| 摘要: |
| 恢复沉水植被是城市富营养化湖泊生态修复的重要手段，了解沉水植物的生境需求是实现沉水植被有效恢复的重要基础。为探讨亚热带城市湖泊中沉水植物的生境需求，本研究选择武汉东湖、南湖和沙湖开展野外调查，以优势物种密刺苦草（Vallisneria denseserrulata Makino）为研究对象。研究测定了植物中长期生长（如生物量）、短期生理（如碳水化合物含量）以及瞬时荧光等16个指标以及水体和底泥相关性质等17个指标，通过结合广义加性模型（GAM）和植物性状网络分析（PTN）综合判断密刺苦草在武汉城市湖泊中的生境需求范围。结果表明：（1）3个城市湖泊的43个采样点中53.5%处于轻度富营养化，46.5%处于中度富营养化；（2）环境对密刺苦草生物量积累的影响比较显著。水深约1.1 m及水体总氮浓度约1 mg/L等条件最有利于密刺苦草的生长和生物量积累。底泥总氮在0.16~2.5 g/kg以及底泥TOC在0.19%~13.70%的范围内会促进密刺苦草生物量的增加；（3）密刺苦草组织内的N:P比（平均值：3）表现出密刺苦草受环境养分中的N限制。GAM结果表明密刺苦草的生长受水体总磷以及底泥总磷的影响很小，城市湖泊中的氮源对密刺苦草的重要性要大于磷源；（4）较高的水体营养水平往往会促进密刺苦草的短期碳氮代谢，抑制密刺苦草的生长。而底泥有机碳含量对密刺苦草生长和繁殖的负面效应较弱。研究认为，未来在应用密刺苦草对亚热带城市湖泊进行修复时，需要更关注对水体生境条件的控制，尤其是氮源，从而最大化其生态效益，更有效地促进湖泊生态修复。 |
| 关键词: 武汉城市湖泊 密刺苦草 生态修复 生境需求 富营养化 |
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| Habitat requirements analysis of Vallisneria denseserrulata Makino in the lake restoration of typical subtropical city (Wuhan) |
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Yin Jinfeng1, Cao Yu2, Lv Chaochao3, Cao Te3, Zhang Yuan, Zhang Yicheng, Qin Jing, Tang Xin3
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1.Institute of Hydrobiology, Chinese Academy of Sciences;2.Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garde, Chinese Academy of Sciences;3.Institute of Hydrobiology
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| Abstract: |
| The restoration of submerged vegetation plays an important role in the ecological restoration of eutrophic urban lakes, and the study on the habitat requirements of submerged vegetation is essential for the effective restoration of them. In order to investigate the habitat requirements of submerged macrophytes in subtropical urban lakes in China, three typical urban lakes in Wuhan, namely Donghu Lake, Nanhu Lake and Shahu Lake, were selected for field investigation in this study. Vallisneria denseserrulata Makino, a dominant species, was selected as the research object. The study measured 16 indicators of V. denseserrulata Makino including medium to long-term growth (e.g. biomass), short-term physiology (e.g. carbohydrate content), and instantaneous fluorescence, along with 17 indicators related to water and sediment properties. By integrating generalized additive models (GAM) and plant trait network analysis (PTN), the study comprehensively assessed the habitat requirements of V. denseserrulata Makino in urban lakes of Wuhan. Results showed that: (1) 53.5% of the 43 sampled sites in three urban lakes are mildly eutrophic, while 46.5% are moderately eutrophic. (2) Environmental factors significantly affect the biomass accumulation of V. denseserrulata Makino. Conditions such as a water depth of approximately 1.1 m and a total nitrogen concentration of around 1 mg/L are most favorable for the growth and biomass accumulation of V. denseserrulata Makino. Total nitrogen in the sediment ranging from 0.16 to 2.5 mg/kg and total organic carbon (TOC) in the sediment from 0.19% to 13.70% can promote biomass increase; (3) The N:P ratio (average: 3) in V. denseserrulata Makino tissue indicates that its growth is limited by nitrogen in the environmental nutrients. GAM analysis shows that the growth of V. denseserrulata Makino is minimally affected by total phosphorus in the water and sediment, and that nitrogen sources in urban lakes are more important to V. denseserrulata Makino than phosphorus sources; (4) Higher nutrient levels in the water often stimulate the short-term carbon and nitrogen metabolism of V. denseserrulata Makino, but inhibit its long-term growth. The negative effect of sediment organic carbon content on the growth and reproduction of V. denseserrulata Makino is relatively weak. The research suggests that in the future, when applying V. denseserrulata Makino for the restoration of subtropical urban lakes, there should be a greater focus on controlling the habitat conditions of the water, especially nitrogen sources, in order to maximize its ecological benefits and more effectively promote lake ecological restoration. |
| Key words: Urban lake in Wuhan V. denseserrulata Makino Ecological restoration Habitat requirements Eutrophication |
