Recent artificial vineyard terraces as a refuge for rare and endangered spiders in a modern agricultural landscape

Many xerothermophilic invertebrate species have become rare and endangered due to intensified agriculture and forestation during the last decades. An important question is whether human-made habitats may serve as refuges for rare xerophilous species inhabiting disappearing seminatural and natural locations. We studied spider assemblages of several vineyard terraces in the traditional wine region of the Czech Republic and investigated factors from microhabitat to landscape scale that could influence conservation usefulness of terraces. Species density, abundance, conservation value and degree of rareness were analyzed for conservation-important spider species on terraces with two succession-stage habitat types (sparse versus dense grass) in landscapes with varying proportions of surrounding potential source areas and different surrounding habitats. A total 171 species of spiders were recorded, with high proportions of rare xeric specialist (40%) and red-listed threatened species (15%) that supports the conservation potential of vineyard terraces. The conservation significance of terraces is affected by factors operating at (micro) habitat and landscape scales. Overall species density and spider abundance did not differ significantly between terraces with sparse versus dense vegetation cover. Rare and endangered epigeic species were associated with terraces having sparse vegetation while rare epiphytic species were associated with terraces having dense vegetation. Species density, conservation value, degree of rareness and abundances of red list and rare species increased with presence of adjacent steppe grasslands. Our results indicate such artificial habitats can be important refuges for a wide spectrum of xerothermophilic spiders. To prevent losses of rare and endangered xeric species, we suggest agricultural interventions and management methods that retain important diversification of microhabitats.