Roe deer diet was studied in the floodplain forest of South Moravia, Czech Republic, by analysis of faecal samples collected in six different parts of the study area. Woody plants were the main component of roe deer diet, and they were supplemented with bramble, forbs and grasses through the year. The composition of roe deer diet agreed with its foraging strategy and consisted mainly of browse. Floodplain forest is optimal for roe deer and offers sufficient food sources. Food sources from nearby fields have no influence on the diet of roe deer. The great potential of roe deer to influence the shrub layer is evident. The intensity of impact of roe deer was not affected by availability of other food sources in the floodplain forest. The impact of roe deer on woody plants in this habitat depended mainly on its population density. Therefore, protection and management of floodplain forest is related to the regulation of densities of ungulate species, and not on additional feeding.
Species diversity and potential impact of cocoon parasitoids on the abundance of the common pine sawfly, Diprion pini L. (Hymenoptera: Diprionidae), were explored in different forest habitats, with endemic sawfly populations, by the regular exposure of laboratory reared sawfly cocoons. Different cocoon spinning sites of the sawfly were simulated by exposing cocoons at several strata (soil, litter, trunk and stem of pine trees) in a forest. In more fertile, mixed spruce/pine-forests, parasitism on exposed cocoons was lower than in typical outbreak stands with a lower vegetational diversity. The parasitoid communities comprised of up to nine parasitoid species, which showed temporal and spatial niche separation. The ichneumonid Pleolophus basizonus Grav. (Hymenoptera: Phygadeuontinae) occured throughout the season at all strata as well as in all forest types. The ichneumonid Gelis cursitans F. (Hymenoptera: Phygadeuontinae) was only found in pine forests with sparsely developed ground vegetation, parasitizing exposed cocoons in the upper story in spring. The torymids Monodontomerus dentipes Dalm. (Hymenoptera: Torymidae) and M. minor Ratz. (Hymenoptera: Torymidae) were present in all forest types, but parasitized commonly only cocoons in the upper story in summer. Apparently, these generalists can quickly respond to increased densities of upper story exposed "summer" cocoons and thus limit the population growth of the pine sawfly due to the development of a second generation.