基于GIS与RS的楠溪江流域生态健康评估

发布时间：2018-03-12 14:31

本文选题：生态系统健康　切入点：流域　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：流域是人类与其他动植物生活的重要来源,在我国社会经济可持续发展的过程中,流域生态系统的好坏已经跃居成不可忽视的制约因素。通过对楠溪江流域生态系统健康进行评价,旨在为楠溪江流域的经济发展和环境的协调可持续发展提供科学的决策依据。首先,结合RS与GIS技术,对楠溪江流域生态系统构成现状及类型变化进行分析,并参考环保部《流域生态系统健康评价技术指南》,构建了陆域和水域的评价指标体系,其中,陆域包括陆域生态格局、陆域生态功能和陆域生态压力共三类九项指标,水域包括水域生境结构、水生生物和水域生态压力共三类七项指标,对楠溪江流域18个评价单元进行生态系统健康评价,并分析流域存在的主要问题。研究结论包括:①2014年,楠溪江流域生态系统以森林为主,所占比例为82.99%,其次是农田、城镇、湿地类型,所占比例分别为7.96%、4.90%和3.43%。②2000-2014年,楠溪江流域农田-森林和农田-城镇转移面积分别为59.35km~2和42.14km~2,两者合计占生态系统转换总面积的56.29%,生态系统类型转换主要发生在农田、森林和城镇之间。十四年间,楠溪江流域城镇的扩展主要是侵占农田,其次是灌丛和草地。③楠溪江流域陆域生态健康得分75.82,处于良好水平。其中,评分优秀的评价单元1个,占流域面积的21.67%,为岩坦镇,评分良好的评价单元15个,占流域面积的76.83%,评分一般的评价单元2个,为东瓯街道和江北街道,占流域面积的1.50%。④在陆域生态健康状况评估的9项指标中,楠溪江流域的森林覆盖率、景观破碎度、重要生境保持率、水源涵养保持功能、土壤保持功能、建设面积比例和受保护区面积比例等7项指标均处于良好及以上水平,陆域生态环境保护较好,点源、面源污染负荷指标处于一般水平。⑤楠溪江流域水域生态健康得分为60.51分,处于良好水平。在水域生态健康状况评估的7项指标中,水资源开发利用强度、枯水期径流量占同期年均径流量比例两项指标评价为优秀,水质达标率、鱼类物种多样性两项指标评价为良好,水生生境干扰指数、特有性物种保持率两项指标评价为一般,河道流通性指标评价为差。⑥ 楠溪江流域生态健康综合评估得分为69.70分,处于良好水平。其中,评价为良好的评估单元个数为16个,占流域面积的98.50%,评价为一般的评估单元两个,为东瓯街道和江北街道,限制因子主要为森林覆盖率和不透水面积比例。⑦流域存在的主要问题包括:城镇用地面积快速增长,农田、草地、灌丛等生态系统持续退化,生态系统稳定性降低;总体水质状况不容乐观;河道连通性较差等。
[Abstract]:Watershed is an important source of life for human beings and other animals and plants. In the process of sustainable social and economic development in China, The quality of the watershed ecosystem has become a constraint that can not be ignored. Through the evaluation of the ecosystem health of the Nanxi River Basin, The purpose of this paper is to provide scientific decision-making basis for the coordinated and sustainable development of economy and environment in Nanxi River Basin. Firstly, combining RS and GIS technology, the present situation and type change of ecosystem composition in Nanxi River Basin are analyzed. The evaluation index system of land area and water area is constructed with reference to the technical guide of watershed ecosystem health assessment of the Ministry of Environmental Protection. Among them, the land area includes three types of indicators, namely, land ecological pattern, land ecological function and land ecological pressure, among which there are nine indexes, including land ecological pattern, land ecological function and land ecological pressure. The water body, including the habitat structure of water, aquatic organisms and ecological pressure of the waters, were used to evaluate the ecosystem health of 18 evaluation units in Nanxi River Basin. The main problems in the basin were analyzed. The conclusions of the study include: 12014, Forest is the main ecosystem in Nanxi River basin, the proportion is 82.99, followed by farmland, town and wetland type, the proportion is 7.964.90% and 3.430.22000-2014, respectively. The farmland forest and farmland town transfer areas in Nanxi River Basin are 59.35kmm2 and 42.14kmm2, respectively, which together account for 56.29km of the total ecosystem conversion area. The ecosystem type conversion mainly occurs between farmland, forest and town during 14 years. The expansion of cities and towns in Nanxi River Basin is mainly to encroach on farmland, followed by thickets and grassland. 3 Nanxi River basin land ecological health score is 75.82, which is at a good level, among which, there is one evaluation unit with excellent score, accounting for 21.67 percent of the basin area, which is Yantan Town. There were 15 evaluation units with good score, which accounted for 76.83 of the basin area, and two general evaluation units, including Dongou street and Jiangbei street, which accounted for 1.50.4 of the basin area in 9 indicators of land ecological health assessment. The forest coverage, landscape fragmentation, important habitat conservation rate, water conservation function, soil conservation function, construction area ratio and protected area ratio of Nanxi River Basin are all in good or above level. The pollution load index of point source and non-point source is at general level. 5. The ecological health score of Nanxi river basin is 60.51, and it is in good level. The intensity of water resources exploitation and utilization, the proportion of runoff to average annual runoff in the dry season were excellent, the water quality was up to the standard, the fish species diversity was good, and the disturbance index of aquatic habitat was good. The evaluation of two indexes of endemic species conservation rate was general, and that of river channel fluidity index was 69.70 points for comprehensive assessment of ecological health in Nanxi River basin, which was at a good level, among which the number of evaluation units was 16. It accounts for 98.50 of the basin area. It is evaluated as two general assessment units, two streets in Dongou and the streets in the north of the Yangtze River. The limiting factors are mainly forest coverage and impermeable area. The main problems in the basin include the rapid growth of urban land area. Farmland, grassland, thickets and other ecosystems continue to degenerate, ecosystem stability is reduced, the overall water quality is not optimistic, river connectivity is poor, and so on.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X826

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