西昌地区实施退耕还林工程后的景观格局变化

Landscape Changes after Conversion of Cropland to Forest Project Implementation in Xichang Area

利用西昌市1996和2004年2期TM影像数据,对西昌地区实施退耕还林工程以来的景观格局变化进行分析。结果表明1996—2004年,西昌地区林地面积增长明显,草地面积迅速减少,耕地面积略有增长,耕地、林地和草地类型间的转化频繁;耕地景观随着斑块数和斑块密度的减少破碎度降低,而林地和草地的破碎度增加;耕地和林地斑块形状不规则性增强;就整体景观而言,西昌地区林地的优势度进一步提高,景观均匀度下降。建议在今后实施退耕还林工程时,合理安排还林和还草任务,同时对退耕后耕地面积仍有增长的现象给予关注。

The landscape pattern dynamics after conversion of cropland to forest project in Xichang area was analyzed by using the TM multispectrum remote sensing of 1996 and 2004. The results indicated that the area of the main landscape types had an area change. The area of forestland had increased obviously,the area of grassland had decreased rapidly,and the area of cropland had increased slightly,the transformation between the main landscape types was obvious. The landscape dynamics could be summarized as follows: the fragmentation degree of cropland landscape had decreased with the NP and PD reducing,while the fragmentation degree of forestland and cropland had increased. The patch shape of forestland and grassland had become more irregular than ever. The dominance degree of forestland had increased,while the evenness degree of the whole landscape had declined slightly. The whole landscape had made an unbalanced development. It suggested that the rational assignment of forest and grass would be arranged in the conversion of cropland to forest project in the future,and area after conversion would be paid much attention to the increase of cropland.