Riparian buffer zones in intensive grassland agri-systems are not necessarily a refuge for high conservation value species

Abstract

The appropriate management of natural riparian zones can provide numerous ecosystem services within an agricultural landscape, including the enhancement of regional biodiversity. Management of riparian zones has featured in Irish agri-environment schemes. We investigated the biodiversity of riparian field margins which had been fenced to provide water quality and biodiversity benefits. Surveys of plants, carabid beetles and spiders were conducted in typical habitat types that occur in riparian zones (grassland, scrub and woodland) on intensively-managed grassland systems in the south-east of Ireland. Distinct assemblages of plants and spiders were identified in each habitat type, but this was not the case for carabids. There were higher abundances of carabids and spiders in grass dominated riparian margins, while scrub dominated margins provided the highest regional carabid species richness. Riparian zones in intensively farmed areas in this study had a low incidence of specialised fauna. Proportional abundances or frequencies of riparian or wetland species for the surveyed flora and fauna were low when compared to the national flora and fauna and other similar studies. Management prescriptions in addition to those currently employed, such as limited grazing of fenced watercourse zones, may increase the abundance and/or species richness of some taxonomic groups. These results highlight the need for more appropriate management prescriptions and targeting of management actions if agri-environment measures aim to conserve farmland biodiversity in riparian zones.