Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Mais filtros

Base de dados
Intervalo de ano de publicação
Environ Manage ; 49(5): 968-79, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22476665


We used the conversion of land use and its effects (CLUE-s) model to simulate scenarios of land-cover change in Montane mainland southeast Asia (MMSEA), a region in the midst of transformation due to rapid intensification of agriculture and expansion of regional trade markets. Simulated changes affected approximately 10 % of the MMSEA landscape between 2001 and 2025 and 16 % between 2001 and 2050. Roughly 9 % of the current vegetation, which consists of native species of trees, shrubs, and grasses, is projected to be replaced by tree plantations, tea, and other evergreen shrubs during the 50 years period. Importantly, 4 % of this transition is expected to be due to the expansion of rubber (Hevea brasiliensis), a tree plantation crop that may have important implications for local-to-regional scale hydrology because of its potentially high water consumption in the dry season.

Agricultura/métodos , Agricultura/tendências , Altitude , Conservação dos Recursos Naturais/métodos , Modelos Teóricos , Ásia Sudeste , Simulação por Computador , Produtos Agrícolas/crescimento & desenvolvimento , Monitoramento Ambiental , Árvores/crescimento & desenvolvimento , Clima Tropical
Environ Manage ; 36(3): 394-403, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16132447


This paper summarizes land-cover and land-use change at eight sites in Thailand, Yunnan (China), Vietnam, Cambodia, and Laos over the last 50 years. Project methodology included incorporating information collected from a combination of semiformal, key informant, and formal household interviews with the development of spatial databases based on aerial photographs, satellite images, topographic maps, and GPS data. Results suggest that land use (e.g. swidden cultivation) and land cover (e.g. secondary vegetation) have remained stable and the minor amount of land-use change that has occurred has been a change from swidden to monocultural cash crops. Results suggest that two forces will increasingly determine land-use systems in this region. First, national land tenure policies-the nationalization of forest lands and efforts to increase control over upland resources by central governments-will provide a push factor making it increasingly difficult for farmers to maintain their traditional swidden land-use practices. Second, market pressures-the commercialization of subsistence resources and the substitution of commercial crops for subsistence crops-will provide a pull factor encouraging farmers to engage in new and different forms of commercial agriculture. These results appear to be robust as they come from eight studies conducted over the last decade. But important questions remain in terms of what research protocols are needed, if any, when linking social science data with remotely sensed data for understanding human-environment interactions.

Conservação dos Recursos Naturais/história , Meio Ambiente , Árvores , Agricultura , Altitude , Ásia Sudeste , Conservação dos Recursos Naturais/economia , Monitoramento Ambiental , História do Século XVIII , Humanos , Condições Sociais
Environ Manage ; 36(3): 404-13, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15995894


This study investigated land-use and land-cover change in three hamlets and two state rubber farms in the Nan-e watershed of the Xishuangbanna prefecture of Yunnan province in Southwestern China. The overall objective of the study was to understand how state policies affected land use and land cover and how changes in these variables affected farmer vulnerability to economic, social, and political events. Emphasis was placed on the cultivation of rubber (Hevea brasiliensis), promoted in southern Yunnan province since the 1950s as a means to meet the demands of rapid economic development. The study combined remote sensing analysis with secondary data and in-field interviews in order to understand the coupling between land-use and land-cover change and farmer vulnerability in light of the geographic, historical, and sociopolitical situation.

Conservação dos Recursos Naturais , Meio Ambiente , Agricultura/economia , China , Comércio , Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/legislação & jurisprudência , Humanos , Formulação de Políticas , Política , Fatores de Risco , Borracha , Condições Sociais