纵向岭谷区公路沿线土地利用变化与扩展效应

运用A RC I/NFO软件,对纵向岭谷区内典型公路沿线1km、2km、5km和20km缓冲带土地利用数据进行分析。通过土地利用转移矩阵、土地利用程度综合指数和扩展强度指数,研究了公路沿线土地变化及公路的扩展效应。研究表明:①各缓冲带内均存在林地向耕地和草地退化的现象;②研究区自然状况完好,林地与草地所占比例之和均超过土地总面积的80%,但存在一定的内部差异性;③景洪各缓冲带土地利用程度排序为La2k0m>La5km>La2km>La全区>La1km,保山土地开发利用程度高于景洪,排序情况La1km>La2km>La5km>La全区≈La2k0m;④公路的扩展效应与土地利用程度综合指数基本上是一致的,但扩展效应不显著。受地形地貌条件的限制,公路扩展效应的影响阈为公路周边1～5km。

Landuse Changes and Expansion Effects Caused by Road Construction in Longitudinal Range-Gorge Region

Longitudinal Range-Gorge Region is peculiar for its high mountains and deep gorges,abundant bio-diversities,frangile eco-environment and so on.Road is the primary traffic means in this area and the expansion effects caused due to road construction are distinguishable from those of plain area.Based on the digital land-use maps of 1985 and 2000 and road maps obtained from Resources Data Center of CAS,selecting typical section of highways,the land-use changes of the Longitudinal Range-Gorge Region were analyzed using the software of ArcGIS 8.1 and through traditional statistical analyzing methods.The cases of the study are located in Jinghong and Baoshan cities including the urban areas and the road buffer zones with width of 1km,2km,5km and 20km along the roads.In the paper,land-use transfer matrix representing the changes of land-use structure,the index of land-use degree representing the land-use intensity and the index of expansion intensity were used as the reflection of the expansion effects of the road construction.The main conclusions are given as follows:①The transformation of land-use pattern in the study area showed that some forests have been converted to grassland and cultivated land,indicating that ecosystem has degraded.②Changes of land-use structure showed that forest and grassland dominated and the ecosystem was well preserved in the Longitudinal Range-Gorge Region,however,there were some artificial interference in the region.Land-use degree was determined by the local economic level and the land-use policies and the like.③The sequence according to the index of land-use extend is La20km>La5km>La2km>Laregion>La1km in Jinghong,and La1km>La2km>La5km>Laregion≈La20km in Baoshan.④There were expansion effects of the road construction in the Longitudinal Range-Gorge Region but the effects were inapparent both in expansion and in intensity comparing with those of the plain area.The expansion effects of road construction were restricted by local natural conditions and economic developing level.The scope was 1km to 5km along the road.