Orthoptera in the early stages of post-arable rewilding in Suffolk

Dr Tim Gardiner

Presentation

Reversion of arable farmland to grassland and scrub habitats on Black Bourn Valley nature reserve in Suffolk through non-intervention allowed succession to occur largely unmanaged. Fields in the early stages of rewilding (4–14 years) are found at Black Bourn Valley, while pond creation has been extensive since 2010, creating water edge habitat and heterogeneity to the re-establishing grassland. Monitoring of Orthoptera (good indicators of habitat heterogeneity and important in food chain) with Dorothy Casey revealed that species diversity/richness and several grasshopper/groundhopper species were in higher abundance in fields ≥8 years since arable cropping ceased compared to those 4 years post reversion. Fields ≥8 years old were probably favourable due to the presence of microhabitats for basking and egg- laying orthopterans that included ant hills, sparsely vegetated pond edge and open swards with an abundance of fine-leaved grasses (bents and fescues) and a low abundance of leaf litter. Lagomorph grazing by brown hare and rabbit was critical in maintaining exposed soil for Orthoptera in the older fields, while deer paths appeared to create microhabitats that may be utilised by Orthoptera.