四川马边彝族自治县土地利用/覆被变化分析

采用基于最大似然法的监督分类方法对四川省马边彝族自治县1988年和2001年两期Landsate5 TM影像进行解译，利用单项土地利用动态指数〖WTBX〗（LUDI）、双向土地利用动态指数（Ki）以及土地利用类型转移矩阵（Cx×y）〖WTBZ〗等定量分析方法分析解译结果，得到马边县13年间土地利用/覆被动态及转移特征，并对可能的生态影响进行了分析预测。结果显示：①次生林面积增加，针叶林面积有所下降，灌草地被农田大量取代；②城镇及居民点和次生林的动态最为活跃，转入面积明显高于转出面积；③中山区和亚高山区林地构成发生变化，高山草甸面积有所萎缩，河谷区的阔叶林带被次生林大量取代，低山河谷区的土地破碎化程度增加。研究表明，13年间马边土地利用/覆被变化具有动态高、转换活跃、空间性强以及人为活动干扰影响明显等特点。其中，低山丘陵区的灌草坡大量被农地替代、中山区和亚高山区次生林面积扩大应该作为生态退化的信号加以重视。另外，气候变化对马边森林植被演替可能产生的影响应在今后进行深入的分析研究

LAND USE/COVER CHANGE IN MABIAN YI AUTONOMOUS COUNTY,SICHUAN PROVINCE

Based on Landsat 5 TM imagines and GIS，the land use/cover change (LUCC) of Mabian Yi autonomous county from 1988 to 2001 were analyzed quantitatively with land use dynamic index (LUDI)，land use dynamic model (〖WTBX〗Ki〖WTBZ〗) and land use transfer matrix (〖WTBX〗Cx×y〖WTBZ〗).Moreover，the ecological impacts of LUCC were analyzed and discussed.The area and percentage of secondary forest increased.Oppositely，the area of coniferous forests decreased.In low hill regions，bush slope land was replaced by agricultural lands.The dynamics of town and inhabitant，secondary forest were more dynamic；the areas transferring into these two types were more than that transferred out from them.The land cover pattern changed clearly.The vegetation composing in middle high mountains regions changed and the area of mountain meadow shrank.In low hills and valley regions，land cover pattern of agricultural land and bush land became more fragmental.The results illuminated that the LUCC and the land cover pattern of Mabian have dynamic characters，being transferried actively，with strong spatial and intensive impact of human beings.Moreover，the increase in area of secondary forest and the replacing of bush land by agricultural land should be concerned as signals of ecological degradation.Meanwhile，it is also indicated that the possible impact of climate changes on forest succession should be monitored in future.〖