Effect of sward type and management on butterfly numbers in the uplands

摘要

A four-year systems experiment is quantifying the economic and environmental impacts of a) mixed grazing of sheep with cattle, and b) the removal of cattle from mixed systems on improved permanent pasture to graze Molinia-dominant semi-natural rough grazing (SNRG) during the summer months. As part of this study regular butterfly surveys are being carried out throughout the summer on a total of 26 experimental plots. The plots surveyed contain swards managed in three different ways: 1) ryegrass/ whiteclover-dominant improved permanent pasture grazed by livestock throughout the growing season (n=10); 2) improved permanent pasture grazed in spring, then closed-up in May for one cut of silage, followed by aftermath grazing (n=10); 3) Molinia caerulea-dominant semi-natural rough grazing (SNRG) grazed by cattle from June to September (n=6). Sward type was found to have a significant effect on the number of butterflies recorded (P < 0.001), with substantially higher numbers observed on the SNRG.