Pluralism in grassland management promotes butterfly diversity in a large Central European conservation area

Abstract

Extensively harvested grassland ecosystems contribute substantially to European biodiversity, but different kinds of grassland usage may selectively foster individual taxa. A combination of management options may offer a promising way to maximize biodiversity at the landscape scale. Here, we test this hypothesis based on 91 butterfly samples taken in the years 2013–2015 in differently managed areas within a large conservation area, the National Park Neusiedler See/Seewinkel in eastern-most Austria. Altogether, we recorded 4713 butterfly individuals of 35 species. Based on these records, we show that the parallelism of three management options, i.e. pasturing by mobile cattle herds, annual hay cut in early summer, and fallow land mulched in late summer, increase species diversity of butterflies and burnet moths in the regional meta-community. Even though spatial distances between our sample sites were small compared to the activity ranges of adult butterflies, we found that species composition of butterfly and burnet assemblages significantly differed between the three management options, indicating that assemblages were shaped by factors at the site level. Differences in species composition were stable across three consecutive years, even though there was annual variation in butterfly assemblages. Other tested co-variables (soil moisture, soil nitrogen, abundance of nectar flowers and local plant species richness) did not additionally contribute to explaining species composition of butterfly communities. We conclude that maintaining a combination of three complementary management options is indeed a relevant strategy for biodiversity preservation in this internationally renowned conservation area.