Understanding competitive interactions is essential to properly inform management strategies, in particular in the context of livestock-wildlife conflict across a degraded land, such as the case of wild guanacos in Patagonia. Guanacos are historically perceived by ranchers as livestock’s main competitors, and there is a growing demand for reducing their numbers. However, both competition theory and available evidence suggest a more complex interaction than the one assumed by the current management approach. This study aimed to test the occurrence of competitive exclusion of guanacos by domestic sheep at intra-ranch scale. We assessed the spatial segregation of guanacos and sheep and compared guanaco occupancy patterns within a sheep ranch with those recorded within an adjacent protected area free from livestock. The probability of a group of herbivores being sheep instead of guanacos increased in bottom valleys and smaller paddocks and decreased as the distance to water increased. These results agree with the expected patterns of sheep habitat use resulting from physiological restrictions and grazing behaviour. Occupancy patterns within the ranch showed a higher proportion of guanacos in ridges, away from water sources and in larger paddocks, opposing those observed in the sheep-free area where guanacos occupied mostly bottom valleys, irrespective of the distance to water. Areas used consistently by guanacos showed a higher per cent cover of preferred forage and basal-plant cover, indicating a better range condition than those used predominately by sheep. Our results add to the solid body of evidence on spatial segregation of these species at coarser spatial scales, support the competitive exclusion of guanacos by sheep and suggest that intra-ranch coexistence is possible because guanacos occupy areas underused or inaccessible to sheep. Under these conditions, it is unlikely that guanaco culling will improve sheep production and the empirical verification of the assumptions underlying current management initiatives becomes crucial.

中文翻译：

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牲畜-野生动物冲突背景下的竞争排斥和食草动物管理

了解竞争互动对于适当地为管理战略提供信息至关重要，特别是在退化土地上的牲畜与野生动物冲突的背景下，例如巴塔哥尼亚的野生原驼。从历史上看，原驼一直被牧场主视为牲畜的主要竞争对手，减少其数量的需求不断增长。然而，竞争理论和现有证据都表明，这种相互作用比当前管理方法所假设的更为复杂。本研究旨在测试牧场内家羊对原驼竞争排斥的发生情况。我们评估了原驼和绵羊的空间隔离，并将牧羊场内的原驼居住模式与相邻保护区内没有牲畜的情况进行了比较。在底部山谷和较小的围场中，一群食草动物是绵羊而不是原驼的概率随着与水的距离增加而降低。这些结果与生理限制和放牧行为导致的绵羊栖息地使用的预期模式一致。牧场内的居住模式显示，山脊、远离水源和较大的围场中的鬣蜥比例较高，与在无羊地区观察到的情况相反，在该地区观察到的鬣蜥主要占据底部山谷，而与水的距离无关。原驼一直使用的区域显示出较高的首选草料和基础植物覆盖率，表明比主要由绵羊使用的区域更好。我们的研究结果为这些物种在更粗略的空间尺度上的空间隔离提供了坚实的证据，支持绵羊对原驼的竞争排斥，并表明牧场内的共存是可能的，因为原驼占据了绵羊未充分利用或无法进入的区域。在这种情况下，猎杀原驼不太可能提高绵羊产量，对当前管理举措所依据的假设进行实证验证变得至关重要。