A comparison of field margin establishment methods and impact on hymenopteran parasitoid communities

摘要

Field margins are an important refuge for biodiversity within intensively-managed ecosystems, and are targeted by many agri-environment schemes. This study investigated the effects of grassland field margin measures on hymenopteran parasitoid communities over 5 years. Fenced, rotavated and reseeded field margins had a significant impact on the abundance of parasitoids when compared with control and paddock plots. Overall parasitoid genera diversity did not differ significantly in relation to the three establishment methods. Established margins supported a different parasitoid community compared with control and paddock plots. Margin width and plant species richness had no significant impact on hymenopteran parasitoid communities. Grazing had a negative effect on the richness of parasitoids, suggesting that structural diversity of vegetation played an important role in community structure. In habitats where plant species richness is limited, simple biodiversity measures such as fencing of narrow field margins may be as effective at increasing parasitoid taxon richness and abundance as more expensive measures such as reseeding and wider margins.