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Monitoring the spatio-temporal dynamics of swidden agriculture and fallow vegetation recovery using Landsat imagery in northern Laos 被引量:5
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作者 LIAO Chenhua FENG Zhiming +1 位作者 LI Peng ZHANG Jinghua 《Journal of Geographical Sciences》 SCIE CSCD 2015年第10期1218-1234,共17页
Swidden agriculture is an age-old, widespread but controversial farming practice in Montane Mainland Southeast Asia (MMSEA). In the uplands of northern Laos, swidden ag- riculture has remained a predominant human-do... Swidden agriculture is an age-old, widespread but controversial farming practice in Montane Mainland Southeast Asia (MMSEA). In the uplands of northern Laos, swidden ag- riculture has remained a predominant human-dominated land-use type for centuries. However swidden system has undergone dramatic transformations since the mid-1990s. Debates on changes in swidden cultivation are linked to globally critical issues, such as land use/cover changes (LUCC), biodiversity loss and environmental degradation. Since the implementation of Reducing Emissions from Deforestation and Forest Degradation (REDD), much attention has been paid nationally and internationally to swidden agriculture in the tropics. However, knowledge of the explicitly spatial characteristics of swidden agriculture and the conse- quences of these transitions at macroscopic scale is surprisingly scarce. In this study, the intensity of swidden use and fallow forest recovery in northern Laos in 1990, 2002, and 2011 were delineated by means of Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM+) imagery (30 m) using a decision tree classification approach, followed by an analysis of the spatio-temporal changes in swidden agriculture. Next, annual successive TM/ETM+ images during 2000-2010 were used to delineate the dynamics of the burning and cropping phase. Subsequently, the burned pixels identified in 2000 were compared respectively with their counterparts in the following years (2001-2011) to investigate temporal trends, land-use frequency, and the swidden cycle using time-series Landsat-based Normalized Difference Vegetation Index (NDVI) data. Finally, as the swidden cycle changed from 1 to 11 years, the fallow vegetation recovery process was studied. The results showed that: (1) from 1990 to 2011, the area of swidden agriculture increased by 54.98%, from 1.54× 10^5 ha to 2.38×10^5 ha in northern Laos. The increased swidden cultivation area was mainly distributed in Luang Prabang and southern Bokeo, whereas the decreased parts were mainly found in Phongsali; (2) swidden agriculture increased mainly at elevations of 500-800 m, 300-500 m, and 800-1000 m and on slopes of 10°-20° and 200-30°. Over 80% of swidden fields were transformed from forests; (3) during 2000-2011, the frequency of swidden use in northern Laos was about two or three times. The interval between two successive utilization of a swidden ranged from one to seven years. Comparison of swidden cycles and the related proportions of swidden farming in 2000, 2003, and 2007 revealed that swidden cycles in most areas were shortened; and (4) there was a significant correlation (0.97) between fallow vegetation recovery and the swidden cycle. The NDVI of regenerated vegetation could approach the average level of forest when the swidden cycle reached 10 years. 展开更多
关键词 swidden agriculture spatio-temporal changes swidden cycle frequency of swidden use fallow vegetation recovery LANDSAT Laos
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Detecting and mapping annual newly-burned plots(NBP) of swiddening using historical Landsat data in Montane Mainland Southeast Asia(MMSEA) during 1988–2016 被引量:6
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作者 李鹏 封志明 +2 位作者 肖池伟 BOUDMYXAY Khampheng 刘宇 《Journal of Geographical Sciences》 SCIE CSCD 2018年第9期1307-1328,共22页
Swidden agriculture is by far the dominant land use system in the uplands of Southeast Asia (SEA), as well as other tropical regions, which plays an important role in the implementation of Reducing Emissions from De... Swidden agriculture is by far the dominant land use system in the uplands of Southeast Asia (SEA), as well as other tropical regions, which plays an important role in the implementation of Reducing Emissions from Deforestation and Forest Degradation (REDD) of United Nations. To our knowledge, the long-term inter-annual area of newly burned plots (NBP) of swidden agriculture in mainland Southeast Asia is still not available, let alone in the whole tropics. With the strengthening regional geo-economic cooperation in SEA, swidden agriculture has experienced and/or is still experiencing extensive and drastic transformations into other diverse market-oriented land use types since the 1990s. In this study, high-level surface reflectance products of Landsat 4151718 family sensors including Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI) acquired in March, April and May of each year between 1988 and 2016 were firstly utilized to detect and monitor the extent and area of NBP of swidden agriculture with multiple thresholds of four commonly-used vegetation indices, namely the Normalized Difference Vegetation Index (NDVI), Normalized Difference Moisture Index (NDMI), Normalized Burn Ratio (NBR) and Soil Adjusted Vegetation Index (SAVI), in combination with local phenological features of swid- dening and topographical data. The results showed that: (1) an annual average of 6.08×104 km2 of NBP of swidden agriculture, or 3.15% of the total land area of MSEA, were estimated in the past nearly three decades. (2) Annual NBP were primarily distributed in four major geomorphic units including the Central Range of Hills, Northern Mountainous Region, West- ern Myanmar Hills, and Annamite Chain. (3) A decadal average analysis indicated that the NBP of swidden agriculture opened year by year declined as a whole, especially after 2010, merely with an average of 5.23×104 km2. (4) The top ten provincial administrative units in Cambodia, Laos, Myanmar, Thailand and Vietnam, which consistently accounted for over 90% of the newly opened swiddens of each country, showed distinct fluctuations in usingslash-and-burn practices in the last decades. The Landsat-based (30 m) reconstructed 29-year longitudinal updated maps (including extent and area) of the NBP of swidden agri- culture may contribute to REDD and local livelihood related studies in Continental Southeast Asia. Our study further demonstrated that the multiple vegetative indices thresholds approach holds great potential in detecting swidden agriculture in tropical mountainous regions. 展开更多
关键词 swidden agriculture phenology newly-burned plots (NBP) LANDSAT Montane Mainland SoutheastAsia (MMSEA)
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西双版纳热带山地利用过程中的土壤退化 被引量:12
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作者 张萍 刘宏茂 +2 位作者 陈爱国 刘志秋 付永能 《山地学报》 CSCD 2001年第1期9-13,共5页
土壤养分和土壤微生物生长代谢水平的衰退是热带山地退化的重要表现形式 ,二者的变化基本是一致的 ,即从热带雨林→ 33a次生林→ 6a轮歇地→ 4a轮歇地→旱谷地→橡胶林→荒草坡呈降低趋势 ;相对于热带雨林而言 ,不同利用方式土壤微生物... 土壤养分和土壤微生物生长代谢水平的衰退是热带山地退化的重要表现形式 ,二者的变化基本是一致的 ,即从热带雨林→ 33a次生林→ 6a轮歇地→ 4a轮歇地→旱谷地→橡胶林→荒草坡呈降低趋势 ;相对于热带雨林而言 ,不同利用方式土壤微生物和土壤养分状况均有不同程度的下降 ,且随退化程度增高减幅增大 ,土壤微生物衰减的速率比土壤养分的衰减更快。说明山地的退化严重影响着土壤微生物的生长代谢水平以及它们之间的协同作用 ,从而影响土壤碳氮循环代谢途径 ,降低土壤肥力水平。 展开更多
关键词 轮歇系统 种植系统 退化 土壤微生物 土壤养分
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喜玛拉雅地区山地旱冬瓜轮歇与间作系统研究 被引量:11
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作者 沈立新 《中国生态农业学报》 CAS CSCD 2003年第1期148-149,共2页
种植在农地上的旱冬瓜能促进农作物生长,据测定1t旱冬瓜树叶干物质量的肥力相当于14.3kg硫酸铵、2.4kg过磷酸钙和2.2kg硫酸钾,农户习惯以鲜叶6000~7500kg/hm^2替代1.5万kg/hm^2水稻种植的有机圈肥,并分析了喜玛拉雅地区印度东北部和中... 种植在农地上的旱冬瓜能促进农作物生长,据测定1t旱冬瓜树叶干物质量的肥力相当于14.3kg硫酸铵、2.4kg过磷酸钙和2.2kg硫酸钾,农户习惯以鲜叶6000~7500kg/hm^2替代1.5万kg/hm^2水稻种植的有机圈肥,并分析了喜玛拉雅地区印度东北部和中国云南省以旱冬瓜为基础的混农林轮作丢荒管理系统。 展开更多
关键词 喜玛拉雅地区 间作系统 轮作模式 旱冬瓜 经营管理
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Livelihood Factors and Household Strategies for an Unexpected Climate Event in Upland Northern Laos 被引量:1
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作者 Phanxay INGXAY Satoshi YOKOYAMA Isao HIROTA 《Journal of Mountain Science》 SCIE CSCD 2015年第2期483-500,共18页
Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this... Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this area is one such climate event, and it has occurred earlier and with less regularity in recent years. Not all households are able to cope with these changes. This study examines the ability of local farmers to cope with rice insufficiency. This investigation also clarifies household strategies in dealing with the climate event. We randomly interviewed 63 of 95 household heads, and performed a paired sample t test to examine the significance of differences in three household groups between the 2010 normal climate and the 2011 climate event. The groups were categorized according to rice selfsufficiency in 2011: groups I are households with rice self-sufficiency, group II are those facing a rice shortage of up to 3 months, and group III are those with insufficient rice for over 3 months. We also conducted a one-way ANOVA to examine the significance of differences in livelihood strategies among the three groups. We found that the household labor force was the most important factor in enhancing the villagers' ability to deal with the climate event and that the level of impact of that event shaped their coping strategies. Households with substantial labor force had more options for coping strategies than those with smaller ones. The villagers faced different levels of impact and adopted differentcoping strategies accordingly. Non-timber forest product collection was the principle livelihood strategy in response to non-climate factors such as education, access to health services, provision of equipment and clothing, and overcoming the impact of the climate event. Households heavily affected by the early rainy season onset tended to engage in intensive activities such as off-farm activity and outside work, rather than their major livelihood activities in the village(upland crop and livestock production). 展开更多
关键词 Climate events Livelihood factors Livelihood change Household strategy swidden
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Forested Farmlands:Forest Management by Agroforestry Symbiosis in A Land Management Framework in South and South East Asia
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作者 Syed Ajijur Rahman Yulia Rahma Fitriana Kilian Walz 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期109-109,共1页
Forests provide multiple benefits as a safety net to the poor and also help to increase the overall ecological balance.Of particular importance in this respect this research has been conducted in six typical villages ... Forests provide multiple benefits as a safety net to the poor and also help to increase the overall ecological balance.Of particular importance in this respect this research has been conducted in six typical villages in South and Southeast Asia,located in Northern Bangladesh,Southern Myanmar and Northwest Thailand.Data collection methods were used by means of observation,FGD,interviews,and a structured survey of farm households.Data were analyzed through qualitative methods 展开更多
关键词 swidden AGROFORESTRY FARMERS FOREST management
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Biocultural Diversity of Sarangani Province, Philippines: An Ethno-Ecological Analysis
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作者 Florence Lasalita ZAPICO Catherine Hazel AGUILAR +2 位作者 Angelie ABISTANO Josephine Carino TURNER Lolymar Jacinto REYES 《Rice science》 SCIE CSCD 2015年第3期138-146,共9页
This paper discussed effects of lowland-associated influences on upland ecology, food security and biocultural diversity in the Sarangani farming communities of the Philippines. In the uplands of Sarangani Province, t... This paper discussed effects of lowland-associated influences on upland ecology, food security and biocultural diversity in the Sarangani farming communities of the Philippines. In the uplands of Sarangani Province, the conservation of traditional rice varieties, the centrality of rice in tribal life, and the continued observance of planting rituals attest to its cultural significance and convey a common desire for cultural preservation and community solidarity. Economic and socio-political pressures had transformed tribal communities, although vestiges of traditional farming systems are still being practiced in remote sitios(villages). Changing land use patterns had also resulted in shrinking farm sizes and consequently in food insecurity in the Sarangani uplands. Extractive industries(i.e. logging, mining and charcoal making) and swidden farming were observed to cause widespread environmental degradation, while modern agriculture had undermined the capacity of indigenous peoples to survive because of their complete dependence on lands and resources. With the reality that cultural and biological diversities are inextricably linked, trans-disciplinary strategies coupling indigenous knowledge systems with scientific knowledge should, therefore, be instituted to save the Sarangani upland ecosystem, the indigenous peoples and their tribal resources. 展开更多
关键词 indigenous knowledge system rice swidden farming traditional agriculture
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