Invertebrate communities occupying hypolithic habitats at the rock-soil interface are diverse and can contribute significantly to ecosystem functioning, especially in arid environments. However, these communities are poorly understood. We tested three hypotheses of processes that may structure these communities, these reflecting species-area relationships, microclimate refuges and the effects of predation. We quantified the communities and the microclimate occurring beneath rocks of varying sizes and the response of the communities to the presence of a rock turning predator (chacma baboon Papio ursinus) in the eastern Karoo, South Africa. The observed community comprised 44 morphospecies, representing 15 Orders, and the microclimate under the rocks was significantly ameliorated from the upper and lower extremes of temperature and consistently moister than the surrounding habitat. However, the species-area relationship, role of microclimate and the presence of baboons are weak predictors of this community structure. This may be due to these processes interacting in complex ways, and these hypolithic patches functioning as habitat refugia rather than as discrete islands. We argue that understanding the role of hypolithic patches as refugia is important, given that such refugia may provide for community stability in the face of climate change, which would be particularly important in harsh arid landscapes.

在岩石-土壤界面处占据次石器时代栖息地的无脊椎动物群落是多种多样的，并且可以极大地促进生态系统的功能，特别是在干旱环境中。但是，这些社区了解得很少。我们测试了可能构成这些群落的三个过程假说，这些假说反映了物种与地区的关系，小气候庇护所和捕食的影响。我们量化了在大小不同的岩石下发生的群落和微气候，以及群落对转石捕食者（chacma狒狒Papio ursinus）在南非东部的Karoo。观察到的群落包括44个形态科，代表15个阶，岩石下的微气候从温度的上下极端显着改善，并且始终比周围的栖息地湿润。但是，物种与区域的关系，小气候的作用以及狒狒的存在是该群落结构的较弱的预测指标。这可能是由于这些过程以复杂的方式相互作用，并且这些石器时代的斑块起着栖息地避难所的作用，而不是作为离散的岛屿。我们认为，理解下石器时代斑块作为避难所的作用很重要，因为面对气候变化，避难所可能为社区带来稳定，这在干旱的干旱地区尤为重要。