Spiders in vineyards show varying effects of inter-row management and the surrounding landscape

Abstract

In vineyards, management and the surrounding landscape can have different effects on spiders. In temperate regions management (organic vs. conventional) may have less strong effects than for other crops. Nevertheless, spiders can benefit from a more natural landscape surrounding the vineyards. To investigate effects on spiders in vineyards beyond the general management regime, we conducted a study in 32 organically managed vineyards with different landscape configuration (vineyards adjacent to hedgerows vs. surrounded by other vineyards). Additionally, in one half of all vineyards the inter-rows were sown with a species-rich cover crop mixture and in the other half were left to spontaneous vegetation. The spider community was assessed by sampling canopy-dwelling spiders with beat-sheets and ground-dwelling spiders with pitfall traps.

Spider communities, analysed at the family level, showed significant differences between the canopy and ground stratum. The overall abundance of spiders in both strata was neither effected by the inter-row vegetation nor by the surrounding landscape. The diversity of spider families in the canopy was positively influenced by adjacent hedgerows. However, spider families responded differently to hedgerows; for example, we found more Araneidae in vineyards without adjacent hedgerows.

The ground-dwelling community was dominated by a single species (Pardosa agrestis) and no effects on the species diversity were found. Still, species also showed different reactions, for example Zodarion italicum benefitted from spontaneous vegetation. These results show that the impact of inter-row vegetation management and hedgerows on spiders in vineyards is variable and sometimes unexpected.