Initial impact of a soil disturbance technique (disc harrowing) on Orthoptera in a grass heath in Breckland, UK

Abstract

On a Breckland grass heath in eastern England, soil disturbance methods such as disc harrowing employed to benefit endangered plants such as tower mustard, Arabis glabra, could also create exposed ground for localized insects, specifically the mottled grasshopper, Myrmeleotettix maculatus. Orthoptera of disc-harrowed strips on a grass heath at Santon Warren in Norfolk, UK, were monitored in 2018 and 2019. Data analysis focused on two target species, field grasshopper, Chorthippus brunneus, and M. maculatus, which are likely to respond positively to the creation of early successional habitat. Of the two species, M. maculatus was found in significantly high abundance on the disc-harrowed strips, whereas C. brunneus was not. The species richness of Orthoptera did not appear affected by harrowing, although three species at this location (lesser marsh grasshopper, Chorthippus albomarginatus, long-winged conehead, Conocephalus fuscus, and Roesel’s bush-cricket, Roseliana roeselii) need taller vegetation than was present on the disc-harrowed strips.

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

“…As succession progresses on rewilded sites, the prevalence of ant hills should be monitored to ensure that this valuable resource for invertebrates persists. If there is a loss of bare earth on ant hills over time, then site managers could consider periodic rotovation of strips through fields for early successional, disturbance-dependent species (e.g., C. brunneus and groundhoppers), similar to the management of nearby Breckland heaths (Gardiner 2020). Any rotovation should be irregularly undertaken to avoid too much intervention in natural processes, akin to Rewilding Max.…”