Winter abundance trends of land birds in European Russia: an analysis of long term study data with TRIM software

Preobrazhenskaya, E.S.; Morkovin, A.A.

Авторы: Preobrazhenskaya E.S., Morkovin A.A.
Сборник: Rabaça J.E., Roque I., Godinho C. (Eds.). Bird Numbers 2019: counting birds counts. Book of Abstracts of 21st Conference of the European Bird Census Council
Тезисы
Год издания: 2019
Место издания: University of Évora Évora
Первая страница: 165
Последняя страница: 165
Аннотация: Since early 1980-s, “Parus” program coordinates winter land bird census on an extensive network of study sites across the European part of Russia. The territory of about 3.3 million km2 was divided into longitudinal sectors of 5 forest subzones (2–4 sectors in each subzone). Volunteer observers conduct long-term annual censuses on 25 study sites. On every site, censuses are made on at least 20-km route for one or more dominant forest types. We analyzed winter abundance trends for 17 most abundant species over the period 1987–2018. Using rtrim package for R 2.0.6, we estimated missing data for all study sites. For each sector, we averaged winter population numbers, considering the area of forest habitats appropriate for each species. These assessments, divided by number of study sites in each sector, were used as weight coefficients in trends calculations. We obtained population indices and calculated trend parameters for the whole study period, as well as its first and second parts (before and after 2002). Using MSI tool for R, we calculated multispecies index (MSI) for 16 wintering species (all studied species except Common Crossbill). None of the species had positive trends in any period. During 32 years, 5 species showed stable trends, and 8 of them demonstrated significant population decline, in many cases accelerated since early 2000-s. The decline was most pronounced in Willow Tit (Poecile montanus), Great Tit (Parus major), Goldcrest (Regulus regulus) and Eurasian Nuthatch (Sitta europaea). The resulted MSI also showed a moderate decrease (-1.5% / year). The causes of such tendencies remain unclear, but for most of the studied species, they probably reflected the changes in tree composition, caused by intense logging in the taiga zone. It had resulted in a dramatic decrease of old coniferous forests area, which was substituted with young, mostly deciduous stands. Other factors such as climate change might also play a role.
Добавил в систему: Морковин Антон Алексеевич

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Winter abundance trends of land birds in European Russia: an analysis of long term study data with TRIM softwareтезисы доклада Тезисы

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