The effect of restoration techniques on flora and microfauna of hawthorn-dominated hedges.

Manage hedgerows to benefit wildlife (includes no spray, gap-filling and laying)

A replicated, controlled, randomized study of 14 hedges at ten sites throughout Northern Ireland in 1991 (McAdam, Bell & Henry 1994) found that hard coppicing increased numbers of plant species and laying increased numbers of invertebrate species. Treatments had higher numbers of plant species/plot compared to the control (26), but this was only significant for coppicing (with planting in gaps; 31-34), not pollarding (28) or laying (27). There were significantly more invertebrate orders in laid hedges (4.1) than the control (2.6). Numbers in coppiced (3.6-3.8) and pollarded (3.2) hedges did not differ significantly from the control. There were similar numbers of plant species and invertebrate orders in Environmentally Sensitive Area and non-Environmentally Sensitive Area hedges.  The 14 hedges were dominated by hawthorn Crataegus monogyna, had 150 m of uniform height and density of trees, had permanent pasture on both sides and were largely overgrown and unmanaged. The five treatments were applied to 25 m lengths of each hedge. Hedges were fenced to exclude grazing and were cut to 1.5 m each third year where appropriate. Plants were listed within each plot during the summer. Invertebrates were sampled using shelter traps (20 x 5 cm) in the hedgerow canopy during May. Additional plant data are available for 1992 and 1994 (McAdam et al. 1996).