Short-Term Livestock Grazing Exclusion Has No Site-Scale Impact on an Endangered Lizard

Abstract

Grasslands are among the most utilised habitat types for livestock production and the least protected ecosystems globally. Livestock grazing alters the abiotic and biotic features of a landscape and influences vegetation structure. In turn, these vegetation structural changes can adversely impact native animals that use these habitats, including reptiles. The endangered pygmy bluetongue lizard (Tiliqua adelaidensis) exclusively inhabits livestock-grazed grasslands in South Australia. Using a before/after, control/impact design, we investigated the effects of short-term grazing exclusion on vegetation structure and lizard abundance across two sites with natural vegetation and climate variation. We found vegetation structure differed between the two sites in “before” and “after” data but did not detect any effect of grazing treatment. We detected a negative association of lizard abundance with tussock cover in “before” data and a negative association with bare ground in the “after” data at the more arid site (Peterborough), although there was no significant overall grazing exclusion effect on lizard abundance at either site. Our survey techniques at a site scale may not have captured microhabitat-scale changes that could have influenced pygmy bluetongue responses. This study indicates short-term and small spatial scale grazing exclusion will have non-significant effects on pygmy bluetongues. Sheep grazing management is an important component of pygmy bluetongue conservation, and we recommend further research to incorporate multiple spatial scales over a longer time prior to applying landscape management actions.