Diversity of the Western Carpathian flysch grasslands: Do extremely species-rich plant communities coincide with a high diversity of snails?

Abstract

Upland fringes of the White Carpathians (Czech Republic) are known to support grasslands with the world’s highest local plant species richness. We investigated whether this unusually high plant richness has a parallel in snail communities, whether patterns of species composition of snail and plant communities in grasslands co-vary and how they are affected by local environment and landscape history. We compared plant and snail communities of dry to mesic grasslands in three neigh bouring regions: (1) hilly lowland of the Central Moravian Carpathians, (2) upland fringes and (3) upland of the White Carpathians. Both snail and plant communities exhibited a strong gradient in species composition associated with altitude, annual temperature and precipitation, soil calcium and pH. However, there was no correlation between local species richness of plants and snails in individual plots. The upland fringes of the White Carpathians were richest in snail species, probably due to intermediate environmental conditions, supporting the occurrence of species with contrasting environmental requirements. The highest local numbers of plant species were also recorded there, although differences among regions were not significant. The regional species richness of plants was also highest in the upland fringes, whereas that of snails was highest in the hilly lowland. Similarities in the diversity patterns of plants and snails among regions suggest the importance of regional factors for local richness, although local abiotic factors, which are partly correlated with the three regions, also influence local species composition and richness.