Effect of woodland vegetation on arthropod abundance, species composition and predation in adjacent vineyards

Natural habitats in agricultural landscapes increase heterogeneity and support diverse arthropod communities with multiple ecosystem functions. However, the vegetation characteristics that most influence these communities remain unclear. Our study analysed how forest vegetation affects arthropod abundance, family composition and predation in forests and adjacent vineyards. All plant species were identified in forest plots close to each of 13 vineyards in southeastern France. Additionally, the cover of flowers, trees, shrubs and herbaceous vegetation was estimated. Arthropods were sampled using sticky traps placed in forests, vineyard borders, and inner vineyard rows. Captured arthropods were identified and assigned to functional groups. Predation rates were measured using sentinel cards with Lucilia larvae. Arthropod community composition differed between forests and vineyards, with woodland samples being more associated with parasitoids and predator groups, whereas vineyard samples were more associated with phytophagous taxa. Arthropod abundance in forest fragments was not significantly related to abundance in adjacent vineyard borders or inner rows. However, abundance was higher on the forest-facing side of sticky traps in vineyard borders than on the vineyard-facing side, suggesting directional movement from forests into vineyards. At vineyard borders, trap orientation also influenced arthropod community composition. Vegetation effects were strongest at the vineyard border, particularly flower cover, that positively influenced nearly all arthropod groups. Vineyard predation was positively related to predation in adjacent forests. Total vegetation and shrub cover of forests affected predation in vineyards, confirming that woodland vegetation structure can influence biocontrol service. Although many effects were concentrated at the vineyard border, our findings highlight the key role of forest fragments in maintaining arthropod diversity and promoting ecosystem services in agroecosystems, particularly through floral resources.