Land use change in Thimphu, Bhutan from 1990--2007: Effects of cultural, political, and economic frameworks.

摘要

Secluded in the foothills of the Himalayas between China and India, Bhutan is still subject to many of the same problems facing other developing nations. Environmental degradation is one of these challenging problems, especially due to modernization pressures from urban population growth and economic pressures to generate jobs to accommodate the incoming population. Rural-urban migration analysis is completed by a Geographic Information Systems (GIS) analysis of various 2005 Bhutan census variables from the Population and Housing Census of Bhutan (PHCB). The areas of highest in and out-migration are located, then variables identified as potential push and pull factors for migration (such as health and education) are analyzed. The specific area of interest for this study is Thimphu, the capital of Bhutan.The primary goal of this research is to identify discrepancies in the national forest inventory and recommend appropriate methodology for using Remote Sensing (RS) and GIS to quantify the amount of forest cover. Political ecology studies show that structural adjustment programs such as land privatization, decentralization, and blueprint based environmental planning exert major impacts on agriculture and land use. In Bhutan, land privatization and decentralization of various administrative boundaries have already caused significant changes to policy regarding forestland in the past two decades. These political and economic impacts affect forest policies in terms of accessibility, control, and management. The land use land cover change was determined using unsupervised classifications, coupled with a post-classification change detection technique, to obtain quantitative change information from Landsat images taken at three different points in time (1990, 1999, and 2007). These techniques were applied at various scales including the city scale and two administrative boundary scales (Dzongkhag and Gewog).Remote Sensing analysis shows that at the city and geog levels, urban area is increasing, while forested area is decreasing. At the dzongkhag level, however, there was an increase in forested areas. The GIS migration analysis shows that Thimphu dzongkhag has received the highest in-migration, while Trashigang dzongkhag has the highest out-migration. Analysis of the various push variables shows that access to certain amenities, such as health care, electricity, and roads, are major reasons to immigrate to Thimphu dzongkhag. The national government has enacted several policies and programs in an effort to reduce rural-urban migration and to maintain a sustainable forest cover, such as the rural-electrification project and promotion of Non-wooded Forest Products (NWFP), but these policies and programs did not make a significant impact on either of the intended targets. The research finds that GIS and RS are useful tools for analyzing the impact of political, social, and economic modernization pressures on the physical environment.