Abstract. 1. Arthropods, a major component of functional biodiversity within agro-ecosystems, contribute to sustainability through processes including nutrient cycling and pest control. Extensively managed field margins can help protect this functional biodiversity by providing habitat for beneficial species.
2. This 2 year study investigated the relative benefits of grassland field margin treatments (Fenced only, Rotavated, and Reseeded (with a grass and wildflower mixture)) on the abundance and taxon richness of five arthropod trophic groups (detritivores, herbivores, predators, parasitoids and hyperparasitoids) from the orders Coleoptera, Hemiptera, Hymenoptera, Diptera and Araneae.
3. The taxon richness and abundance of all trophic groups (with the exception of herbivore abundance) was greater in fenced field margin treatments than in the adjacent grazed field, particularly by the final sampling occasion. However, there were seasonal differences, with abundance and taxon richness generally greater in August than in June. Only detritivores and herbivores responded to the individual fenced field margin treatments. The botanically more species rich, rotavated and reseeded treatments, had greater detritivore and herbivore richness and abundance than the fenced only treatments.
4. Community structure analysis indicated that the grazed (within) field and fenced field margins had two distinct communities for all trophic groups, demonstrating the conservation value of the margins within intensively managed agricultural grasslands.
5. The current Irish agri-environment scheme requires fencing of field margins. Our results highlight how this relatively simple measure can benefit arthropod conservation and functional biodiversity. This may in turn benefit farm productivity through potentially improved nutrient cycling and natural pest control.