Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China.
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, China.
Sci Total Environ. 2022 Nov 1;845:157137. doi: 10.1016/j.scitotenv.2022.157137. Epub 2022 Jul 6.
Hydropeaking has become a global issue because of extensive hydropower dam construction worldwide. Yet, its ecological impacts on riverine ecosystems are not well studied. We explored the effects of hydropeaking on riverine plants, based on data from a ~300 km reach downstream of the world's largest hydropower dam, the Three Gorges Dam. We tested three hypotheses relating to hydropeaking impacts on species elevational distributions, assemblage structure and species-specific biomass patterns by generalized linear mixed modelling and joint species distribution modelling. We found that, first, hydropeaking greatly shaped species elevational ranges, leading to expansions of herbs to high elevations and shifting species dominance at low elevations. Secondly, we detected contrasting effects of hydropeaking on assemblage-level characteristics of herbs. The inundation induced by hydropeaking had strong effects on assemblage composition and biomass allocation, where more biomass was allocated to belowground part. Hydropeaking blurred the species richness-biomass relationship, although it had little effect on species richness or plot-level biomass. Thirdly, hydropeaking induced inundation was the most important covariate driving species biomass patterns of riverine plants, although complex species-specific effects were identified, and random effects were often large in fitted models. We concluded that hydropeaking likely acted as a major driver of plant community assembly in rivers with a hydropower dam. Conservation and restoration of riverine plants can benefit from the inclusion of water level management in operational schemes of hydropower dams, especially during the early life history stages.
由于全球范围内广泛建设水力发电大坝，水跃现象已成为一个全球性问题。然而，其对河流生态系统的生态影响尚未得到充分研究。我们基于世界上最大的水力发电大坝三峡大坝下游约 300 公里的河道数据，探讨了水跃现象对河流植物的影响。我们通过广义线性混合模型和联合物种分布模型测试了三个与水跃现象对物种海拔分布、组合结构和物种特定生物量模式的影响相关的假设。我们发现，首先，水跃现象极大地塑造了物种的海拔范围，导致草本植物向高海拔扩展，并在低海拔地区改变了物种优势。其次，我们检测到水跃现象对草本植物组合水平特征的相反影响。水跃现象引起的淹没对组合组成和生物量分配有强烈影响，更多的生物量分配到地下部分。水跃现象模糊了物种丰富度与生物量之间的关系，尽管它对物种丰富度或样地水平的生物量几乎没有影响。第三，水跃现象引起的淹没是驱动河流植物物种生物量模式的最重要协变量，尽管存在复杂的特定物种效应，并且拟合模型中的随机效应通常较大。我们得出结论，水跃现象可能是水力发电大坝河流植物群落组装的主要驱动因素。在水力发电大坝的运营计划中，特别是在早期生命史阶段，纳入水位管理可以使河流植物的保护和恢复受益。
