Вивірка лісова (Sciurus vulgaris) в природних і антропогенних біотопах національного парку Подільські Товтри

Abstract

The red squirrel Sciurus vulgaris inhabits biotopes with different levels of anthropogenic influence. The aim of the work is to analyse the biotopic distribution and abundance of the red squirrel in natural (forests of various specific and age composition, shrubberies, and river valleys) and anthropogenic (settlements, forest strips, and orchards) habitats in the territory of the Podilskyi Tovtry National Nature Park. Research was conducted from 1990 to 2022 at monitoring sites (different types of forest, arboretum, canyon of the Smotrych River, separate areas of settlements) and in separate biotopes of the natural park. We used the method of transect survey to estimate the number of red squirrels calculated as the number of individuals per 1 ha, as well as description and mapping of nests, and photography. The red squirrel is a non-abundant species in forests of different specific composition and age, where it is most often found in coniferous (especially spruce) and mixed forests, as well as in mature forest types and in areas bordering settlements. Of the studied natural habitats the red squirrel has the lowest abundance in the shrubberies on the slopes of Tovtry and river valleys, as well as in locust areas of forests. In the valleys of the rivers outside of settlements, the red squirrel occurs rarely. Of the forest strips, the most attractive for the species are the roadside strips with Juglans regia plantations in many areas, while the least attractive are field protection strips. Population density in anthropogenic biotopes is much higher than in forested ones. The most attractive are the arboretum zone of the city, where the population density in some years reached 2.5 individuals/ha. Anthropogenic biotopes are attract the species with the availability of food (primarily the fruits of common and black walnuts, Juglans regia and Juglans nigra) and the reduction of pressure by the forest marten. In urban settlements, the red squirrel more often settles in nests (groves) compared to forest biotopes, which is connected with the limited number of hollows due to periodic sanitary felling in the arboretum and along highways. In the monitoring areas of the forest, fluctuations in the abundance of the species are observed depending on the availability of food, in particular spruce cones. In the last three years, a trend of a sharp decrease in the number of red squirrels in anthropogenic biotopes has been revealed.