The birds of Pasvik / E. I. Khlebosolov, O. A. Makarova, O. A. Khlebosolova [et al. ; English transl. Nikita Chernetsov]. - Ryazan : Golosgubernii, 2007. - 175 с. : ил., портр.

groups o f species between which the most close relationships exist in natural com ­ munities, and lumping them in the groups o f higher rank make it possible to deter­ mine the so-called functional structure o f community and to understand the m ech­ anisms o f its functioning as a holistic biological system (Khlebosolov et al. 2006b). In synecology such groups are commonly called guilds. Within guilds, the closest relationships between different species o f organisms exist. Biocenotic relationships between species of different guilds are much weaker and are indirect. Within-guild relationships between the species are most interesting for studying community structure (Root 1967). The functional role o f birds in communities is governed by their ecological niche. Therefore the ecological niche may be treated as an elementary unit o f func­ tional classification of communities. In the current synecological studies foraging behaviour is treated as the integral parameter that characterizes the ecological niche o f a species as a functional unit. Foraging behaviour is an elementary unit of ecological classification and makes it possible to identify functional groups, or guilds, o f different hierarchical rank on the basis o f similarity in foraging behaviour. The degree o f similarity (or dissimilarity) depends on diet, foraging sites and forag­ ing techniques. By consistent identification of different behavioural components from its structure and content one can determ ine the degree o f functional sim ilari­ ty o f different species and thus construct a hierarchical ecological classification of avian communities (Khlebosolov et al. 2006b). Ecological classification is in fact a hierarchical system o f species’ ecological niches grouped into categories according to the degree o f their similarity. Analysis o f trophic relationships ofb ird s suggests that functional and ecological subdivisions o fbirds o f different hierarchical rank generally agree with systematic taxa. It is nec­ essary to determ ine which ecological and functional characteristics are typical o f a certain taxon. A comparative analysis o f functional and ecological and taxonomic groups o fb ird s shows that different trophic factors (foraging tactics, foraging strat­ egy, food type in a given environment) that permit to group birds into ecological categories o f different rank correspond to taxonom ic categories, i.e. species, fam i­ ly, order (Khlebosolov 1999, 2004, 2005). Bird communities of Pasvik include several large ecological groups, or guilds, ofbirds: (1) waterfowl; (2) raptors and owls; (3) grouse; (4) shorebirds and gulls; (5) passerines (Fig. 2.2). In order to perform a detailed analysis o f biocenotic relationships w ithin an ecological group o fb ird s, it is necessary to know exactly the structure o f the e co ­ logical niche o f species that form this group. Such data are only available for com ­ mon species o f passerines. Within this guild we identify several smaller ecological 77