| 引用本文: | 高弋明,殷春雨,刘霞,赵钰,陈非洲,陈新芳,关保华.抚仙湖近60年来沉水植物群落变化趋势分析.湖泊科学,2021,33(4):1209-1219. DOI:10.18307/2021.0421 |
| Gao Yiming,Yin Chunyu,Liu Xia,Zhao Yu,Chen Feizhou,Chen Xinfang,Guan Baohua.Changes of submerged macrophytes community in Lake Fuxian since 1960s. J. Lake Sci.2021,33(4):1209-1219. DOI:10.18307/2021.0421 |
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| 抚仙湖近60年来沉水植物群落变化趋势分析 |
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高弋明1,2, 殷春雨1, 刘霞1, 赵钰1, 陈非洲1,3, 陈新芳4, 关保华1,3
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1.中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室, 南京 210008;2.武汉市规划设计有限公司, 武汉 430000;3.中国科学院大学中国-丹麦科教中心, 北京 100049;4.河海大学水文水资源学院, 南京 210098
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| 摘要: |
| 自1960s以来，抚仙湖沿岸带沉水植物群落发展迅速，而监测频率相对不足.为了解抚仙湖沉水植物群落现状及过去60年内的变化趋势，于2016年7月，对抚仙湖全湖沉水植物进行调查，并结合以往多次调查数据进行趋势分析.本次调查设置了36条样带共41个样点.在实测数据验证后，使用卫星多光谱相机数据基于归一化植被指数（NDVI）计算全湖沉水植物分布面积.此外，计算了物种在沿岸带植被区的平均生物量、优势度和群落多样性指数.结果表明：抚仙湖沉水植物2016年夏季分布面积为5.14 km2，平均生物量（鲜重）密度为9.8 kg/m2，最高48.7 kg/m2，全湖总现存量（鲜重）5.02×104 t；共采集到沉水植物13种（类），隶属于5科6属.其中，生物量最高的物种是金鱼藻（Ceratophyllum demersum），其次是黑藻（Hydrilla verticillata）和穗花狐尾藻（Myriophyllum spicatum）；出现频度最高的物种是穗花狐尾藻，其次是苦草（Vallisneria natans）和篦齿眼子菜（Potamogeton pectinatus）；物种优势度最大的物种是穗花狐尾藻，其次是金鱼藻和黑藻；抚仙湖各样点沉水植物香农-威纳多样性指数介于0.05~1.28之间，全湖平均值为0.75；除轮藻类外，沉水植物群丛的冠层在1.5~4 m之间，其中金鱼藻群丛冠层最高.丝状附着藻大量出现，附着在高大的沉水植物冠层上的生物量远远多于附着在基质上的；丝状附着藻主要附着在群落上层沉水植物100 cm以内的植冠上.在过去的60年来，抚仙湖沉水植物分布面积、全湖总生物量和物种丰富度呈增加的趋势；低矮的草甸型物种如轮藻类、苦草等优势度下降，高大的冠层型沉水植物如穗花狐尾藻、金鱼藻等成为优势种；外来物种伊乐藻在最近几年出现并成为次优势种；丝状附着藻生物量增加.以上结果表明，目前抚仙湖沉水植物群落处于生物量、分布面积和多样性最高的阶段，是维持和保护的关键时期.但相比于国外类似湖泊，抚仙湖沉水植物丰富度一直较低，目前冠层型植物占优势、外来物种快速发展和丝状附着藻增殖的态势，将会引起群落结构不稳定，如果不加以保护和管理，可能会朝着富营养化湖泊的群落结构方向发展，进而对沿岸带水质产生不利影响.除了进一步控制抚仙湖入湖营养负荷外，我们建议对群落上层高大的冠层型沉水植物进行收割，收割深度为100 cm，从而控制冠层型沉水植物以及附着在其上的丝状附着藻，为草甸型沉水植物的发展创造条件，引导抚仙湖沉水植物群落向贫营养化湖泊的群落结构方向发展，但其可行性尚需开展研究. |
| 关键词: 贫营养深水湖泊 沉水植物 群落结构 外来物种 丝状附着藻 抚仙湖 归一化植被指数NDVI |
| DOI：10.18307/2021.0421 |
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| 基金项目:国家自然科学基金项目（31930074）和中国科学院南京地理与湖泊研究所自主部署项目（NIGLAS2016QY04）联合资助. |
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| Changes of submerged macrophytes community in Lake Fuxian since 1960s |
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Gao Yiming1,2, Yin Chunyu1, Liu Xia1, Zhao Yu1, Chen Feizhou1,3, Chen Xinfang4, Guan Baohua1,3
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1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.Wuhan Planning and Design Co., LTD., Wuhan 430000, P. R. China;3.Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing 100049, P. R. China;4.Hydrology and Water Resources College, Hohai University, Nanjing 210098, P. R. China
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| Abstract: |
| The submerged macrophyte communities have developed rapidly in the littoral zone of Lake Fuxian since 1960s, however, the monitoring frequency is relatively insufficient. To understand the distribution status and community changes of submerged macrophytes in Lake Fuxian during the past 60 years, we investigated and sampled the whole-lake submerged macrophytes and epiphytic filamentous algae from 41 sample sites in July 2016. The distribution of submerged macrophytes in the whole lake was determined by CBERS 04-based normalized difference vegetation index (NDVI) of August 18, 2016. In addition, the average biomass density, dominance index and the Shannon-Wiener diversity index in the coastal vegetation area were calculated. The results showed that the distribution area of submerged macrophytes in the summer of 2016 was 5.14 km2. The average biomass (fresh weight) density was 9.8 kg/m2, and the highest value was 48.7 kg/m2. The total biomass (fresh weight) of the submerged macrophytes in the whole littoral zone was 5.02×104 t. Totally 13 species of submerged macrophytes were collected, belonging to 5 families and 6 genera. Among the species, Ceratophyllum demersum had the highest biomass density, followed by Hydrilla verticillata and Myriophyllum spicatum. The species with the highest frequency of occurrence were M. spicatum, followed by Vallisneria natans and Potamogeton pectinatus. In addition, the species with the greatest dominance were M. spicatum, followed by C. demersum and H. verticillata. The Shannon-Wiener diversity index of submerged macrophytes in Lake Fuxian was between 0.05 and 1.28, having an average value of 0.75. Except for charophytes, the canopy of higher plant groups ranged from 1.5 m to 4 m, with the highest canopy of C. demersum. The biomass of epiphytic filamentous algae attached to the canopy of submerged macrophytes was much higher than that attached to the substrates, and filamentous algae mainly attached to the canopy of submerged plants within 100 cm along apical height. The historical data showed that the distribution area, total biomass and species richness of submerged macrophytes in Lake Fuxian increased sharply since 1957. The dominance of low meadow-forming species, such as charophytes and V. natans declined in recent years. In contrast, the tall canopy-forming submerged macrophytes such as M. spicatum and C. demersum dominated the community. The exotic species Elodea nuttallii emerged in recent years and became subdominant species. The epiphytic filamentous algae boosted, and most of them attached on the canopy of submerged macrophytes. At present, the submerged plant community in Lake Fuxian is at the highest stage of biomass, distribution area and diversity, which is the key period for protecting and maintaining the submerged macrophyte bed in the littoral zone. While, the dominance of tall canopy-forming species, the fast development of the exotic species and the bloom of the epiphytic filamentous algae may lead the submerged macrophytes community toward a structure composition which is common in eutrophic lakes. Therefore, it is urgent to control the nutrient loadings in Lake Fuxian and to harvest the upper crown within 100 cm of the tall species to control both the canopy-forming submerged macrophytes and the filamentous algae attached to them. These measures will create conditions for the development of the meadow-forming species and maintain the macrophytes community composition in oligotrophic lakes. |
| Key words: Deep oligotrophic lake submerged macrophytes community structure exotic species epiphytic filamentous algae Lake Fuxian normalized difference vegetation index (NDVI) |
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