| 摘要: |
| 沉水植物是浅水湖泊生态系统的重要组成部分，其分布格局受环境因子特别是水深的影响；其次，不同水深梯度下影响沉水植物生长的关键因子也存在差异性，并与水深条件一起对沉水植物产生协同作用。本研究选取太湖东山湾这一太湖东部典型的草型湖区为研究区域，于2020年10月-2021年6月对东山湾31处不同水深的样点进行了3次水体理化指标与沉水植物种类及丰度的调查。采用单因素方差分析、Spearman相关性分析和冗余分析（RDA）方法对不同水深处沉水植物与环境因子的关系进行了显著性与相关性分析，确定了不同水深湖区中影响沉水植物群落组成的关键环境因子。结果表明：1）水体的物化指标表现出明显的时空差异。太湖东山湾近岸浅水区水体叶绿素a浓度（Chl.a）和透明度与水深之比（SD/WD）的均值显著高于近湖心较深的水域（P < 0.05）；春季水体总氮（TN）、硝态氮（NO3--N）、总磷（TP）、磷酸盐（SRP）和悬浮颗粒物（SS）浓度明显高于秋季和夏季。2）调查共记录到东山湾12个种类的沉水植物，中间水域的沉水植物频度更高，不同水深区域内的沉水植物群落表现出物种组成差异，竹叶眼子菜（Potamogeton wrightii/Potamogenton malaianus）、苦草（Vallisneria natans）和轮叶黑藻（Hydrilla verticillata）在近湖心区表现出更高的频度与丰度。3）影响东山湾沉水植物群落的关键水环境因子包括水深（WD）、TN、TP、SD/WD和Chl.a，且不同水深区域的沉水植物群落组成受到不同水环境因子调控。水深较浅的近岸区域影响沉水植物生长的关键环境因子包括WD和Chl.a；中间水域的沉水植物主要受到水体TN和TP的影响；而水深更深的近湖心区域则与WD、TN和TP显著相关。本研究结果为浅水湖泊水位管理以及不同水深环境下的沉水植物恢复提供了重要的理论依据。 |
| 关键词: 太湖，沉水植物群落，水深，限制因子 |
| DOI： |
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| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目），水深梯度下浅水湖泊稳态转换特征因子及其阈值研究 |
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| Difference on the limiting factors for submersed macrophyte occurrence along water depths in the Dongshan Bay of Taihu Lake |
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Chen Siwen,Jiang Lei,Ma Shuzhan,Wu Yue,Zhan Hongxin,Ye Qi,Chang Yiheng,Chen Kaining
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Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
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| Abstract: |
| Submersed plants are an integral component of shallow lake ecosystems, and their distribution patterns are influenced by environmental factors, particularly water depth. Key factors affecting the growth of submersed plants vary across different water depth gradients, and they interact synergistically with water depth conditions to influence submersed plant communities. Dongshan Bay, a typical grassy lake area in the eastern part of Lake Taihu, was selected as research area in this study. From October 2020 to June 2021, three surveys were conducted on water physicochemical indicators and the species richness and abundance of submersed plants at 31 sampling sites with varying water depths. Significance and correlation analyses of the relationship between submersed plants and environmental factors at different water depths were performed using one-way ANOVA, spearman correlation analysis, and redundancy analysis (RDA), identifying key environmental factors influencing submersed plant community composition in different water depth zones. The results indicate: 1) Physicochemical parameters of the water exhibited significant spatiotemporal differences. The average chlorophyll-a (Chl.a) content and the ratio of Secchi depth to water depth (SD/WD) in the nearshore waters of shallow areas in the Dongshan Bay of Lake Taihu were significantly higher than those in deeper near-lake center areas (P < 0.05). Total nitrogen (TN), nitrate nitrogen (NO3--N), total phosphorus (TP), phosphate (SRP) and suspended solids (SS) concentrations were significantly higher in spring than in autumn and summer. 2) This study recorded 12 species of submersed plants in Dongshan Bay, with higher frequency of submersed plants in the middle waters. The submersed plant communities in different water depth areas showed differences in species composition, with species like Potamogeton wrightii/Potamogenton malaianus, Vallisneria natans, and Hydrilla verticillata exhibiting higher frequency and abundance in the near-lake center area. 3) Key water environmental factors influencing the submersed plant community in Dongshan Bay include water depth (WD), TN, TP, SD/WD, and Chl.a, and the composition of submersed plant communities in different water depth areas is regulated by different water environmental factors. The key environmental factors affecting submersed plant growth in shallow nearshore areas include WD and Chl.a; submersed plants in the midwater area are mainly influenced by water TN and TP; while submerged plants in deeper areas near the lake center are significantly correlated with WD, TN and TP. The results of this study provide important theoretical basis for shallow lake water level management and submersed plant restoration under different water depth environments. |
| Key words: Taihu Lake submersed plant community water depth limiting factors |
