BACKGROUND Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant communities in the Maritime Antarctic region (cryptogams only) and the Falkland Islands (vascular plants only). We compared communities from the Falkland Islands (51 degrees S, mean annual temperature 7.9 degrees C), with those of Signy Island (60 degrees S, -2.1 degrees C) and Anchorage Island (67 degrees S, -2.6 degrees C), and experimental temperature manipulations at each of the three islands using Open Top Chambers (OTCs). RESULTS Despite the strong difference in plant growth form dominance between the Falkland Islands and the Maritime Antarctic, communities across the gradient did not differ in total diversity and species number. During the summer months, the experimental temperature increase at 5 cm height in the vegetation was similar between the locations (0.7 degrees C across the study). In general, the response to this experimental warming was low. Total lichen cover showed a non-significant decreasing trend at Signy Island (p < 0.06). In the grass community at the Falkland Islands total vegetation cover decreased more in the OTCs than in adjacent control plots, and two species disappeared within the OTCs after only two years. This was most likely a combined consequence of a previous dry summer and the increase in temperature caused by the OTCs. CONCLUSION These results suggest that small temperature increases may rapidly lead to decreased soil moisture, resulting in more stressful conditions for plants. The more open plant communities (grass and lichen) appeared more negatively affected by such changes than dense communities (dwarf shrub and moss).

中文翻译：

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环境变化对福克兰群岛和海洋南极的维管植物和密码藻群落的影响。

背景南极陆地植被受到地球上最极端气候之一的影响。目前，南极洲的部分地区是地球上变暖速度最快的地区之一。在 3 个生长季节期间，我们研究了实验性变暖对南极海上地区（仅隐花）和福克兰群岛（仅维管植物）沿海植物群落多样性和丰度的影响。我们比较了福克兰群岛（51 摄氏度，年平均气温 7.9 摄氏度）、西尼岛（60 摄氏度，-2.1 摄氏度）和安克雷奇岛（67 摄氏度，-2.6 摄氏度）的社区，以及使用开顶室 (OTC) 在三个岛中的每一个岛进行实验温度控制。结果 尽管福克兰群岛和海洋南极之间的植物生长形式优势存在很大差异，但整个梯度的群落在总多样性和物种数量方面没有差异。在夏季，植被中 5 厘米高度的实验温度升高在不同位置之间相似（整个研究为 0.7 摄氏度）。一般来说，对这种实验性变暖的反应很低。西尼岛的地衣总覆盖率呈非显着下降趋势（p < 0.06）。在福克兰群岛的草群落中，OTCs 的总植被覆盖率比相邻的对照样地减少得更多，仅两年后，OTCs 内的两个物种就消失了。这很可能是之前干燥的夏季和非处方药引起的温度升高的综合结果。结论 这些结果表明，温度的小幅上升可能会迅速导致土壤水分减少，从而对植物造成更大的压力。较开放的植物群落（草和地衣）似乎比密集的群落（矮灌木和苔藓）更受此类变化的负面影响。