The role of hedgerows in shaping ant (Formicidae) communities in agricultural ecosystems: for a better understanding of agroecosystems functioning, including presumed ecosystem services and disservices

Abstract. Hedgerows are key components in the ecological functionality of mid-western European agricultural landscapes that have seen significant decline in the last 100 years due to intensive agriculture management. These infrastructures promote certain species in and around themselves that contribute to ecosystem services and disservices in farmland that have great socioeconomic fallouts. Few studies have explored how hedgerows shape biological communities and ecosystem (dis)services. Particularly, no study seems to have focused on ants (Formicidae). In the present research work, we explored the effects of both the distance from and management of hedgerows on ant communities. Ants were sampled in Allier, France, using 300 pitfall traps set at five different distances from 20 different hedgerows, categorized as either shrubby or arboreal. To perform taxonomic and functional analysis, we identified ants at the species level and built a functional traits database. We first observed that species richness was higher in arboreal hedgerows compared to shrubby ones. Factorial correspondence analysis (FCA) and redundancy analysis (RDA) also revealed a distance gradient, with greater compositional differences between communities near the hedgerows than those further away. Three functional indices, functional evenness (FEve), functional mean nearest neighbor distance (FNND) and functional dispersion (FDis), were correlated either with the distance gradient or the hedgerow type (arboreal or shrubby). We then identified several functional response traits that drive the functional diversity differences, such as behavioral dominance, worker polymorphism and colony foundation type. Four effect traits we presumed to be ecosystem (dis)services were studied and three of them – soil tilling, insect predation and aphid breeding/nectar thief – were affected in different ways by the distance from and management of hedgerows. This study offers valuable insights into how hedgerows shape agrobiodiversity, generally promoting outcomes beneficial to agriculture. While arboreal hedgerows may support greater ant diversity, shrubby hedgerows appear to provide (dis)services more closely aligned with agroecosystem needs. As a significantly more resilient alternative to intensive agricultural practices, which also threaten biodiversity, we argue that hedgerows will hold a strategic role in the necessary agroecological transition.