Geographical accessibility and land-use and land-cover dynamics: The case of Nang Rong district, Northeast Thailand.

摘要

Two main issues were hypothesized to affect the composition and spatial structure of land use patterns in Northeast Thailand: land use/land cover (LULC) policies at the national, regional, and local levels, and geographic accessibility of villagers to communities and associated land territories. The policy analysis employed a documentary-style approach to describe the changes in environmental policy and LULC over time in the Northeast. The LULC change and road connectivity analysis used a time-series of aerial photography for 1954, 1967, 1984, and 1994. The photos were scan-digitized into a seamless image database and interpreted for the four time periods. Road connectivity was calculated using Alpha and Gamma indices. LULC change in spatially-buffered areas were assessed for the all-weather roads for Nang Rong district for 1954 and 1984, and pattern metrics were calculated to examine the composition and spatial organization of LULC over time and space.; Problems of soil quality, land degradation, land management, land allocation, and land rights were addressed within the policy analysis. Obstacles to their full assessment and management included the lack of consistent implementation of LULC policies due to changing governments and alternate land initiatives. The connectivity indices showed an increase through time, thereby, indicating that the road network was more connected across the image time-series. Further, the indices indicated that greater access to land resulted in greater compositional and organizational shifts in LULC types. Spatial buffers and ecological pattern metrics indicated that the areas closer to roads were deforested earlier and to a greater degree. Also, a greater number of forest patches were found closer to the all-weather roads, and they were smaller in size, thereby, suggesting greater land fragmentation. Results of T-tests indicated that the closer to the road, the greater was the change to non-forest. Geomorphic setting and LULC change were explicitly linked, thereby, suggesting that the density of forest to non-forest increased within 200 meters from the road in all landform types.