Grassland conservation headlands: their impact on invertebrate assemblages in intensively managed grassland

Published source details Cole L.J., McCracken D.I., Baker L. & Parish D. (2007) Grassland conservation headlands: their impact on invertebrate assemblages in intensively managed grassland. Agriculture, Ecosystems & Environment, 122, 252-258.
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This study is summarised as evidence for the following.

	Action	Category
	Reduce grazing intensity on grassland (including seasonal removal of livestock) Action Link
	Leave headlands in fields unsprayed (conservation headlands) Action Link

Reduce grazing intensity on grassland (including seasonal removal of livestock)

A replicated, controlled study of five grassland headlands on four intensively managed pastoral farms across Scotland (Cole et al. 2007) investigated the effect of conservation headlands, with no grazing from April-August and no fertilizer or pesticide applications on the abundance of ground active invertebrates and found that aphids/leafhoppers/planthoppers (Homoptera) and true bugs (Heteroptera) were more abundant in conservation headlands (no fertilizers, pesticides or grazing April-August) than conventional headlands and open fields. Aphids/leafhoppers/planthoppers had higher activity densities in conservation headlands (2.1) and field edges (conventional: 2.0, conservation: 1.9) than in conventional headlands (0.8) and open fields (0.6). Roundback slugs (Arionidae) showed the same pattern (2.3 conservation headlands, 2.1 conventional field edges, 2.4 conservation field edges, 0.7 conventional headlands, 0.3 open fields). True bugs were more abundant in conservation headlands (0.7) and field edges (1.1-1.2) than in open fields (0.2). Keelback slug (Limacidae) activity density was greater in both headlands (conventional: 1.9, conservation: 2.8) and field edges (2.3-2.7) than in open fields (1.1). Butterfly/moth (Lepidoptera) and sawfly (Symphyta) larvae showed a similar trend, whereas ground beetle (Carabidae) abundance did not differ with treatment (3.5-3.6). Ground beetle activity density was highest in open fields (4.0). One headland in each field was divided into two areas of 6 x 100 m, a conventional and conservation headland. In each field, invertebrates were sampled with five pitfall transects of nine traps in: the conservation headland, conservation field edge, conventional headland, conventional field edge and open field. Traps were set for 3–4 weeks in May-June and July-August 2000-2003.
Leave headlands in fields unsprayed (conservation headlands)

A replicated, controlled study in 2000-2003 of five grassland headlands on four intensively managed pastoral farms across Scotland (Cole et al. 2007) found that aphids/leafhoppers/planthoppers (Homoptera) and true bugs (Heteroptera) were more abundant in conservation headlands (no fertilizers, pesticides or grazing April-August) than conventional headlands and open fields. Homoptera had higher activity densities in conservation headlands (2.1) and field edges (conventional: 2.0, conservation: 1.9) than in conventional headlands (0.8) and open fields (0.6). Roundback slugs (Arionidae) showed the same pattern (2.3 conservation headlands, 2.1 conventional field edges, 2.4 conservation field edges, 0.7 conventional headlands, 0.3 open fields). True bugs were more abundant in conservation headlands (0.7) and field edges (1.1-1.2) than in open fields (0.2). Keelback slug (Limacidae) activity density was greater in both headlands (conventional: 1.9, conservation: 2.8) and field edges (2.3-2.7) than in open fields (1.1). Butterfly/moth (Lepidoptera) and sawfly (Symphyta) larvae showed a similar trend, whereas ground beetle (Carabidae) abundance did not differ with treatment (3.5-3.6). Ground beetle activity density was highest in open fields (4.0). One headland in each field was divided into two areas of 6 x 100 m, a conventional and conservation headland. In each field, invertebrates were sampled with five pitfall transects of nine traps in the conservation headland, conservation field edge, conventional headland, conventional field edge and open field. Traps were set for 3–4 weeks in May-June and July-August 2000-2003.