CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China; University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China.
Sci Total Environ. 2020 Jul 1;724:138267. doi: 10.1016/j.scitotenv.2020.138267. Epub 2020 Mar 27.
Successful re-establishment and maintenance of submerged macrophytes is a pivotal problem for the restoration of shallow eutrophic lakes, since submerged macrophytes can facilitate a shift of lake ecosystems from a turbid water state to a clear water state through their structuring roles. However, little is known about the optimal number of macrophyte species (species richness) needed for the recovery of shallow eutrophic lakes. Here, we investigated 19 shallow eutrophic lakes along the mid-lower reaches of the Yangtze River to reveal the underlying interrelations among water clarity, water quality and species richness. Our results showed positive correlations of water nutrients (TN and TP) with K and Red/Blue light ratio, suggesting that bad water quality can significantly lower water clarity. The results of path analysis indicated that the underwater light climate directly affects morphological and physiological traits and species richness of submerged macrophytes. Changes in functional traits also affected significantly the species richness of submerged macrophytes. Moreover, the presence of submerged macrophytes not only had positive effects on the underwater light climate (water clarity), but also on water quality. Most importantly, the assemblage of three or more submerged macrophyte species can significantly improve water clarity in these sampled eutrophic lakes, but not water quality. Additionally, the basic species assemblage of Myriophyllum spicatum and Vallisneria natans can be used for restoration of submerged macrophytes in shallow eutrophic Yangtze floodplain lakes. It is concluded that species richness and species assemblage are critical for recovery of submerged macrophytes in shallow eutrophic lakes.
成功重建和维持沉水植物是富营养化浅水湖泊恢复的关键问题，因为沉水植物可以通过其结构作用促进湖泊生态系统从浊水状态向清水状态的转变。然而，对于浅水富营养化湖泊恢复所需的沉水植物物种（物种丰富度）的最佳数量知之甚少。在这里，我们调查了长江中下游的 19 个浅水富营养化湖泊，以揭示水清晰度、水质和物种丰富度之间的潜在相互关系。我们的结果表明，水养分（TN 和 TP）与 K 和红/蓝光比呈正相关，表明水质差会显著降低水清晰度。路径分析的结果表明，水下光照条件直接影响沉水植物的形态和生理特征以及物种丰富度。功能特征的变化也显著影响沉水植物的物种丰富度。此外，沉水植物的存在不仅对水下光照条件（水清晰度）有积极影响，而且对水质也有积极影响。最重要的是，三种或更多沉水植物物种的组合可以显著提高这些富营养化湖泊的水清晰度，但不能提高水质。此外，菹草和苦草的基本物种组合可用于恢复长江泛滥平原浅水富营养化湖泊的沉水植物。结论是，物种丰富度和物种组合是浅水富营养化湖泊沉水植物恢复的关键。
