Orthoptera in the early stages of post-arable rewilding in south-east England

Abstract

The ideal aim of rewilding is to restore natural processes to create ‘self-willed’ ecosystems involving the creation of large areas of habitat subject to stochastic disturbance, connected by favorable corridors for species to disperse along. Reversion of arable farmland to grassland and scrub habitats on Black Bourn Valley nature reserve in Suffolk (south-east England) 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 revealed statistical evidence that species diversity/richness and field grasshopper Chorthippus brunneus (Thunberg, 1815), meadow grasshopper Pseudochorthippus parallelus (Zetterstedt, 1821), common groundhopper Tetrix undulata (Sowerby, 1806) and slender groundhopper Tetrix subulata (Linnaeus, 1758) 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 favorable 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 (Agrostis and Festuca spp.) and a low abundance of leaf litter. Lagomorph grazing by wild brown hare Lepus europaeus and rabbit Oryctoloagus cuniculus was critical in maintaining exposed soil for Orthoptera in the older fields, while deer paths appeared to create microhabitats that may be utilized by Orthoptera. We postulate that rewilding schemes on arable farmland should use a Rewilding Max approach and avoid the frequent usage of domestic livestock, relying on wild lagomorph and ungulate grazers to maintain an open mosaic habitat structure with only intermittent cattle, horse, or sheep grazing.