Passive recovery of small vertebrates following livestock removal in the Australian rangelands

Abstract

AbstractIn arid environments, grazing by exotic herbivores, including domestic livestock, can greatly influence native, small vertebrate assemblages. Whether the removal of livestock facilitates passive recovery of these assemblages depends on habitat condition and the species present. We explore changes in small mammal and reptile species richness, abundance, and composition in a degraded chenopod shrubland dominated by Acacia victoriae ssp. and open Acacia aneura (mulga) woodland destocked in 1976 and 1984, respectively. Data were obtained between 1997 and 2007, from two grazed and two ungrazed sites in each community. Species richness increased at a faster rate in ungrazed open A. aneura woodland, but did not differ significantly between ungrazed and grazed degraded chenopod shrubland. Subsequent analyses at a finer‐scale detected disparate responses in richness and abundance for microhabitat. At this scale, a greater number of species‐specific responses were also detected, including increased abundance of generalist species and decreased abundance of species requiring low cover. These results reiterate the potential for species‐specific responses to livestock that are more apparent in particular microhabitats. Furthermore, this investigation provides evidence for the gradual passive recovery of small mammal and reptile assemblages in both communities, which is facilitated by the removal of livestock in open A. aneura woodland in fair condition, but not degraded chenopod shrubland in poor condition.