呼伦贝尔生态功能区草地退化的时空特征

Grassland degradation monitoring and spatio-temporal variation analysis of the Hulun Buir Ecological Function Region

草地退化已经成为当前重要的生态环境和社会经济问题,遥感和地理信息系统技术的发展为草地退化问题的研究提供了新的手段和方法。本文利用长时间序列的MODIS数据,采用基于植被覆盖度的草地退化监测方法,对2003-2012年10年期间呼伦贝尔生态功能区草地进行了动态监测,并结合土地利用类型变化和气候数据对草地退化指数的年际变化进行了驱动力分析。结果表明:2003-2012年,呼伦贝尔草地生态环境表现较为脆弱,草地退化指数年际间变化剧烈;生态功能区草地退化等级全区呈差异分布,西部地区较中东部地区退化现象严重,但是近几年西部地区草地退化现象有所好转,东部地区有所加重;结合气象和人为因素综合分析表明,极端气候和采矿、工业建设等人类活动是功能区草地生态系统质量变化的主要驱动力。

Grassland degeneration has resulted in a series of social, economic and ecosystem environmental problems, so monitoring changes in grassland is very important. With the development of technology, Remote Sensing （RS） and GIS provide new means for the study of grassland degeneration. Based on the classification of grassland degradation degree calculated by vegetation coverage, we introduced the Grassland Degradation Index （GDI）to characterize grassland degradation in our focal area. The value range of GDI is from 0 to 5. When GDI is large, it means that the area of grassland degradation is more serious. When GDI〉4, it means there is extremely severe degradation and when GDI 〈1, it shows that there is no degradation of pasture in the area. Hulun Buir Grassland was dynamically monitored from 2003 to 2012 using long time series of MODIS data and the two indicators of vegetation coverage and GDI. Finally, the driving force of changes during the ten years were analyzed combined with meteorological data. The results indicate that the Hulun Buir Grassland Ecosystem is fragile, and interannual variability of GDI is dramatic. There is spatial heterogeneity in the grassland degradation degree： grassland degrades more seriously in the west than in the central and eastern regions. In recent years, however, grassland degradation in the central and eastern region has aggravated while the west region has improved. Moreover, the comprehensive analysis of meteorological and artificial factors shows that changes in Hulun Buir Grassland Ecosystem quality are mainly affected by extreme climate, mining and industrial construction.