Contrasting needs of grassland dwellers: habitat preferences of endangered steppe beetles (Coleoptera)

Temperate grasslands are local biodiversity hotspots. In Europe, their extent was mostly reduced to isolated habitat patches, whose biota is subject to extinction debt. Knowledge on requirements of dry-grassland inhabitants is thus vital to slow down decline of grassland biodiversity. We studied habitat requirements of eight flightless steppe beetles, including some of the most endangered dry-grassland specialists of the continent. The beetles were sampled using 167 pitfall traps at a pannonian dry-grassland fragment, the Pouzdrany steppe, SE Czech Republic, from March to November 2006. The number of each species captures in each trap was related to vegetation and abiotic habitat characteristics; captures of all beetles were related to each other. Two of the studied species required relatively humid microhabitats, including tall-grass steppe with litter (Carabus hungaricus, Carabidae) and grassland of high herb cover (Meloe proscarabaeus, Meloidae). Others were associated with xeric habitats (e.g. Meloe scabriusculus) and their early-successional stages, including short-turf vegetation (Dorcadion fulvum, D. pedestre, Cerambycidae) and/or bare-ground patches (Blaps lethifera, Tenebrionidae; Meloe decorus, M. uralensis). Our findings point to key importance of early-successional vegetation for grassland biodiversity, and to the fact that locally co-occurring and closely related grassland specialists may exhibit contrasting habitat needs. Spatially and temporarily highly diversified patch management creating a fine scale mosaic of various seral stages from bare soil to tall-grass steppe is therefore the most appropriate approach for managing isolated grasslands. Prescribed burning and support of burrowing herbivores are recommended and discussed together with other measures for restoration of habitat diversity in dry-grassland fragments.