Mediterranean high mountain grasslands are shaped by climatic stress and understanding their functional adaptations can contribute to better understanding ecosystems’ response to global change. The present work analyses the plant functional traits of high-elevation grasslands growing in Mediterranean limestone mountains to explore, at the community level, the presence of different plant strategies for resource use (conservative vs. acquisitive) and functional diversity syndromes (convergent or divergent). Thus, we compared the functional composition and diversity of the above-ground traits related to resource acquisition strategies of subalpine and alpine calcareous grasslands in the central Apennines, a mountain region characterized by a dry-summer Mediterranean climate. We used georeferenced vegetation plots and field-measured plant functional traits (plant maximum height, specific leaf area and leaf dry matter content) for the dominant species of two characteristic vegetation types: the subalpine Sesleria juncifolia community and the alpine Silene acaulis community. Both communities are of particular conservation concern and are rich in endemic species for which plant functional traits are measured here for the first time. We analysed the functional composition and diversity using the community-weighted mean trait index and the functional diversity using Rao’s function, and we assessed how much the observed pattern deviated from a random distribution by calculating the respective standardized effect sizes. The results highlighted that an acquisitive resource use strategy and relatively higher functional diversity of leaf traits prevail in the alpine S. acaulis community, optimizing a rapid carbon gain, which would help overcome the constraints exerted by the short growing season. The divergent functional strategy underlines the co-occurrence of different leaf traits in the alpine grasslands, which shows good adaptation to a microhabitat-rich environment. Conversely, in the subalpine S. juncifolia grassland, a conservative resource use strategy and relatively lower functional diversity of the leaf traits are likely related to a high level resistance to aridity over a longer growing season. Our outcomes indicate the preadaptation strategy of the subalpine S. juncifolia grassland to shift upwards to the alpine zone that will become warmer and drier as a result of anthropogenic climate change.

中文翻译：

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亚平宁山脉亚高山和高山植被的叶性状功能组成和多样性

地中海高山草原受到气候压力的影响，了解它们的功能适应性可以有助于更好地了解生态系统对全球变化的反应。本工作分析了地中海石灰岩山区高海拔草地的植物功能性状，以在社区一级探讨资源利用（保守性与习性性）和功能多样性综合症（趋同或趋异）的不同植物策略的存在。 。因此，我们比较了亚平宁山脉中部亚高山和高山钙质草原资源获取策略相关的地上性状的功能组成和多样性，该山区以地中海夏季干燥为特征。结实的Sesleria juncifolia群落和高山的Sillene acaulis群落。这两个社区都特别关注保护问题，并且富含特有物种，首次在这里对它们的植物功能性状进行了测量。我们使用社区加权平均特征指数分析功能组成和多样性，并使用Rao函数分析功能多样性，并通过计算各自的标准化效应量来评估观察到的模式偏离随机分布的程度。结果表明，一种高采资源利用策略和相对较高的叶性状功能多样性普遍存在于高山金合欢中。社区，优化快速的碳吸收，这将有助于克服生长季节短带来的限制。不同的功能策略强调了高寒草原上不同叶片性状的同时存在，这表明它对富含微生境的环境具有良好的适应性。相反地​​，在亚高山准绳草草原上，保守的资源利用策略和相对较低的叶片性状功能多样性可能与更长的生长季节对干旱的高水平抗性有关。我们的研究结果表明，人为气候变化的结果表明，亚高山红松草草原的向上适应策略是向上转移至高山带，该高山带将变得更温暖，更干燥。