Habitat niches suggest that non-crop habitat types differ in quality as source habitats for Central European agrobiont spiders

Abstract

Non-crop habitats in agricultural landscapes may differ in their potential to serve as source habitats for natural enemies. To determine this potential for different habitat types, it is crucial to understand habitat preferences and the habitat niche width of natural enemies. In addition, populations of natural enemies are affected by management practices depending on their preferences for habitat strata. Here we analysed agrobiont spider preferences (very common species in arable fields) for different microhabitats (ground, herbaceous, and shrub strata) and non-crop habitats (agroecosystems, forests, scrub, meadows, steppe, and wetlands). We compared guild-specific preferences of cursorial and web-building spiders that inhabit pome fruit orchards and cereal fields using two databases on Central European spider preferences. The majority of agrobiont spiders showed a moderate niche width. Agrobiont spiders from orchards preferred the shrub stratum while spiders from cereal fields preferred the ground and herbaceous strata across habitats. Agrobiont spiders primarily utilized non-crop habitats that were structurally similar to a particular agroecosystem: spiders from orchards utilized mostly woody vegetation while spiders from cereal fields utilized mostly meadows. Moreover, cursorial and web-building spider species from cereal fields differed in their preferences for different non-crop habitats. The results highlight that non-crop habitats have different potential as sources of agrobiont spiders. The composition of non-crop habitats in agricultural landscapes may affect the functional composition and pest control potential of spider communities. Further studies focusing on the effects that landscapes have on natural enemies in local agroecosystem need to account for the identity of non-crop habitats.