Butterflies in corridors: quality matters for specialists

Agricultural intensification and subsequent landscape homogenisation have caused severe losses of insects across major parts of Europe. In consequence, most animal and plant populations today exist in small and isolated habitat patches. Thus, there is an urgent need to increase landscape permeability to foster the exchange of individuals and thereby to promote the long-term persistence of populations and species. Corridors can help to connect local habitats and populations. Nonetheless, whether species use a corridor and how species behave in a corridor strongly depend on species' ecology and the quality of the corridor. In this study, we analysed the behaviour of 753 individuals of five butterfly species of the subfamily Satyrinae (Coenonympha pamphilus, C. arcania, Maniola jurtina, Melanargia galathea, and Erebia medusa) in a high-quality habitat, in two corridors with different habitat qualities, and in arable fields. Butterflies undertake more frequent and much longer flights in arable fields, and a more range-restricted behaviour with perching and visiting of flowers in corridors and inside the original high-quality habitat. Specialist butterflies only rarely leave the corridor and fly into the matrix if compared with generalist butterfly species. Furthermore, the relative difference in the probability of leaving a corridor was much more pronounced between the two corridor qualities for specialists than for generalists. In conclusion, corridors with high habitat quality, such as many flowering plants, support species and population persistence. Specialist species especially respond to corridor quality, such as the availability of flowers or a calcareous grassland-like species composition.