| 摘要: |
| 水生植被和藻华作为湖泊生态系统的主要初级生产者，对湖泊生态系统分别起着积极和消极的作用。在气候变化和人类活动双重作用下，湖泊富营养化加剧，水生植被退化，藻华频发。开展湖泊水生植被群落和藻华的长期观测可为湖泊生态系统水生植被修复和藻华管控提供决策依据。本研究以草型湖泊-长荡湖为研究区，基于1985-2021年的Landsat 5和8卫星数据，利用VBI（Vegetation and bloom indices）草藻分类算法，开展了浮叶/挺水植被、沉水植被和藻华长时序时空演变分析。结果表明：36年来，长荡湖总水生植被，浮叶/挺水植被和沉水植被都呈现显著下降趋势（p-value < 0.01），其中沉水植被下降趋势尤为明显，沉水植被从湖中心向岸边逐步退化，其覆盖度从1985年的75%下降至2021年的不足21%；自2011年起，长荡湖水生植被优势生活型从沉水植被转变为浮叶/挺水植被；2010年首次监测到藻华发生，2020年和2021年连续两年均监测到湖中心有大面积藻华暴发。基于湖泊围网面积和气象数据分析，发现围网拆除是水生植被退化和优势生活型转变的主要因素（R2 = 0.97，p-value < 0.01）。 |
| 关键词: 长荡湖 水生植被 藻华 围网 遥感 |
| DOI： |
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| 基金项目:国家自然科学基金面上项目“湖泊沉水植被区水体二氧化碳分压(pCO2)遥感估算研究” (42271377) |
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| Remote sensing monitoring of long-term spatiotemporal evolution of aquatic vegetation and algal blooms in Lake Changdang, Taihu basin (1985-2021) |
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Huang Linsheng1, Ni Guigao1, Wang Kang2, Zhao Jinling1, Luo Juhua3
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1.Anhui University;2.:Anhui University;3.Nanjing Institute of Geography and Limnology，Chinese Academy of Sciences
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| Abstract: |
| Aquatic vegetation and algal blooms play crucial roles as primary producers within lake ecosystems, exerting both positive and negative effects. However, the combined impacts of climate warming and intensified human activities have led to significant transformations in lakes, such as eutrophication, degradation of aquatic vegetation, and the occurrence of algal blooms. Long-term monitoring of aquatic vegetation communities and algal blooms in lakes is essential for informed decision-making on aquatic vegetation restoration and algal bloom control. This study focuses on long-term changes in aquatic vegetation communities and algal blooms in Changdang Lake. Based on Landsat 5 and 8 satellite data from 1985 to 2021, we employed the VBI algorithm, a classification algorithm capable of identifying aquatic vegetation and algal blooms, to analyze the temporal and spatial evolution of floating/emergent aquatic vegetation, submerged aquatic vegetation, and algal blooms. The findings reveal a significant decline (p-value < 0.01) in both floating leaf/emergent vegetation and submerged vegetation within Changdang Lake over the past 36 years. Specifically, submerged aquatic vegetation gradually degraded from the lake"s center towards the shore, with coverage decreasing from 75% in 1985 to less than 21% in 2021. Since 2011, the dominant aquatic vegetation community in Lake Changdang has transitioned from submerged vegetation to floating/emergent vegetation. Notably, the presence of algal blooms was first detected in 2010, with subsequent large-scale occurrences in the lake"s center observed in 2020 and 2021. Eutrophication and enclosure activities were identified as the primary factors contributing to the degradation of aquatic vegetation(R2 = 0.97, p-value <0.01). |
| Key words: Changdang Lake Aquatic vegetation Algal blooms enclosure aquaculture remote sensing. |
