Effect of adjacent steppe-like habitats on spider diversity in vine plants

Spiders are important natural enemies of pests in many agroecosystems. Spiders’ diversity and abundance—and therefore their biological control potential—often increases with the presence of non-crop habitats adjacent to the agroecosystem and/or the abundance of such habitats in the landscape. This research aims to determine whether spider communities dwelling on vine plant trunks are richer and more abundant in terraced vineyards than in plain vineyards. We found that spiders’ abundance and species richness were significantly greater during part of the season in the plain than the terraced types of vineyards. The abundance of spiders on the vine plants in the terraced vineyards decreased gradually from the field margins to the centre while no such pattern was observed in the plain vineyards. Subsequent experiments will be needed in order to elucidate the role of the individual mechanisms and parameters that underpin our findings. For example, the air flow (direction and intensity), the presence of the predators, heterogeneity and the presence of shrubs on the slopes of terraces should be studied further. Particularly, because our findings contradict the general assumption that terraced vineyards should host richer spider communities.