Keystone plant species are known to provide various essential ecosystem services. The Mediterranean keystone species Stipa tenacissima improves soil functioning and facilitates the establishment of different plant species, so it is used in restoration programmes. In this paper, we aimed to predict the impacts of climate (aridity) and soil texture (sand content) on the establishment and development of S. tenacissima (number, cover and width of tussocks) and on soil properties underneath S. tenacissima tussocks. This research demonstrated a significant positive effect of S. tenacissima on LFA (landscape function analysis) indices, revealing the importance of this key species in the soil stabilization, water infiltration and nutrient cycling. Similarly, soil nutrient contents (organic carbon and total nitrogen) and enzyme activities (s-glucosidase and phosphatase) were highly improved underneath S. tenacissima compared to bare ground areas. However, increases of aridity and sand content showed strong negative effects on soil organic carbon, total nitrogen and activities of the hydrolytic enzymes both on bare ground areas and underneath S. tenacissima tussocks. Furthermore, we found that the climate is the main controller of the number of S. tenacissima tussocks, cover and width. Soil sand content influences the colonization of S. tenacissima, as it affects soil water potentials. In general, this study demonstrates the non-sustainability of S. tenacissima under a warmer and drier climate, which will negatively affect its ability to create islands of fertility in South Mediterranean grasslands.

中文翻译：

---

气候变化对地中海关键植物物种的预测影响

众所周知，关键植物物种可提供各种基本的生态系统服务。地中海关键物种 Stipa tenacissima 改善了土壤功能并促进了不同植物物种的建立，因此它被用于恢复计划。在本文中，我们旨在预测气候（干旱）和土壤质地（含沙量）对 S. tenacissima 的建立和发展（草丛的数量、覆盖度和宽度）以及对 S. tenacissima 草丛下土壤性质的影响。这项研究证明了 S. tenacissima 对 LFA（景观功能分析）指数的显着积极影响，揭示了这一关键物种在土壤稳定、水分渗透和养分循环中的重要性。相似地，与裸露地面相比，S. tenacissima 下的土壤养分含量（有机碳和总氮）和酶活性（s-葡萄糖苷酶和磷酸酶）得到了极大改善。然而，干旱度和含沙量的增加对裸地和草丛下的土壤有机碳、总氮和水解酶的活性有强烈的负面影响。此外，我们发现气候是S. tenacissima 丛生数量、盖度和宽度的主要控制者。土壤砂含量影响 S. tenacissima 的定植，因为它影响土壤水势。总的来说，这项研究表明 S. tenacissima 在更温暖和更干燥的气候下是不可持续的，这将对其在南地中海草原上创造肥沃岛屿的能力产生负面影响。