Work

Pesticide-free fields under minimum tillage and flower strips enhance carabid beetles and spiders through increased overwintering and spill over processes

Year: 2026

Type: article

Abstract: Enhancing generalist arthropod predators in arable farming can contribute to pest control and pesticide use reduction, and be achieved through a diversity of management options at field and farm scales. Most studies however link management options to densities of circulating adults, which gives little insight into potential source-sinks dynamics and the occurrence of ‘source’ habitats enabling overwintering. In this study, we assessed the assemblages of emerging and circulating ground-dwelling carabids and spiders during four months in a continuous mosaic of pesticide-free winter-sown crops under contrasted tillage regimes (minimum vs. conventional tillage) and sown flower strips bordering fields. We detected clear patterns, with high in-field carabid and spider overwintering densities than in adjacent flower strips, which were rarely a preferred overwintering habitat. Our results nevertheless indicate that within both taxa, different species exhibit different responses and source-sink dynamics. Our results also demonstrate the key role of pesticide-free fields under minimum tillage, acting both as a high-quality overwintering site for some dominant carabid species and as a source habitat, as several predator species activity-density responded positively to the increased area of minimum tillage fields in the surroundings. We detected a comparable positive effect of the area of flower strips in the surrounding for some species, suggesting that these linear features could also act as a temporary refuge and source. These findings highlight that sustaining diverse communities of carabid beetles and spiders probably requires adopting several and complementary management options and that in-field farming practice represent a powerful lever to foster natural enemies populations. • High carabid and spider overwintering densities were found in pesticide-free fields. • Carabid beetles benefitted more from minimum-tillage fields than flower strips. • Flower strips sheltered numerous agrobiont and rare overwintering spider species. • Spillover towards fields occurred both from minimum-tilled fields and flower strips.

Source: Agriculture Ecosystems & Environment

DOI: 10.1016/j.agee.2026.110250

Authors: Paul Bannwart, Antoine Gardarin, Violaine Deytieux, Stéphane Cordeau, Sandrine Petit