State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, NO.866, Yuhangtang Road, Xihu District, Hangzhou, Zhejiang Province 310058, China.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2021 Feb 10;755(Pt 1):142479. doi: 10.1016/j.scitotenv.2020.142479. Epub 2020 Sep 25.
Dam operations can dramatically degenerate riparian vegetation. To improve the restoration practices of reservoir riparian vegetation, it is important to understand which and how a dominant species physiologically and ecologically maintain high fitness in this type of ecosystems. We explored the compositional change of riparian plants during the long-term flood-dry-flood cycle in the reservoir flood area (RFA) of the Three Gorges Reservoir Area (TGRA), China. In total 769 vascular plant species (belonging to 415 genera in 122 families) existed in the study area before damming (prior to 2006, i.e. the natural riparian zone). Following damming (2008-2018), plant species diversity rapidly declined, with only 51 species identified in 2018 (45 genera in 22 families). Before damming, perennial herbs, annual herbs and shrubs co-dominated the study area. After damming, the proportion of shrubs decreased significantly, and the proportion of annuals to total plants increased by 20%. Alien invasive species proportion increased from 5% to 18%. Notably, the proportion of C species increased significantly from 7% to 31%. Ten of the 16 dominant species in RFA since 2015 were C Poaceae species. Our study indicates that dam construction could cause severe biodiversity loss of riparian plants and draw alien species invasion. Besides, C herbs would dominate the RFA. A higher photosynthetic rate could help C plants grow faster to cope with the nitrogen deficiency and short growth cycles in RFA. Hence, screening C herbs for vegetation restoration might aid in maintaining biodiversity and ecosystem functions in flood-dry-flood reservoir flood areas.
水坝工程会显著破坏河岸植被。为了改善水库河岸植被的恢复实践，了解哪种和哪种优势物种在这种生态系统中具有较高的生理和生态适应性至关重要。我们在中国三峡库区水库洪水区（RFA）中探索了河岸植物在长期的洪水-干旱-洪水周期中的组成变化。在筑坝之前（2006 年之前，即自然河岸带），研究区域共有 769 种维管植物（属于 122 科 415 属）。筑坝后（2008-2018 年），植物物种多样性迅速下降，2018 年仅鉴定出 51 种（22 科 45 属）。筑坝前，多年生草本、一年生草本和灌木共同主导了研究区域。筑坝后，灌木的比例显著下降，一年生植物在总植物中的比例增加了 20%。外来入侵物种的比例从 5%增加到 18%。值得注意的是，C 类植物的比例从 7%显著增加到 31%。自 2015 年以来，RFA 的 16 种优势物种中有 10 种是 C 禾本科物种。我们的研究表明，水坝建设可能导致河岸植物的生物多样性严重丧失，并吸引外来物种的入侵。此外，C 类草本植物将主导 RFA。较高的光合速率可以帮助 C 类植物更快地生长，以应对 RFA 中的氮素缺乏和短生长周期。因此，筛选 C 类草本植物进行植被恢复可能有助于维持洪水-干旱-洪水水库洪水区的生物多样性和生态系统功能。
