Abstract

Flood disturbances act as strong filters on arthropod communities by excluding species that are not adapted to the high water-tables. Sensitive species can survive in these areas by either migrating to more terrestrial habitats or by using dry refuges within the wetland created by topographical heterogeneity. In this study, we examined the role of such refugia and the scale at which these affect arthropod densities, mainly cursorial species, by using previous information on local dryness-wetness of wetlands, as expressed by inundation frequencies at a 2x2 m2 resolution. By focusing on spiders and beetles, these studies indicate that species within Linyphiidae, Staphylinidae and Chrysomelidae were more abundant in the presence of dry refuges at a scale of 10x10 m2, whereas Salticidae preferred wetter areas. Species within Carabidae, Lycosidae and a number of other taxon groups were indifferent to these structures. Moreover, the data seem to suggest that mainly habitat generalists benefit from the refuges. Accordingly, those groups that were impartial to the dry refuges included almost exclusively species that can be categorised as wetland specialists. More generally, the small-scale variability in wetland dryness-wetness creating small-scale refuges may be important to consider for guiding contemporary efforts to restore wetlands as a mean to promote biodiversity.