宁夏沙坡头国家级自然保护区植被覆盖变化及其稳定性

发布时间：2018-06-17 13:45

本文选题：沙坡头国家级自然保护区 + FVC　；参考：《兰州大学》2015年硕士论文

【摘要】：干旱沙漠保护区是沙漠生态系统和绿洲生态系统的连接地带,是两个系统间物质循环、能量转换及信息传递的重要场所。植被资源的退化与消失、土壤盐渍化、动物资源的减少等问题日益显现,给人类的生存环境造成威胁。研究干旱沙漠保护区的植被健康状态及其演变,评估对生态系统稳定性的影响,探究人与自然和谐共存的可持续发展模式,对于保护区的可持续管理具有指导意义。本文以位于腾格里沙漠东南缘的沙坡头国家级自然保护区为研究对象,基于遥感影像资料实际情况,与植被生长季节变化相结合,选取保护区1990-2011年多期遥感数据(1990年、2001年、2007年、2011年),经过分析与比较后,分别从植被、景观和群落三个层次评价。首先提取保护区内植被覆盖度和覆盖类型的动态变化宏观规律信息,然后对植被整体覆盖和覆被类型的动态变化以及稳定性作简要分析,最后,再对保护区关键植被群落辨识后对其稳定性进行详细评价。通过研究,主要得到以下结论：(1)由于保护区独特的自然地理位置的特殊性,在人为作用的改造下,植被分布格局呈现“东高西低,南高北低”的特点。低等级覆盖度区域面积减少,高等级植被覆盖度区域面积增加。植被覆盖呈现先减后增的波动趋势,总体上植被恢复面积大于退化面积,具有“局部改善,少量恶化,大部分保持不变”的特点。植被恢复以中度改善为主,明显改善次之；植被恢复以轻微退化为主,中度退化次之。(2)保护区植被覆盖类型可以分为人工林、灌丛、草甸和栽培作物四类,覆盖面积由高到低为人工林灌丛栽培作物草甸。植被类型的变化划分为两个阶段：1990-2001年,除了栽培作物的面积增加外,其余覆盖类型均减少；2001-2011年,人工林、灌丛、栽培作物的面积呈增加趋势,草甸面积波动减少。具有“天然植被灌丛稳定,草甸亚稳定；人工栽培植被防护林稳定,栽培作物亚稳定,用材林不稳定”的特征。(3)保护区内群落结构简单,物种多样性低、分布极其不均匀,占有绝对优势的为矮小的灌木群落,稳定性较高。由于荒漠生态系统的物种多样性并不十分复杂,使得灌木群落的生态学地位极其显著,发挥着不可替代的作用,群落的稳定性和生态功能也主要由灌木层中的优势种决定,物种的丧失或群落组成的改变都会对干旱荒漠生态系统造成巨大的影响。
[Abstract]:The arid desert reserve is the link zone between desert ecosystem and oasis ecosystem. It is an important place for material circulation, energy conversion and information transmission between the two systems. The degradation and disappearance of vegetation resources, the salinization of soil and the decrease of animal resources are becoming more and more serious, which threaten the living environment of human beings. It is of guiding significance for the sustainable management of protected areas to study the health status and evolution of vegetation, assess the impact on ecosystem stability, and explore the sustainable development model of harmonious coexistence between man and nature. This paper takes Shapotou National Nature Reserve located in the southeastern margin of Tenggeli Desert as the research object. Based on the actual situation of remote sensing image data, it combines with the seasonal variation of vegetation growth. Multi-period remote sensing data from 1990 to 2011 (1990, 2001, 2007, 2011) were selected. After analysis and comparison, vegetation, landscape and community were evaluated respectively. Firstly, the macroscopical information of dynamic change of vegetation coverage and cover type is extracted, and then the dynamic change and stability of vegetation cover and cover type are analyzed briefly. The stability of the key vegetation communities was evaluated in detail after the identification of the key vegetation communities. The main conclusions are as follows: (1) owing to the particularity of the special natural geographical location of the reserve, the vegetation distribution pattern presents the characteristics of "the east high and the west low, the south high and the north low" under the artificial transformation. The area of low grade coverage decreased and high grade vegetation increased. The vegetation cover showed a fluctuating trend of first decreasing and then increasing. On the whole, the area of vegetation restoration was larger than that of degraded area, which had the characteristic of "local improvement, small deterioration, most of which remained unchanged". The vegetation cover types of protected areas can be divided into four types: artificial forest, shrub, meadow and cultivated crops. The coverage area from high to low is the meadow of cultivated crops in artificial forest and shrub. The change of vegetation type was divided into two stages: 1990-2001. Except for the increase of cultivated crop area, all the other cover types decreased from 2001 to 2011. The area of artificial forest, shrub and cultivated crops showed an increasing trend, and the fluctuation of meadow area decreased. It has the characteristics of "natural vegetation shrub stability, meadow substability, artificial cultivation vegetation shelter forest stability, cultivated crops substability, timber forest instability".) the community structure in the reserve is simple, species diversity is low, and distribution is extremely uneven. The dominant shrub community is the dwarf shrub community with high stability. Because the species diversity of desert ecosystem is not very complex, the ecological status of shrub community is extremely significant and plays an irreplaceable role. The stability and ecological function of the community are mainly determined by the dominant species in shrub layer. Loss of species or changes in community composition will have a significant impact on arid desert ecosystems.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q948

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