Martsiv M. Diet of predatory mammals in the anthropogenically transformed environment of Western Ukraine.

The dissertation is devoted to the study of the nutritional characteristics of 11 species of carnivorous mammals in the conditions of the anthropogenically transformed natural environment of western Ukraine. An analysis of feeding spectra of stone and pine martens, weasel, stoat, river otter, and red fox was carried out; the peculiarities of trophic relationships and trophic competition of predators are clarified; factors influencing the trophic behavior of predators are determined; an analysis of the changes that occurred in the trophic of these species in the territory of western Ukraine over the past half-century was carried out; the changes in the diets of predators depending on the geographical distribution were clarified and the modern importance of predatory mammals in the anthropogenically transformed environment was established. During the research, data were collected on the diet of 11 species of predators: red fox, wolf, common raccoon dog, river otter, pine marten, stone marten, weasel, stoat, European badger, European polecat, and American mink. A total of 379 food samples of carnivorous mammals of two families: Canidae and marten Mustelidae were analyzed. It was established that the diet of predators in the western regions of Ukraine includes 93 food items, both of plant (32 items) and animal (61) origin. The results of non-metric multidimensional scaling of sample data showed that three parameters (with a correlation of 0.21) best describe the similarity of samples: collection method, predator species, and settlement areas. Data analysis showed a significant difference in the diet of the river otter from the diet of other species. Considering the obtained model, it can be concluded that the trophic niche of this predator slightly overlaps with the weasel, stoat, pine marten, and fox. Trophic competition is most pronounced between the red fox and pine martens (Sørensen's index is 70 %) and stone martens (Sørensen's index is 61 %). The similarity of the diet of two species of martens according to the Sørensen index is 63 %, and that of the stoat and weasel is 58 %. The diet of the otter is significantly different from the diet of other predators, so it almost does not compete for resources with other studied species. With the help of regression analysis of the sample data, the factors that can affect the consumption of five types of feed by predators have been determined. In particular, the probability of consuming juicy fruits depends on the type of predator: statistically lower chances of finding the remains of these foods in food samples of river otter (β = -6.5, Q: -11.8 / -3.2), stoat (β = -5 ,4, Q: -11.8 / -1.2) and weasels (β = -3.2, Q: -5.9 / -1.1) than in fox samples. In addition, the season has a negative effect on all types of predators, reducing the chances of consuming juicy fruits in spring (β = -2.9, Q: -4.5 / -1.5), winter (β = -1.9, Q: -2.9 / -0.9) and summer periods (β = -1.1, Q: -4.5 / -1.5). The type of predator is a statistically significant factor affecting the consumption of the category of other plants and reduces the chances of finding this type of food in the diets of otter (β = -2.5, Q: -3.6 / -1.6), weasel (β = -2, 9, Q: -4.1 / -1.7), stoat (β = -2.1, Q: -3.6 / -0.5), stone marten (β = -1.4, Q: -2.6 / -0.2), American mink (β = -3.9, Q: -6.9 / -1.1) and European polecat compared (β = -2.9, Q: -6 .1 / -0.4) with red fox. Invertebrate consumption is influenced by all factors of the logistic regression model. In particular, the probability of detecting invertebrates in the food samples of the marten strongly increases (β = 1.7, Q: 0.9 / 2.5) compared to the fox, but the probability of consumption of this food by the otter, on the contrary, decreases (β = -1, 3, Q: -2.4 / -0.4). According to the results of the regression analysis, the winter period reduces the chances of predators to hunt invertebrates (β = -2.4, Q: -3.7 / -1.2), and the summer period increases the probability of consuming these foods (β = 0.8, Q: 0.1 / 1.7). The area where the data were collected also affects the probability of invertebrate occurrence: animals living or feeding in populated areas are less likely to consume invertebrates (β = -1.3, Q: -2.6 / -0.1). The probability of detecting lower vertebrates in food samples is statistically higher for otter (β = 6.9, Q: 5.1 / 9.2). Neither the season nor the area of material collection has a significant effect on the consumption of these food items. The type of predator and the season statistically significantly affect the consumption of rodents. For otter (β = -4.1, Q: -6.7 / -2.2) and pine marten (β = -0.9, Q: -1.7 / -0.1), this factor is negative, which reduces the chances of finding rodents in food samples of these species. Spring (β = 1.1, Q: 0.2 / 2.0) and winter (β = 1.0, Q: 0.2 / 1.9) seasons have a positive effect on rodent consumption — increasing the chances of rodent detection in predator samples.