Êîíñïåêò
ABSTRACT. Analysis of a species’ distribution pattern in the marginal part of its geographic range is usually performed on a qualitative level. At the same time, quantitative estimation of area of occupancy could be of great importance for distinguishing the sites inhabited by the species from those where it is “occasionally” found. For large mammals in areas of current or recent expansion an analysis of the distribution patterns is especially complicated by high mobility of the animals, lack of data about habitat preferences and, consequently, the impossibility of using the assumptions of “closed-population models” for estimating area of occupancy. In this study we report a retrospective quantitative analysis of wild boar distribution in one of the areas of European Northeast Russia based on records of occasional detections for the period 1984–1999. Indices of “minimum site occupancy” and “constancy of species’ presence” (the proportion of years, when the species has been recorded within the study area) were used for estimation of species “extent of presence” for the whole study area and distinct parts of it. The wild boar is “vagrant” or not present in most areas situated close to the Ural Mountains. In the plains areas, the species has at least “visitor” status. Thus, only about 50% of the study area could be treated as part of wild boar geographic range. The quantitative method developed allows estimation of the species’ status within a study area and avoids biases in analysis of resource selection by excluding the territories where it is “occasional” or “vagrant”.
KEY WORDS: wild boar, taiga, distribution, site occupancy, constancy of presence.
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