Biodiversity benefits of vegetation restoration are undermined by livestock grazing

Abstract

Extensive areas of the Earth's terrestrial surface have been subject to restoration, but how best to manage such restored areas has received relatively limited attention. Here, we quantify the effects of livestock grazing on bird and reptile biota within 61 restoration plantings in south‐eastern Australia. Using path analysis, we identified some of the mechanisms giving rise to differences in patterns of species richness and individual species occurrence between grazed and ungrazed plantings. Specifically, we found evidence of both: (1) indirect effects of grazing on various elements of biodiversity mediated through changes in vegetation condition (primarily the leaf litter layer), and (2) direct effects of grazing on biodiversity (irrespective of modification in vegetation cover attributes), possibly as a result of trampling by livestock. We also uncovered evidence of direct effects on bird and reptile biota of other planting attributes such as planting width and planting age. The results of our study suggest that the biodiversity benefits of restoration programs can be undermined by grazing, especially by uncontrolled grazing. We suggest that where the objective of vegetation restoration is to enhance biodiversity conservation, grazing within plantings should be limited or excluded.