Scientific publications

The last large-scope ornithological survey in the Kostomukshsky Strict Nature Reserve was conducted some 20 years ago by S. V. Sazonov. Inventory and diversity assessment of the avifauna in the then-planned national park Kalevalsky were also conducted by S. V. Sazonov in 1992 and 1995-1997. In 1997 he was joined by N. V. Medvedev, Y T. Khokhlova, N. V. Lapshin, and A. V. Artemyev. The findings from these surveys were published later. To investigate the current state of the avifauna and assess possible changes during past decades special surveys were conducted in the reserve in June 2015 and July 2016. The method consisted in a combination of transect surveys, partially duplicating the routes surveyed in the previous years, and examination of sample plots representing all the main types of local habitats. Overall, the surveys covered around 20 % of the nature reserve area, including the Kalevalsky National Park (now incorporated within the strict nature reserve). A part of the routes included lake sections (specialized waterfowl surveys). Several plots were established in the reserve's buffer zone and in the suburbs of the Town of Kostomuksha (territory under the reserve's authority). Current records from the surveyed area include 105 species of birds belonging to 33 families of 13 orders. It should be noted, that the list of species in our paper is shorter than the one compiled after the longer surveys conducted 20 years ago (in Sazonov's publication of 1997). First, the new list misses some rare and vagrant species, the registration of which is largely random in nature and is more likely during long-term studies. In addition, for some species the optimal time of observation when birds are more noticeable is spring (migration and active demonstrations), and not summer, when our investigations were conducted. A small share of species in the reserve is more common in winter. Thus, to obtain up-to-date data on birds of these categories and, in general, to provide a more complete analysis of the state of the avifauna in the reserve, further monitoring studies are needed in all existing types of landscapes and habitats in different seasons of a year. However, a slight increase in the species diversity was observed in data from our transects compared to the results of previous studies. The reasons for that may be associated with the redistribution of birds across the reserve, some successional changes, specifics of the seasons of 2015 and 2016, and natural population dynamics of different species. In general, according to data pooled from all the surveyed sites, we can conclude that the qualitative status of the avifauna in the reserve (species presence) has changed insignificantly over the past two decades, which is apparently due to the fact that most of the local habitats are in final stages of the succession, with communities close to climax. At the same time, some changes in the quantitative composition of the avifauna were noted: the share of typical boreal species has declined, whereas the proportion of species with wide distribution and species typical of southerner regions slightly increased. The reasons for these changes are not completely clear, but because such a situation has been observed in other boreal complexes as well, we can assume that this is an expression of global processes, of the natural population dynamics of species.