Cushion plants are specialized keystone species of alpine environments that can have a positive effect on ecosystem structure and function. However, we know relatively little about how cushion plants regulate the diversity and composition of soil microbial communities, major drivers of soil processes and ecosystem functioning. Identifying what factors drive the diversity and composition of soil microbial communities in high-elevation ecosystems is also fundamental to predict how global changes will affect their conservation and the services and functions they provide. Thus, we sampled four sites along the southern Andes following the vegetation belt of Azorella cushion species. The field sites spread along a latitudinal gradient and had contrasting levels of aridity, UV-B radiation, mean temperature and soil properties. Overall, Azorella, as well as aridity and UV-B radiation, were the major drivers of the distribution, composition and diversity of soil microbial communities in the studied ecosystems of the Chilean Andes. UV-B radiation affected particularly soil fungi, while soil properties such as pH, total C and N content, essential predictors of microbial diversity globally, had a much lower effect on the composition of soil microbial communities. Understanding the factors driving the structure and composition of microbial communities, particularly the role of cushion plants and the feedbacks between plant, climate and soil is of uttermost importance for the preservation of the functionality of high-elevation ecosystems threatened by climate change.

垫层植物是高山环境中的重要基石种，可以对生态系统的结构和功能产生积极影响。但是，我们对垫层植物如何调节土壤微生物群落的多样性和组成，土壤过程和生态系统功能的主要驱动因素知之甚少。识别哪些因素会驱动高海拔生态系统中土壤微生物群落的多样性和组成，这对于预测全球变化将如何影响其保护及其提供的服务和功能也是至关重要的。因此，我们沿着安索斯山脉植被带沿安第斯山脉南部采样了四个地点坐垫种类。田间地点沿纬度梯度分布，并且具有不同程度的干旱，UV-B辐射，平均温度和土壤特性。总体而言，Azorella以及干旱和UV-B辐射是智利安第斯山脉研究生态系统中土壤微生物群落分布，组成和多样性的主要驱动力。UV-B辐射尤其影响土壤真菌，而土壤特性（例如pH值，总C和N含量）是全球微生物多样性的重要预测指标，对土壤微生物群落组成的影响要小得多。了解微生物群落结构和组成的驱动因素，特别是垫层植物的作用以及植物，气候和土壤之间的反馈，对于维护受到气候变化威胁的高海拔生态系统的功能至关重要。