| 澜沧江流域糯扎渡水库消落带植被的物种组成、空间分布特征及地形解释 |
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| 引用本文： | 江维薇,李文涛,肖衡林.澜沧江流域糯扎渡水库消落带植被的物种组成、空间分布特征及地形解释[J].湖泊科学,2022,34(6):2025-2038. |
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| 作者姓名： | 江维薇 李文涛 肖衡林 |
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| 作者单位： | 湖北工业大学土木建筑与环境学院, 武汉 430068 |
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| 基金项目： | 国家重点研发计划项目（2016YFC0502208）、湖北省自然科学基金项目（2020CFB409）、湖北省科技厅创新群体项目（2020CFA046）和国家自然科学基金项目（42101375，52078195）联合资助. |
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| 摘 要： | 澜沧江最大梯级水库——糯扎渡水库运行之后，消落带许多原有植被物种被淹消亡，造成大面积次生裸地以及严重水土流失现象.消落带植被亟待生态修复，但缺乏基本数据支撑和参考.2020年7月，基于轻型无人机支持下的3S技术，结合现场调研，采用神经网络模型、空间叠加分析、景观格局指数以及典型相关性分析等方法，提取了糯扎渡水库典型消落带植被分类图及地形数据，定量分析了研究区本土物种组成、面积、覆盖率、分布特征、景观空间格局及地形解释.结果显示，研究区消落带植被覆盖率达74.13%，涵盖18种植物，物种数量仅占蓄水前的18.9%，原生植物仅剩飞机草（Chromolaena odorata）存活，物种组成趋于简单，以一年生草本和多年生草本为主，分别占比55.56%、33.33%，菊科占据优势，苍耳（Xanthium sibiricum）、狗牙根（Cynodon dactylon）、牛筋草（Eleusine indica）和藿香蓟（Ageratum conyzoides）为主要优势物种，分别占比47.41%、29.39%、9.37%和4.56%，可作为生态修复备选物种.地形因子对消落带植被影响大小：高程>地表起伏度>水体距离>坡度>地形湿度指数>坡向.研究区优势植物均呈聚集分布，消落带中下部、上部分别以苍耳和狗牙根斑块为主导，苍耳和狗牙根在斑块优势度、连通性以及形状复杂性方面均远大于牛筋草和藿香蓟，表现出了较强的生存潜力.苍耳在地表起伏度0~1.26 m区段覆盖良好，狗牙根、牛筋草在地表起伏度0.78~2.07 m区段覆盖良好，当地表起伏度>2.07 m，植被生长困难.植被景观格局的破碎化程度、斑块形状复杂性分别与地表起伏度呈正相关、负相关，即地表起伏度越大导致植被景观格局越破碎和斑块形状越简单，进而导致种群生存力减弱.
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| 关 键 词： | 澜沧江流域 糯扎渡水库 无人机 消落带 植被 物种组成 空间分布 |
| 收稿时间： | 2021/9/8 0:00:00 |
| 修稿时间： | 2022/2/8 0:00:00 |
Species composition, spatial distribution characteristics and topographic attribution of vegetation in the water-level-fluctuating zone of the Nuozhadu Reservoir in the Lancang River Basin |
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| Jiang Weiwei,Li Wentao,Xiao Henglin.Species composition, spatial distribution characteristics and topographic attribution of vegetation in the water-level-fluctuating zone of the Nuozhadu Reservoir in the Lancang River Basin[J].Journal of Lake Science,2022,34(6):2025-2038. |
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| Authors: | Jiang Weiwei Li Wentao Xiao Henglin |
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| Institution: | School of Civil and Environment, Hubei Universal of Technology, Wuhan 430068, P. R. China |
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| Abstract: | After the operation of the Nuozhadu Reservoir, the largest cascade reservoir along the Lancang River, the original vegetation in the water-level-fluctuating zone (WLFZ) was inundated and extinguished, resulting in large areas of secondary bare ground and severe soil erosion. Ecological restoration of vegetation in the WLFZ is necessary but lacking basic data support and scientific reference. In this paper, based on 3S technology supported by light drones and combined with field research, a neural network model, spatial superposition analysis, landscape pattern index and typical correlation analysis were used to extract the vegetation classification map and topographic data of the typical WLFZ of the Nuozadu Reservoir in July 2020, and to intuitively and quantitatively analyze the native species composition, area, coverage, distribution characteristics along the terrain, landscape spatial pattern and their topographic attribution in the study area. The results showed that the vegetation coverage of the study area reached 74.13%, covering 18 species of plants, with the number of species only 18.9% of that before the construction of the reservoir. Only Chromolaena odorata (Chr) survived in the native plants. The species composition tended to be simple, with annual and perennial herbs dominating, accounting for 55.56% and 33.33% respectively, with Asteraceae as the dominant family, Xanthium sibiricum (Xan), Cynodon dactylon (Cyn), Eleusine indica (Ele) and Ageratum conyzoides (Age) were the dominant species, accounting for 47.41%, 29.39%, 9.37% and 4.56% respectively, and could be used as alternative species for restoration. The vegetation in the WLFZ was affected by topographic factors in the following order:elevation>surface fluctuation>nearest water distance>slope>topographic humidity index>slope direction. The dominant plants in the study area were all aggregated distributed, with patches of Xan and Cyn dominating the lower-middle part and upper part of the WLFZ respectively, with Xan and Cyn showing much greater patch dominance, connectivity and shape complexity than Ele and Age, showing a stronger potential for survival. Xan was well covered in the 0-1.26 m section of surface fluctuation, and Cyn and Ele were well covered in the 0.78-2.07 m section of surface fluctuation. When the surface fluctuation was >2.07 m, the vegetation growth was difficult. The degree of fragmentation of the vegetation landscape pattern and the complexity of the patch shape were positively and negatively correlated with the surface fluctuation respectively, i.e. the greater the surface fluctuation led to the more fragmented and simple shape of the vegetation landscape pattern, which in turn led to a reduction in the viability of the population. |
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| Keywords: | Lancang River Basin Nuozhadu Reservoir drone water-level-fluctuating zone (WLFZ) vegetation species composition spatial distribution |
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