Habitat preference of the striped legless lizard: Implications of grazing by native herbivores and livestock for conservation of grassland biota

Résumé fourni par la source

Abstract Across the globe, many species of reptile are threatened with extinction, with changes in grazing pressure as a significant factor in their decline. Few studies have investigated the role of native herbivores, yet studying natural grazers may provide insight into natural grazing regimes, not apparent in studies of domestic livestock. In this study, we investigate the habitat requirements of a threatened Australian grassland reptile, the striped legless lizard,Delma impar, in grasslands grazed by a native herbivore, the eastern grey kangarooMacropus giganteus.Delma imparappears sensitive to habitat change resulting from altered grazing intensity, but a lack of information hinders implementation of appropriate grazing regimes. To address this gap, we investigated habitat preferences ofD. imparat multiple spatial scales across a grazing gradient. We found that the occurrence ofD. imparwas not affected by the size of grassland remnants, but was negatively related to the density of native grazers. This result was likely a consequence of the negative effect of high grazing intensity on grass structural complexity, as the probability of encountering aD. imparwas positively related to grass structural complexity at the fine scale (1 m2). We recommend that conservation efforts should avoid high intensity grazing (equivalent to > 1.3 kangaroos/ha), yet ensure enough grazing disturbance is maintained to promote the formation of complex grass structures. We also recommend that small floristically degraded and fragmented grassland habitat should be included in conservation efforts. These recommendations will likely benefit a number of faunal species in grasslands grazed by domestic and native grazers. Importantly, our data highlight the need for managing grazing regimes, even in environments dominated by native herbivores.

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