基于空间信息技术的贵南县草地退化研究

以景观生态学理论为基础,利用1976、1996、2001、2006年四期遥感影像,采用遥感(RS)和地理信息系统(GlS)相结合的方法.探讨了贵南县草地景观的变化特征.结果表明:1)30年来,贵南县草地面积减少了59 046.13 hm2,占责南县草地面积的12.62%.平均每年减少0.42%,草地退化严重.草地的退化不仅表现在数量上,草地质量也明显下降,高覆盖度草地面积明显减少,净减少量达106 076.80 hm2,减少率达28.87%;2)贵南县草地景观破碎化显著,1976、1996、2001、2006年草地景观的分维值分别为1.519 3、1.501 1、1.496 7和1.675 4.表明贵南县草地受人为因素影响较大;3)从动态度看,1976-1996年高覆盖度草地对草地整体变化影响较大,该时期草地退化严重;1996-2006年,草地面积基本处于平稳状态.

Study on grassland degradation in Guinan County based on spatial information techniques

On the basis of landscape ecology theory,remote sensing images of four periods(1976,1996,2001,and 2006) were used to analyze the changeable characteristics of grasslands in Guinan County by combining RS technique and GIS technique.This study indicated that the 59 046.13 ha grassland lost in the past 30 years,taking up 12.62% of the total grassland area in Guinan County.Accompanying by loss of grassland,the quality of grassland reduced greatly.The high cover grassland area was greatly decreased by 106076.80ha,accounting for 28.87% of the total high coverage grassland area.The fragmentation of grassland was greatly obvious in the past three decades in Guinan.The fractal dimension values of grassland in 1976,1996,2001 and 2006 were 1.519 3,1.501 1,1.496 7,1.675 4,respectively,indicating that grassland landscape had been greatly disturbed by human activities.Changes of the high cover grassland from 1976 to 1996 had a strong effect on grassland degradation and the grassland area nearly kept stable during 1996-2006.