Limestone quarries as refuges for European xerophilous butterflies

The large-scale decline of traditionally managed early-successional habitats caused by the joint effects of agricultural intensification and abandonment of marginal lands has resulted in a continent-wide decline of xerophilous butterflies throughout Europe. The question is whether newly generated early-successional sites of industrial origin may partially compensate for this habitat loss. We studied the butterfly assemblages of 21 limestone quarries in the region of Moravia, Czech Republic, within an important corridor of latitudinal faunal migrations, the Moravian Gate. Comparison of species abundances in the quarries with their regional distribution allowed us to delimit a group of species, predominately xerophilous and sedentary, for which the quarries serve as refuges. Total species richness, number of species in the group, and numbers of xerophilous and sedentary species increased toward the south and were high in young and actively operating quarries and in quarries that adjoined warm "steppe" grasslands. Canonical correspondence analyses suggested that habitats within the quarries and adjoining habitats explained much higher proportions of variance than either latitude or the variables related to quarrying. However, the positive effects of southern position and active quarrying were highly significant. Both xerophilous species of the earliest-succession barrens and of later-succession scrub inhabited the quarries, owing to the inherent heterogeneity of such sites. It follows that quarrying does not harm the priority butterflies and may be regarded as a method of habitat creation, provided that (1) the operators support habitat heterogeneity within the quarries, (2) xerophilous sites in the vicinity are preserved and adequately managed, and (3) other phenomena of conservation importance are not adversely affected.