The response of sward-dwelling arthropod communities to reduced grassland management intensity in pastures

We compared arthropod taxon richness, diversity and community structure of two replicated grassland husbandry experiments to investigate effects of reduced management intensity, as measured by nutrient input levels (390, 224 and 0 kg nitrogen ha-1 yr-1 in one experiment, and 225 and 88 kg nitrogen ha-1 yr-1 in another). Suction sampling was used to collect Araneae, Coleoptera, Hemiptera and Hymenoptera, with Araneae and Coleoptera also sampled with pitfall trapping. Univariate analyses found no significant differences in abundance and species density between treatments. However, with multivariate analysis there were significant differences in arthropod community structure between treatments in both experiments. Reducing nitrogen input and associated stocking rates, as targeted by agri-environment schemes, can significantly alter arthropod communities, but without increasing the number of species present. Other approaches that may be necessary to achieve substantial enhancement of sward arthropod biodiversity are suggested.