The role of islands in maintaining the connectivity of habitat for mammals in middle Vistula river valley

Live trapping and tracking was used to evaluate mammalian species richness, and habitat modelling to assess the connectivity of habitats for three rodent species in the 90 km long fragment of the Vistula valley, one of the few large European rivers preserved in semi-natural state. Our results revealed the differences between local population dynamics of Bank vole Myodes glareolus, Yellow-necked mouse Apodemus flavicollis and Striped field mouse Apodemus agrarius on the island and the bank. The LARCH model outputs indicated the potential for large viable populations of these species in the study area. The analysis showed that island habitats of modelled species were part of well connected sustainable network in the valley. Islands and patches of riparian forests on river banks facilitate dispersion and provide functional continuity of the Vistula corridor for mammals. The habitat management options analysis demonstrates potentially negative effects of river regulation on the spatial cohesion of habitats for mammals.