Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China; Fukang Station of Desert Ecology, Chinese Academy of Sciences, Fukang, China; University of Chinese Academy of Sciences, Beijing, China.
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China; Department of Crop and Forest Sciences & Agrotecnio Center, Universitat de Lleida, Lleida, Spain.
Sci Total Environ. 2020 May 15;717:137251. doi: 10.1016/j.scitotenv.2020.137251. Epub 2020 Feb 11.
Extreme climatic conditions are major drivers of ecosystem function and dynamics and their frequency is increasing under climate change. Climatic conditions interact with local microtopography, which might either buffer or exacerbate the degree of climatic stress. Here we sought to understand how extremely dry growing seasons affected the composition and productivity of desert ephemeral communities growing in sand dunes from the Gurbantunggut desert in Central Asia, and to which extent did microtopography modulate the response. We set up a rainfall manipulation study on four sand dune microtopographies and, during two consecutive years, we measured soil moisture, nutrients and texture, ephemeral layer composition, plant phenology, biomass accumulation and biomass allocation patterns for the dominant species. We observed significant biomass reductions during the extreme drought but plant community richness and composition were not affected, indicating that the composition of the ephemeral layer in this desert ecosystem may resist under extreme conditions. Additionally, extreme drought increased biomass allocation to reproductive organs of the dominant species. There were also significant microtopographic effects as the sensitivity of biomass to drought in western aspects was larger than in eastern aspects. Our results indicate that previously overlooked microtopographical differences may mediate the impact of climate change on plant communities.
极端气候条件是生态系统功能和动态的主要驱动因素，在气候变化下，其发生频率正在增加。气候条件与局部微地形相互作用，微地形可能缓冲或加剧气候胁迫的程度。在这里，我们试图了解极端干旱的生长季节如何影响中亚古尔班通古特沙漠沙丘上生长的荒漠短命植物群落的组成和生产力，以及微地形在多大程度上调节了这种响应。我们在四个沙丘微地形上设置了降雨控制实验，并在连续两年的时间里，测量了土壤水分、养分和质地、短命层的组成、植物物候、生物量积累和优势物种的生物量分配模式。我们观察到极端干旱期间生物量显著减少，但植物群落的丰富度和组成没有受到影响，这表明该沙漠生态系统的短命层组成可能在极端条件下具有抵抗力。此外，极端干旱增加了优势物种生殖器官的生物量分配。微地形也有显著的影响，因为西部方面的生物量对干旱的敏感性大于东部方面。我们的研究结果表明，以前被忽视的微地形差异可能会调节气候变化对植物群落的影响。
