利用枚举法分析典型草原区退化群落的空间变化

Analysis of the Spatial Change of Degraded Communities in Typical Steppe Using Statistical Enumeration Method

以内蒙古典型草原为研究区,通过遥感和地理信息系统等技术的支持,采用MATLAB编写一个枚举法程序,统计在不同时段内整个研究区所有斑块的变化轨迹,同时对变化归类重新赋新属性再反馈到空间上,研究不同变化轨迹的空间分布规律。通过该方法的应用初步得出以下结论:(1)从20世纪70年代末到本世纪初,研究区植被发生了根本性的变化,保持30年不变的群落斑块只占总面积的1/3,其余均发生了不同程度的变化。(2)不同区域、不同年代的植被变化不同,20世纪70年代末到20世纪80年代末主要集中在羊草和大针茅群落的轻度、中度退化类型上,并向较重的退化方向发展。20世纪80年代末到本世纪初植被的退化主要向重度退化类型变化。(3)近30年来,在受到强降雨和强蒸发的交互作用的影响下,分布在研究区低湿地周围的地带性植被向盐碱化趋势发展。

Through RS, GIS and other technical support, used MATLAB a statistical enumeration program was wrriten to analyse the change trail of vegetation spot in different time throughout Inner Mongolia typical steppe, and give the changed classification new attributes and then feedback to the space and research the spatial change law of different changed trail. The results showed that： （1）From the late 1970s to the beginning of this century, there had been great changes in vegetation. The unchanged communities area was only 1/3 of the total area in 30 years. The rest changed in different degrees. （2） Vegetation change occured differently in different areas and various years,and concentrated on mild, moderate degraded communities（ Leymus chinensis Tzvel. and Stipa grandis P. Smirn） from the late 1970s to the late 1980s mainly, and developed toward heavily degraded vegetation. From the late 1980s to the beginning of this century, vegetation changed toward more heavily degradated types. （3）In recent 30 years, under the mutual effect of strong rainfall and strong evaporation, typical steppe vegetation around the low wetland in the studied area is developing toward the trend of salinization.