Mosses are a dominant ground cover in a wide array of ecosystems, especially in those developing under cold-stressed environments such as arctic and alpine ice-melting glacial forelands. Consequently, mosses may influence the performance and distribution of other plants. Here, we assessed the nature of interactions between vascular plants and cushion-forming mosses in three alpine communities in the northern Patagonian Andes. We recorded species richness, plant abundance and cover of vascular plants within and outside moss cushions, measuring also patch area and moss layer depth. To determine the effect of mosses on vascular plant assemblages, we calculated the relative interaction index (RII) in terms of richness, abundance and cover of all vascular plants, and of individual species. Moss-cushion patches showed higher species richness, plant abundance and cover in comparison with bare ground areas. Overall, the diversity of vascular plants increased with both moss-cushion area and layer depth. Species-specific RII values revealed that the effects of moss cushions on neighboring vascular plants were predominantly positive for all three plant communities surveyed. These results highlight the role of mosses as nurse plants in alpine ice-melting glacial forelands and, thus, as ecosystem engineers that can be key in maintaining vascular plant diversity.

中文翻译：

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高安第斯社区的垫层苔藓对维管束植物的促进作用

在广泛的生态系统中，尤其是在北极和高山冰融化的冰川前陆等寒冷环境下发展的生态系统中，苔藓是主要的地被植物。因此，苔藓可能会影响其他植物的性能和分布。在这里，我们评估了北巴塔哥尼亚安第斯山脉的三个高山社区中维管束植物与形成垫层的苔藓之间相互作用的性质。我们记录了苔藓垫子内外的物种丰富度，植物丰度和维管植物的覆盖率，还测量了斑块面积和苔藓层深度。为了确定苔藓对维管植物组合的影响，我们计算了所有维管植物以及单个物种的丰富度，丰度和覆盖度方面的相对相互作用指数（RII）。苔藓垫块显示出较高的物种丰富度，与裸露的地面相比，植物的丰度和覆盖度更高。总体而言，维管植物的多样性随着苔藓垫面积和层深度的增加而增加。特定物种的RII值表明，在所有接受调查的三个植物群落中，苔藓垫对邻近维管植物的影响主要呈阳性。这些结果突出了苔藓在高山冰融化的冰川前陆中作为养护植物的作用，因此，作为维持维管植物多样性的关键生态系统工程师。