Livestock grazing has been used for conservation management in some situations to reduce exotic plant cover, but supporting empirical evidence is scant. This is particularly true for eastern Australian semiarid woodlands and forests. We surveyed 451 sites across three broad semiarid vegetation communities (cypress pine, black box, red gum) in eastern Australia to examine the effects of recent and longer-term (historic) grazing by livestock on exotic (and native) plant cover. Because our focus was the use of domestic livestock for conservation management, our sites were mostly located in conservation reserves, travelling stock routes and native production forests where domestic grazing is approved via permit. We also included recent grazing by kangaroos and rabbits, which occur widely with livestock across the study sites. Structural equation modelling revealed that recent sheep and cattle grazing was associated with increased exotic plant cover in two of the three communities (cypress pine, black box), and historic grazing was associated with lower exotic (and native) plant cover across all communities. Recent cattle grazing-induced reductions in exotic plant cover in the red gum community resulted from declines in the palatable exotic annual grass Ehrharta longiflora. Higher intensity grazing by rabbits, sheep and cattle in the cypress pine community increased exotic plant cover by suppressing the negative effect of native cover on exotic cover. Higher intensity rabbit grazing reinforced the negative effect of nitrogen on native plant cover, resulting in increases in exotic cover. Overall, we found strong evidence that domestic livestock grazing reduces native plant cover either directly or indirectly in all three communities, but limited evidence that it would be a useful conservation management strategy to reduce exotic plant cover in these communities.

中文翻译：

---

使用牲畜进行外来植物覆盖保护管理的证据有限

在某些情况下，牲畜放牧已被用于保护管理，以减少外来植物的覆盖，但支持的经验证据很少。对于澳大利亚东部的半干旱林地和森林来说尤其如此。我们调查了澳大利亚东部三个广泛的半干旱植被群落（柏松、黑匣子、红胶）的 451 个地点，以检查最近和长期（历史）牲畜放牧对外来（和本地）植物覆盖的影响。由于我们的重点是使用家畜进行保护管理，因此我们的场地大多位于通过许可批准家畜放牧的保护区、游牧路线和本地生产林中。我们还包括最近袋鼠和兔子的放牧，这在整个研究地点与牲畜一起广泛发生。结构方程模型显示，最近的羊和牛放牧与三个社区中两个（柏松、黑匣子）的外来植物覆盖率增加有关，而历史放牧与所有社区的外来（和本地）植物覆盖率降低有关。最近牛放牧引起的红胶群落外来植物覆盖减少是由于可口的外来一年生草Ehrharta longiflora的减少。柏松群落中兔、羊和牛的高强度放牧通过抑制本地覆盖对外来覆盖的负面影响来增加外来植物覆盖。更高强度的兔子放牧加强了氮对本地植物覆盖的负面影响，导致外来植物覆盖增加。全面的，