Effects of wild boar (Sus scrofa) rooting on abandoned calcareous grassland in Hainich National Park, Germany

Calcareous grasslands are semi-natural biodiverse ecosystems that hold high conservation value, but are threatened throughout Europe. Abandoned calcareous grasslands become afforested unless succession is reset. We tested the idea that wild boar (Sus scrofa) rooting activity could serve as a means to reset succession and thereby maintain characteristic herbaceous plant diversity in calcareous grasslands. We compared vascular plant abundance and environmental parameters between plots rooted by wild boar and undisturbed plots in unmanaged calcareous grasslands in Hainich National Park, Germany. We found that rooted plots had lower grass cover and higher herb cover, and a significantly higher species richness, Shannon diversity index and evenness. Indicator species analysis differentiated 23 species for rooted plots, and 8 for undisturbed plots. Of 17 characteristic species for calcareous grasslands, two were significant indicators in rooted plots, and one in undisturbed plots, while 14 did not differentiate between the treatments. Our findings suggest that wild boar rooting activity in Hainich National Park may maintain characteristic calcareous grassland vegetation, by resetting early grassland succession and enhancing heterogeneity, which in turn helps sustaining biodiversity.