青藏高原生态屏障生态系统时空演变及驱动机制

青藏高原生态屏障是我国生态安全战略格局的重要组成部分，对我国乃至亚洲生态安全具有重要的屏障作用。研究青藏高原生态屏障生态格局的演变规律，探究影响生态系统变化的驱动机制，对青藏高原生态屏障建设和保障国家生态安全具有重要的意义。利用多源遥感数据，分析了2000-2015年国家屏障区生态格局演变规律，选取了自然和社会经济等驱动要素，采用冗余分析等方法解析了青藏高原生态屏障生态系统演变机制。结果表明：（1）2000-2015年间，青藏高原生态屏障生态系统格局发生明显变化，草地生态系统减少了1792 km²，主要转化为荒漠生态系统和河流生态系统，转换面积分别为1088 km²和832 km²；河流生态系统增加了1600 km²，主要由荒漠生态系统和草地生态系统转换而来，分别转换了1152 km²和832 km²。（2）2000-2015年青藏高原生态屏障生态系统格局演变驱动机制中以社会经济因子为主。冗余分析结果显示国内生产总值（83%）和人口数量（72%）贡献率最大；方差分析结果中国内生产总值和人口数量的共同贡献率达到了77%；地理加权回归结果显示生态系统演变受社会经济因子主导的区域面积比例为60.41%。（3）青藏高原生态屏障内人口数量的总贡献率达到了72%，在人口数量作用下生态系统呈正向转换的面积占比达到了86.24%，且人口数量与河流、森林生态系统的相关程度较高，综合说明了青藏高原生态屏障内生态保护政策的实施、生态工程的建设卓有成效。

Spatiotemporal ecosystem evolution and driving mechanism in the Qinghai-Tibet Plateau ecological barrier area

The Qinghai-Tibet Plateau ecological barrier area is an important part of China''s ecological security strategic pattern and plays an important role in protecting the ecological security of China and even Asia. It is of great significance to study the spatiotemporal dynamics of the ecosystem and explore the driving forces that affect change in the ecosystem in the Qinghai-Tibet Plateau ecological barrier area. Based on multi-source remote sensing data, this paper analyzed the change in the ecosystem in the Qinghai-Tibet Plateau ecological barrier area from 2000 to 2015. We selected the natural and social economic factors as the driving factors, and the change mechanism of the ecological system in the Qinghai-Tibet Plateau ecological barrier area was analyzed by redundancy analysis and other methods. The results showed the following:(1) The ecological pattern of the Qinghai-Tibet Plateau ecological barrier area changed significantly between 2000 and 2015. The grassland ecosystem was reduced by 1792 km², which was mainly transformed into desert ecosystem and river ecosystem, with 1088 km² and 832 km² converted, respectively. The river ecosystem increased by 1600 km², which was mainly converted from desert ecosystem and grassland ecosystem, with 1152 km² and 832 km² converted respectively. (2) From 2000 to 2015, the socio-economic factors were the main driving mechanism for the evolution of ecosystem pattern on the Qinghai-Tibet Plateau ecological barrier area. The redundancy analysis results showed that Gross domestic product(GDP) (83%) and Population(POP) (72%) contributed the most. In the results of analysis of variance, the joint contribution rate of GDP and POP reached 77%. The results of geographical weighted regression showed that the proportion of the area dominated by socio-economic factors was 60.41%. (3) The contribution rate of POP in the Qinghai-Tibet Plateau ecological barrier area reached 72%, the area of the positive transformed ecosystem reached 86.24% under the effect of POP. Moreover, POP was highly correlated with the river and forest ecosystems. All of these showed that the implementation of the ecological protection policy and the construction of ecological projects in the Qinghai-Tibet Plateau ecological barrier area have been effective.