Topographic heterogeneity influences diversity and abundance of Orthoptera in a rewilding scheme

Rewilding aims to restore ‘self-willed’ ecosystems involving the creation of habitats subject to stochastic disturbance connected by favorable corridors for dispersal of animals, including insects. Reversion of arable land to grassland and scrub habitats adjacent to Arger Fen nature reserve in Suffolk (southeast England) through non-intervention allowed succession to occur largely unmanaged on fields with differing topography, from flat terrain to slopes. Monitoring of Orthoptera revealed statistical evidence that species diversity and richness was greater on the steeper slopes (gradient > 10%), while species varied in their topographic preferences from flat terrain (e.g., long-winged conehead Conocephalus fuscus Fabricius, 1793) to slopes (e.g., field grasshopper Chorthippus brunneus Thunberg, 1815). Lagomorph grazing by the wild brown hare Lepus europaeus (Pallas, 1778) and the rabbit Oryctoloagus cuniculus (Linnaeus, 1758) appeared to be critical in maintaining exposed soil for hillside species such as C. brunneus , which may require the egg-laying and basking habitat. A mosaic of scrub and grassland on a wooded hillside affected by ash dieback Hymenoscyphus fraxineus (Baral et al. 2014) was also important for Orthoptera. We postulate that rewilding schemes on arable land may be particularly effective when there are topographic undulations incorporating flat and hillside areas to promote the greatest diversity of Orthoptera.