tundra type of the community, and the rest, like in Europe, is presented by the community of steppe forests and other variants of forest communities from the middle taiga till the forest steppe. Thus, in both cases subtype differences are due to the zonation and afforestation, but their bounds don't coincide with the division into zones and subzones. In Europe the forest subtype division is coincident with differences in the forest-forming species composition and in Siberia even to a greater extend with subzones' belonging and the degree of afforestation. As a whole for both plains the division into subtypes coincides with subzonal-regional differences and afforestation, and division into classes is characterized by more fragmental subzonal differences and only the lowest taxa are classified in association with the dominated forest-forming species composition. Boundaries of high bog type communities in Europe extend to a subzone to the north, than in Siberia, i.e. this type also includes the communities of the north-taiga bogs. By and large for the plains the southern boundary of the distribution of this type lies a subzone more southernly than separately in each plain, involving ornithocomplexes of the forest-steppe riams.

Marsh and meadow-steppe groupings when classified separately for each plains are distinguished into independent types. In generalized classification the meadow-steppe type of the community combines ornithocomplexes of all open productive habitats, i.e. without high bogs and northern communities beginning with the northern taiga communities.

The results of cluster and factor analysis are known to depend considerably on sampling volume. In this occasion our previous works have repeatedly pointed to the working character of all regional, provincial and zonal-subzonal classifications of ornithocomplexes, belonging only to the territory at issue. Therewith the type of the community was determined by conceptual notion on groups of variants, distinguished during the first (the most common and informative) division. The addition of samples didn't caused transformations in names and volumes of types. Everything remained within the earlier existed concepts, i.e. didn't result in radical changes of names and taxa bounds of type rank.

The combination of two considerable groups of data on the East-European and West-Siberian plains greatly transformed our notions. The higher level of generalization, based the unified classification, is caused by the appearance of transitional variants in a single sample, combining previously highly different subsamples. Great changes are also revealed for the northern part of the two plains. Types, that according to the European data were considered as the tundra type of bird community, are combined with Siberian forest-tundra and southern part of Siberian tundra types and represents a single forest tundra type of ornithocomplexes. The tundra type of the unified classification remains only the northern part of Siberian tundra type of the community . Thus, the great changes occur as in boundaries, so in the composition and, thus, in notions on types of the community of northern supra-type grouping at different territorial variants of classification.

Despite the conditionality of the distinguished boundaries and volumes of the community types, the unified classification shows one very interesting property. Geobotanic and landscape maps of Europe and West Siberia clearly shows (it was also repeatedly shown previously), that towards the west boundaries of zones and subzones greatly shift to the north due to the worming effect of the Atlantic stream. Accordingly, boundaries of ornithocomplexes are also shifted. In East Europe and West Siberia according to the regional classification the southern boundary of the tundra type almost unambiguously lies between the northern and southern (shrubby) tundra. In East Europe (except for the Extreme North-East) this boundary shifts practically to the coasts of the North Ocean. The community of small interior arctic and common subarctic tundras of Europe is not studied, thus, its type belonging remains unclear. Investigations, basing this work were partly financed by Russian Foundation of Basic Research.

The studies were financed by the Russian Foundation for Basic Research.

References

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