Potential Benefit of Predator Exclusion Fence for the Threatened Ground Wētā <i>Hemiandrus fabella</i>

Although conservation practitioners in Aotearoa New Zealand are world‐leaders in predator exclusion fencing for threatened species conservation, the degree to which fences protect invertebrates has not been extensively studied, especially in non‐forested environments. This study examines the potential impact of a predator exclusion fence on the threatened Tekapo ground wētā ( Hemiandrus fabella ) in a dryland environment. A mark‐recapture study was conducted to compare wētā relative abundance, sex ratios, size, and microhabitat associations inside and outside a predator exclusion fence. Wētā captures were 4.8 times higher inside the fence. Females accounted for approximately 67% of wētā both inside and outside the fence and were larger inside the fence. Wētā captures were higher in pitfalls situated in open microhabitats dominated by mat cover plants compared to microhabitats dominated by grasses. Overall, the predator exclusion fence appears to have had a significant positive impact on the H. fabella population; however, this result is strictly correlative because no population data was collected before the fence was installed. We hypothesise that the predator exclusion fence has increased the wētā population within by excluding hedgehogs ( Erinaceus europaeus ) which are considered a key predator of the species. We discuss evidence for and against this mechanism as a driver of wētā population density and what future work is required to confirm our hypothesis.