Water limitation prevails over energy in European diversity gradients of sheetweb spiders (Araneae: Linyphiidae)

Abstract

Across large spatial scales, species richness in many taxa is mainly determined by climatic variables. However, some of the mechanisms behind large-scale patterns of species richness and abundance are expected to act on the community level, and on a smaller scale than the resolution of the data commonly used for deriving these patterns. We studied the distribution of sheetweb spiders (Araneae: Linyphiidae) across Europe using both standardised samples from local habitats and large-scale inventories. In the first approach, we analysed species and individual numbers from standardised pitfall traps from 17 locations distributed from northern Sweden to Spain and Greece. We also calculated Simpson indices to correct for different activity densities. Additionally, we analysed whether diversity of sheetweb spiders is sensitive to habitat type. In the second approach, we investigated the known sheetweb spider species richness of European countries and large islands. In both datasets, species richness of sheetweb spiders reached a maximum at about 551N and declined towards the Mediterranean and the Arctic. In addition, species richness decreased from western (maritime) to eastern (continental) regions. Also Simpson diversity showed a hump-shaped relation to latitude, and was the only variable influenced by habitat type. In contrast to species richness and diversity, activity density increased monotonously with latitude. Towards the north, sheetweb spiders are likely limited by energy availability, towards the south, water limitation as well as bottom-up and top-down community interactions may reduce sheetweb spiders. Accordingly, their diversity does not follow the pattern of vertebrates, large insects and aquatic organisms, which depend more strongly on energy availability. Zusammenfassung

Small to large-scale patterns of ground-dwelling spider (Araneae) diversity across northern Canada

“…This result suggests that large-scale processes influence spider richness in northern Canada. However, unlike past work on spiders from Europe and Australia (Finch et al 2008;Kumschick et al 2009;Whitehouse et al 2009), we found that latitude was a poor predictor of diversity patterns in Canada. The longitudinal extent of this study and Canada's geography may partly explain this result.…”

Body size–climate relationships of European spiders

“…The second dataset was based on spiders captured with pitfall traps in the field‐site network of the EU‐project ALARM (Settele et al. , 2005; Kumschick et al. , in press).…”

A macro-scale perspective on within-farm management: how climate and topography alter the effect of farming practices

“…2003). For example, low precipitation is known to limit the distribution of spiders in southern Europe (Kumschick et al. 2009).…”

“…At a macro scale, precipitation generally plays a prominent role in diversity patterns of a wide range of taxonomic groups including invertebrate (Hawkins et al 2003). For example, low precipitation is known to limit the distribution of spiders in southern Europe (Kumschick et al 2009). Tetragnatha spiders particularly prefer wet environments as habitats (Yoshida 1981), which seems to be reflected in the strong effect of precipitation.…”