The dissertation is based on findings of color forms collected on the basis of own research (2004-2018), questionnaires (2004-2007), work with observation cards (2009-2014), the database of the statistical bulletin (1999-2007) on the management of hunting in Ukraine (form “2 TP Hunting”), as well as museum collections during 2004-2017. Due to the high color variability of the Red squirrel, the study of this species was conducted in two directions: biological and ecological. The study of biology is considered from three aspects, namely: nutrition, physical activity, and species settlements. The study of environmental aspects consisted of explaining the particular ecological patterns of the existence of color forms of Red squirrel, where a complex use of methods was necessary. The material was collected during in-station site surveys in different areas of the region through direct observations. Mathematical and statistical methods were used to process the data. As a result of the conducted researches, it was possible to establish the following: three colored forms of squirrel (black, brown, red) are distributed on the South-western macro-slope of the Ukrainian Carpathians. In general, there are four color forms in Ukraine: black, brown, red and orange. In urban landscapes of the Transcarpathian region, the squirrel is more numerous than in natural locations. The reason for increasing diversity in the commensal environment may be the weakening of selection due to the favorable conditions for different forms (mixed forests – brown and red form, coniferous forests – black; a city where heterogeneous vegetation – two forms). The low number of predators – the lack of directed selection – allows maintaining a high level of variability. In the anthropogenic settlements of the Southwestern Macro-slope of the Ukrainian Carpathians, several color forms coexist, which obviously reflects their ability to adapt to the relevant environmental conditions. In natural settlements, colored forms are usually spatially separated.
Overall, brown in color is quantitatively prevalent in the study area. In Ukraine, black and brown forms of squirrel are widespread at altitudes of 200 to 1000 m above sea level. The red color form occupies heights from 100 to 500 m in both natural and anthropogenic zone. Red-form of squirrel meets at altitudes up to 200 meters above sea level, mainly in the anthropogenic zone. This color pattern extends beyond the Carpathian region only. The color squirrel polymorphism common in the region is an adaptation of the species to the specific conditions of the region. Dark-colored squirrels (black and brown forms) are most adapted to the mountainous conditions of the region, its natural moisture conditions and forest conditions. For light-colored forms (red in western Ukraine and orange outside the Carpathian region), foothills and flat conditions are optimal for existence. The conducted researches allow us to create and implement a database on the distribution of different colored forms of the squirrel on protected sites of the region in order to constantly account for different populations of squirrel and to ensure their gene pool. In order to preserve the heterogeneity of the population, squirrels in the studied region should be available both natural and anthropogenic habitats characteristic of a squirrel's of different color forms, which is best realized in the econetwork system, since the latter includes anthropogenic settlements in natural locations.
