Diurnal Lepidoptera: Sensitive Indicators of Cultivated and Abandoned Grassland

(1) In the subalpine region of Central Switzerland (Tavetsch Valley) studies were made of the day-active Lepidoptera faunas in different types of cultivated grassland, in various stages in the development of abandoned grassland and in woodlands (climax vegetation). (2) The results show a close correlation between bufferfly fauna and vegetation type concerning species composition and species richness of Lepidoptera. (3) Species richness of butterflies is highest in early abandoned stages and falls rapidly with the arrival of shrubs and trees. It is also high in traditionally lightly cultivated grassland (unfertilized mown and lightly grazed meadows), but it declines drastically with increasing intensity of cultivation. (4) In general, species richness of butterflies is closely correlated with species richness of vascular plants, but cultivation methods and the short time since abandonment (<5 years) of lightly cultivated grassland have strongly different influences on species richness of Lepidoptera and vascular plants. (5) The results are in contrast to former studies in Central Europe and parallel studies in England. (6) The natural primary habitats of butterflies living in the anthropogenetic types of vegetation investigated and the consequences for nature conservation are discussed.