Abstract Ants are one of the most abundant and ubiquitous organisms on Earth and play critical roles in multiple ecosystem services such as seed dispersal and nutrient cycling. Despite this, the effects of climatic and land use stressors on particular species or groups of ants are poorly known. We conducted a regional field survey across 108 locations in south-eastern Australia, using correlation network analysis and structural equation modelling to identify how ants respond to environmental stressors. We found contrasting relationships among ants, and aridity, vertebrate grazing intensity and history. Increasing aridity was associated with reduced ant richness, whereas increasing grazing intensity was associated with greater ant richness directly, and indirectly, via reductions in litter depth and perennial grass density. However, these taxonomically diverse groups of ant species still shared contrasting responses to increasing aridity and grazing intensity. We found strong associations between grazing, aridity and the abundance of Seed Harvesters, weak indirect relationships with Generalist Foragers, but no relationships for Predators or Sugar Feeders. Taken together, our work identifies contrasting relationships among grazing, aridity and ants (ant ‘winners’ or ‘losers’) across contrasting ecological contexts. Given that increasing aridity is generally associated with lower grazing intensity, our results suggest that locations with more arid sites will have lower ant richness with fewer Seed Harvesters, whereas more mesic sites with high grazing intensity might increase ant richness, and the abundance of specific ant species. Such knowledge is important if we are to maintain critical ant-mediated functions as Earth becomes drier and grazing intensity increases.

中文翻译：

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放牧和干旱对蚂蚁的功能和分类多样性有不同的影响

摘要 蚂蚁是地球上最丰富、最普遍的生物之一，在种子传播和养分循环等多种生态系统服务中发挥着关键作用。尽管如此，气候和土地利用压力因素对特定蚂蚁物种或群体的影响却鲜为人知。我们在澳大利亚东南部的 108 个地点进行了区域实地调查，使用相关网络分析和结构方程模型来确定蚂蚁如何应对环境压力。我们发现了蚂蚁、干旱、脊椎动物放牧强度和历史之间的对比关系。干旱增加与蚂蚁丰富度降低有关，而放牧强度增加与通过凋落物深度和多年生草密度减少直接或间接地增加蚂蚁丰富度有关。然而，这些分类学上不同的蚂蚁物种群体仍然对日益增加的干旱和放牧强度有不同的反应。我们发现放牧、干旱和种子收割机的数量之间存在很强的关联，与通才觅食者的间接关系较弱，但与捕食者或食糖者没有关系。总之，我们的工作确定了不同生态环境中放牧、干旱和蚂蚁（蚂蚁“赢家”或“输家”）之间的对比关系。鉴于干旱程度的增加通常与较低的放牧强度有关，我们的研究结果表明，干旱地点越多，种子收割机越少，蚂蚁丰富度越低，而放牧强度高的中性地点越多，蚂蚁丰富度和特定蚂蚁的丰度可能会增加。物种。