Little and late: How reduced hedgerow cutting can benefit Lepidoptera

• Hedgerows provide breeding habitat, shelter and nectar for Lepidoptera.
• Three management treatments were tested using a large-scale field experiment.
• Management effects over three years varied with Lepidoptera life history traits.
• Cutting hedges less often, less intensively and in winter benefits most Lepidoptera.
• Hedgerow agri-environment schemes benefit Lepidoptera but could be improved further.

Hedgerows are a key semi-natural habitat for biodiversity in intensive agricultural landscapes across northern Europe and support a large invertebrate fauna. Management can have large effects on the value of hedgerows as a wildlife habitat, thus sensitive management is incentivised through agri-environment schemes (AES). We tested how current and potential future AES hedge management regimes affected the diversity and abundance of Lepidoptera species that utilise the hedge as a breeding resource, using a long term, multi-site, manipulative field experiment. Hedgerow management in some current AES options (reduced trimming frequency and cutting in winter) increased Lepidoptera abundance and the diversity of components of the Lepidoptera community linked with specific lifecycle traits. However, the most frequently applied hedgerow AES option currently applied in the UK (cutting once every 2 years in autumn) did not benefit Lepidoptera compared to standard hedgerow management outside AES (annual trimming in autumn). Decreasing the intensity of hedgerow trimming improves the diversity of the whole Lepidoptera assemblage, and should be considered as part of biodiversity conservation in farmed landscapes.