Moth communities and agri-environment schemes : examining the effects of hedgerow cutting regime on diversity, abundance, and parasitism

1. Hedgerows provide an important habitat for wildlife including invertebrates, representing a large proportion of semi-natural habitat patches in the modern agricultural landscapes of the UK and Europe. Around 40% of hedgerow length in England is managed under agri-environment scheme (AES) options, which specify less frequent cutting and advise cutting in winter. 2. Hedgerow management can alter habitat structure and quality, potentially influencing invertebrate community structure. We assessed the impacts of management treatments on moth communities and their parasitoids. Two treatments ('cutting frequency': once every 1, 2, or 3 years, and 'cutting time': autumn vs. winter) were applied to a long-running hedgerow experiment, mimicking AES prescriptions. Moth larvae were collected from the hedgerows, identified and reared to determine parasitism. Hedgerow structure and foliar quality were quantified and related to changes in moth abundance, diversity, species richness, and parasitism. 3. Hedgerow management did not significantly affect overall abundance of moth larvae, but did affect the abundance of certain feeding guilds and trophic interactions with parasitoids. Concealed moth larvae (mining, tentiform, and case bearing) were more abundant on hedgerows cut infrequently (every 2 or 3 years vs. annually). Parasitism rates were higher on hedgerows cut less often, when these were cut in autumn. There was a strong trend towards greater moth species richness and diversity on winter cut hedgerows. 4. Agri-environment scheme management can thus have complex effects on invertebrate communities. The abundance of some moths may be positively affected by AES hedgerow management and this can have knock-on effects on parasitoid abundance.