Long-term changes of steppe-associated wild bees differ between shell-nesting and ground-nesting species

Bees and wasps inhabiting steppe formations are, according to recent red lists, among the most endangered species, quickly disappearing from local faunas of central European countries. Several species, which are specialised nesters in empty gastropod shells, show the opposite pattern. Based on their distribution maps, we found that these species are recently more common and widespread than in the past. In contrast, the bee species nesting in the...