Recent changes in agriculture (intensification or abandonment) have resulted in a critical reduction of steppe-like grasslands in Eastern Europe. These grasslands harbor an extraordinarily high diversity of plants and invertebrates, including endemics, and are considered refugia for numerous threatened open-land species. We examined species richness, and abundance, proportion of open-land, endemic and threatened vascular plants, gastropods, and diurnal and nocturnal Lepidoptera in six different vegetation types all originating from steppe-like grasslands in Transylvania, Romania. Vegetation types included extensively grazed pastures (initial stage), three seral stages of succession (early stage of abandoned grassland, abandoned grassland with shrubs, and mature forest), and two human-made grassland alterations, namely abandoned vineyards and Pinus plantations. A total of 852 species (291 vascular plants, 24 gastropods, 129 diurnal and 408 nocturnal Lepidoptera) were found in the 22 study sites. The four taxonomic groups differed in their response to the abandonment of steppe-like grassland, except that species richness of plants and diurnal Lepidoptera were positively correlated. The complementarity of species composition increased with successional age in all taxonomic groups examined. The number of characteristic open-land species decreased with successional age in plants and gastropods. All investigated vegetation types harbored threatened (red-listed) species. Endemic species were found in all vegetation types except mature forests and Pinus plantations. All Transylvanian endemics and the majority of threatened species found were open-land species. Extensively cultivated vineyards, which have been abandoned for two to three decades, also maintained high plant and invertebrate diversities, comparable to those of the corresponding stages of grassland succession. In contrast, Pinus plantations (a recent grassland alteration) have changed habitat quality and will have a devastating effect on the unique, indigenous diversity of these steppe-like grasslands as soon as the canopy closes. To prevent losses of characteristic species, we suggest a rotational grassland management program that maintains different seral stages. Succession to mature forest and additional Pinus plantations should be prevented. Resumen: Cambios recientes en la agricultura (intensificación o abandono) han resultado en la reducción crítica de pastizales similares a estepas en Europa Oriental. Estos pastizales albergan una diversidad extraordinariamente alta de plantas y animales, incluyendo endémicos, y son considerados refugios para numerosas Cremene et al. Biodiversity in Eastern European Grasslands 1607 especies amenazadas. Examinamos la riqueza y abundancia de especies, la proporción de plantas vasculares, gasterópodos y Lepidoptera diurnos y nocturnos amenazados y endémicos en seis tipos de vegetación diferentes pero originados a partir de pastizales similares a estepas en Transilvania, Rumania. Los tipos de vegetación incluyeron pastizal...

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The effect of road width on dispersal in the land snail Arianta arbustorum was examined by recording displacements of marked individuals during one activity season (3 months) in central Sweden. For two sites, a paved road (8 m wide, low traffic density) and an unpaved track (3 m wide), the snails' movements were largely confined to roadside verges. The snails followed the vegetation belts; the average displacements ranged from 1.5 to 4.9 m at different sites. Several snails covered large distances, the maximum recorded being 14 m. Despite these long-distance dispersers, only one of the recaptured snails crossed the paved road and two crossed the track, indicating that the road and, to a minor extent, the track acted as dispersal barriers. By contrast, an overgrown path (0.3 m wide) did not influence the snails' movement. Our results suggest that snail populations separated by paved roads with high traffic densities may be isolated from each other.

A laboratory experiment was conducted to determine the damage caused by snail grazing to 35 calcicolous lichen species and cyanobacteria from the Baltic island of Oland, Sweden. Individuals of four species of land snails (Balea perversa, Chondrina cliema, Clausilia bidentata and Helicigona lapicida) were allowed to graze on identified lichen species growing on pieces of limestone. Snail grazing on thalli and ascocarps was classified into four categories ranging from no damage to completely eaten. In general, some lichen species were heavily grazed, whereas others were only slightly damaged or not injured. Aspiciha calcarea, Tephromela atra and Verrucaria nigrescens were preferred by all snail species except Chondrina cliema. In general, lichen thalli that were not immersed in the calcareous rock and cyanobacteria were preferred, whereas ascocarps were avoided by one of the snail species (C. clienta). Immersed perithecia with a carbonized outer layer were avoided by all snail species except C. bidentata. Possibilities of chemical and mechanical defence properties in calcicolous lichens are discussed.

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