The diet composition and prey selection of grey wolves (Canis lupus) inhabiting the Roztocze and Solska Forest (south-east Poland) was studied based on an analysis of scats collected in 2001-2002 (n = 84) and 2017-2020 (n = 302). In both periods, wolves preyed mainly on wild ungulates (96.5-96.7% of consumed biomass). Roe deer (Capreolus capreolus) was the most critical wolf prey accounting for 57.8% of consumed biomass in 2001-2002 and 49.2% and 2017-2020, but wolves positively select only wild boar (Jacob's selectivity index D = 0.213 in 2001-2002 and 0.710 in 2017-2020) and fallow deer (D = 0.588 only in 2017-2020). The largest species – moose Alces alces and red deer Cervus elaphus – were consumed less than expected from their share in the ungulate community. Predation on medium-sized wild mammals and domestic animals was low, 0.8-2.2% and 1.1-2.7% of the biomass consumed, respectively. The breadth of the wolf diet was very narrow and identical in both study periods (B = 1.07), while the similarity of diet composition was high (α = 0.999). This study indicated the stability of the wolf diet over two decades and the importance of wild boar as a food source for this carnivore.
From September 1994 to August 1995 we studied the diet of coypus, Myocastor coypus, in a freshwater habitat located in the Ticino regional park (NW Italy). Adult and young coypus were directly observed foraging in and near water. Aquatic macrophytes (81.8%) represented the staple food all year round. Common reeds (Phragmites australis) and Elodea spp. were the main components of the overall diet. A complementary seasonal consumption of submersed/floating-leaved macrophytes and emergent macrophytes was observed, the former ones reaching the highest value in summer (65.7%) when the latter ones were at their minimum (16.2%). Differences in diet composition of adult and young coypus were recorded in summer, when adults consumed more submersed/floating-leaved plants (mainly Callitriche stagnalis and Myriophyllum spicatum) and young coypus more terrestrial plants, predominantly black locust Robinia pseudoacacia leaves. Terrestrial vegetation was a usual integrative resource of the coypu diet all year round, particularly for young coypus in summer. Slight damage to the plant community was observed in small areas over-grazed by coypus. Nevertheless, 7 out of 12 threatened Italian hygrophilic species were eaten by coypus, suggesting that particularly sensitive aquatic plants could suffer from long–term foraging. Selective control of coypus in natural ecosystems of particular conservation concern is suggested, in order to limit damage to native plant communities of freshwater habitats.