Restoring a butterfly hot spot by large ungulates refaunation: The case of the Milovice military training range, Czech Republic

Abstract

Background: Refaunation/rewilding by large ungulates represents a cost-efficient approach to managing natural biotopes and may be particularly useful for areas, whose biodiversity depends on disturbance dynamics and is imperilled by successional changes. To study impacts of refaunation on invertebrates, we focused on butterflies inhabiting the former military training range Milovice, Czech Republic, refaunated since 2015 by a combination of Exmoor pony (“wild” horse), Tauros cattle (“aurochs”) and European wisent.Methods: We compared butterfly presence-absence patterns immediately after the military use termination (early 1990s), prior to the refaunation (2009) and after it (2016–19); and quantitative data gained by monitoring butterflies at refaunated and neglected plots. We used the correspondence analysis for the presence-absence comparison and the canonical correspondence analysis for the quantitative data, and related results of both ordination methods to the life history, climatic and conservation-related traits of recorded butterflies. Results: Following the termination of military use, several poorly mobile species inclining towards oceanic climates were lost. Newly gained species are more mobile and prefer warmer continental conditions. The numbers of butterfly species did not differ between refaunated and neglected plots, but the former hosted higher abundances. Butterflies developing on coarse grasses and shrubs inclined towards neglected plots, whereas refaunated plots supported species developing on small forbs. Conclusion: The changes in species composition following the cessation of military use were attributable to successional change, coupled with climate-driven changes in species pool. By blocking succession, large ungulates support butterflies depending on competitively poor plants. Restoring large ungulates populations represents a great hope for conserving specialised insects, provided that settings of the projects, and locally adapted ungulate densities, do not deplete resources for species with often contrasting requirements.