Butterfly fauna of different successional stages of extensively grazed calcareous grasslands in the Jura mountains

The butterfly faunas of 17 plots of different successional stages were investigated in the Jura mountains to study the consequences of succession on calcareous grasslands for butterflies. The four successional stages investigated were extensively grazed calcareous grassland, early fallow land (2-3 years without grazing), old fallow land (c. 10 years), and young forest (c. 20 years). A total of 8870 macrolepidoptera of 117 species and 3295 microlepidoptera of at least 43 species were recorded. The old fallow land hosted the most species and had the highest diversity. Its species composition was markedly different from the other stages. Methodology tests showed that for this kind of study, a plot size of 1000 m2 is adequate. For an ecological characterization and for comparisons between different sites species lists seem to be insufficient, the relative frequencies of the single species have to be taken into account as well.