福建长汀红壤区植被覆盖度变化趋势分析

Dynamics of vegetation coverage in the red soil area of Changting,Fujian,China

福建长汀位于中国南方亚热带红壤丘陵区,水土流失、山体滑坡等自然灾害较为严重,分析当地植被覆盖度的变化趋势是评价水土流失治理及生态环境恢复的有效手段。以Landsat数据为基础,应用地理信息系统(GIS)技术,提取福建省长汀红壤区2000-2014年的归一化植被指数(NDVI)值,并采用像元二分模型和差值法分别对植被覆盖度、植被恢复等级进行估算。结果表明,15 a长汀红壤区NDVI呈明显上升趋势,植被覆盖度呈明显增加趋势,高植被覆盖面积增加了2 132.90 km2,面积比例提高68.86%,植被变化以恢复和完全恢复为主,占全区总面积的88.07%。经过多年的治理,长汀红壤区植被覆盖状况已得到很大改善,但仍有占长汀土地总面积0.42%的区域属植被严重退化区,主要分布于汀江两岸,建议在该流域加强水土流失治理保护措施,合理生产开发利用,从而有效防治水土流失。

Changting County of Fujian is in the subtropical red soil hilly area, south of China, suffering from water and soil loss and landslides. Study on the dynamics of local vegetation coverage is the effective measure to evaluate the control of soil and water loss and the restoration of ecological environment. The normalized difference vegetation indexes （ NDVI ） from 2000 to 2014 were collected from Landsat data to calculate the vegetation coverage and restoration in the red soil area of Changting, Fujian Province by the geographic information system （GIS） and the dimidiate pixel model and difference operation. The results indicated as follows. During the 15 years in the red soil area of Changting, the normalized difference vegetation indexes （NDVI） and the vegetation coverage had a significant increase. The area of high vegetation coverage increased by 68.86% and 2 132.90 km^2. Vegetation changes in order to restore and fully restore the main, accounting for 88.07% of the total area of the region. Although, the overall vegetation in Changting had a significant recovery, there are still some area that occupied 0.42% turned to severe degradation, which are mainly located on the two sides of Ting River. Therefore, it is suggested to strengthen soil and water conservation and rational utilization and production in the valley.