干旱半干旱区山地生态系统脆弱性评估方法体系与实例研究

发布时间：2018-05-25 21:48

本文选题：干旱半干旱区 + 山地生态系统　；参考：《华东师范大学》2017年硕士论文

【摘要】：干旱半干旱区山地生态系统是我国北方地区重要的生物栖息地与生物多样性中心,具有水源涵养、防风固沙、土壤保持、科学研究等多种生态服务功能。但是,由于山地生态系统内生的易损性和不稳定性,在全球变化与人类活动的影响下,表现出明显的生态脆弱性特征。因此,如何提高干旱半干旱区山地生态系统的稳定性是保护干旱半干旱区生态资源环境的关键所在。这就需要研究相应的技术方法体系为区域生态系统的有效管理提供指导意见。本研究旨在构建基于VSD模型的干旱半干旱区山地生态系统脆弱性评估框架体系并以宁夏贺兰山为例进行实证分析。研究内容主要包括:区域主要暴露源的辨别,生态系统受到干扰后的敏感性和自适应力,暴露、敏感性、适应性之间的相互关系,以及区域生态脆弱性时空分布。研究结果如下:(1)时间角度来看,1988年至2013年,宁夏贺兰山生态脆弱性等级由重度脆弱转变为中度脆弱,生态环境脆弱性分级指数从7.4下降到5.3,研究区各等级生态脆弱性相互转化的总面积为1770km2,综合动态度为77%,并且整体呈现出由高脆弱性向低脆弱性方向转移的趋势。其中,重度脆弱区变化量最大,占研究区总面积的38.3%,主要转化为中度脆弱区,减少面积占总面积的42.4%。区域内基本无分级区转化为极度脆弱区。(2)从空间格局上来看,宁夏贺兰山生态脆弱性整体呈现中部高四周低的分布格局。1988年生态脆弱性等级与坡度等级间呈现出两端低中间高的发生规律,重度和极度脆弱区集中发生在坡度25°～40°范围内。2013年与1988年类似。说明随着时间变化,生态脆弱性等级的空间分布在坡度上无明显变化。与高程叠置结果也显示出相似的发生规律,即海拔低和海拔高的地方脆弱性等级面积少,最大值基本于1500～2000m范围内出现。(3)干旱半干旱区山地生态系统脆弱性评价方法体系具有一定指导意义。研究区域生态环境状况不断改善,生态脆弱度明显降低,这与宁夏贺兰山国家级自然保护区建立后贺兰山生态环境状况的变化相吻合,说明本研究构建的框架模型具有实际指导意义,对于干旱半干旱区山地生态系统的暴露-敏感-适应关系做出了定量描述,从而为干旱半干旱区山地系统管理提供了有效技术支撑。
[Abstract]:The mountainous ecosystem in arid and semi-arid areas is an important biological habitat and biodiversity center in northern China. It has many ecological service functions, such as water conservation, wind and sand control, soil conservation, scientific research and so on. However, due to the vulnerability and instability of mountain ecosystems, the global changes and human activities have shown obvious characteristics of ecological vulnerability. Therefore, how to improve the stability of mountainous ecosystem in arid and semi-arid areas is the key to protect the ecological resources and environment in arid and semi-arid areas. Therefore, it is necessary to study the corresponding technical method system to provide guidance for the effective management of regional ecosystem. The purpose of this study is to construct a framework system for assessing the vulnerability of mountainous ecosystems in arid and semi-arid areas based on VSD model and take Helan Mountain in Ningxia as an example to make an empirical analysis. The main contents of the study include: the identification of the main sources of exposure, the sensitivity and adaptability of ecosystem after disturbance, the relationship between exposure, sensitivity and adaptability, and the temporal and spatial distribution of regional ecological vulnerability. The results are as follows: (1) from 1988 to 2013, the grade of ecological vulnerability of Helan Mountain in Ningxia changed from severe vulnerability to moderate vulnerability. The index of ecological environment vulnerability decreased from 7.4 to 5.3. The total area of ecological vulnerability transformation was 1770km2, and the comprehensive dynamic degree was 777.The whole showed the trend from high vulnerability to low vulnerability. Among them, the severe vulnerable area has the largest change, accounting for 38.3% of the total area of the study area, which is mainly transformed into the moderate vulnerable area, and the reduced area accounts for 42.4% of the total area. In terms of spatial pattern, the basic non-grading area in the region is transformed into extremely vulnerable area. The ecological fragility of Helan Mountain in Ningxia presented a distribution pattern of high, high and low in the middle of the region. In 1988, the ecological vulnerability grade and slope grade showed the occurrence law of low middle height at both ends. Severe and extremely vulnerable areas are concentrated in the gradient range of 25 掳to 40 掳. 2013 is similar to 1988. It shows that the spatial distribution of ecological vulnerability level has no obvious change in slope with time change. The results of superposition with elevation also show a similar pattern, that is, the area of vulnerability grade is low in low altitude and high in altitude. The maximum value appeared in the range of 1500 ~ 2000m. (3) the evaluation method system of mountain ecosystem vulnerability in arid and semi-arid areas has certain guiding significance. The status of ecological environment in the study area has been continuously improved, and the degree of ecological fragility has been obviously reduced, which coincides with the changes of ecological environment of Helan Mountain after the establishment of the National Nature Reserve of Helan Mountain in Ningxia. The results show that the frame model constructed in this study is of practical significance, and the relationship between exposure, sensitivity and adaptation of mountainous ecosystem in arid and semi-arid areas is described quantitatively. It provides an effective technical support for the management of mountainous system in arid and semi-arid areas.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X826

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