Montane Mainland Southeast Asia Research Articles

A Review on Livelihood Diversification: Dynamics, Measurements and Case Studies in Montane Mainland Southeast Asia

A Review on Livelihood Diversification: Dynamics, Measurements and Case Studies in Montane Mainland Southeast Asia

Detecting and mapping annual newly-burned plots (NBP) of swiddening using historical Landsat data in Montane Mainland Southeast Asia (MMSEA) during 1988–2016

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 4/5/7/8 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 swiddening 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, Western 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 using slash-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 agriculture 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.

Extent and Area of Swidden in Montane Mainland Southeast Asia: Estimation by Multi-Step Thresholds with Landsat-8 OLI Data

Information on the distribution, area and extent of swidden agriculture landscape is necessary for implementing the program of Reducing Emissions from Deforestation and Forest Degradation (REDD), biodiversity conservation and local livelihood improvement. To our knowledge, explicit spatial maps and accurate area data on swidden agriculture remain surprisingly lacking. However, this traditional farming practice has been transforming into other profit-driven land use, like tree plantations and permanent cash agriculture. Swidden agriculture is characterized by a rotational and dynamic nature of agroforestry, with land cover changing from natural forests, newly-cleared swiddens to different-aged fallows. The Operational Land Imager (OLI) onboard the Landsat-8 satellite has visible, near-infrared and shortwave infrared bands, which are sensitive to the changes in vegetation cover, land surface moisture content and soil exposure, and therefore, four vegetation indices (VIs) were calculated, including the Normalized Difference Vegetation Index (NDVI), the Normalized Difference Moisture Index (NDMI), the Normalized Burn Ratio (NBR) and the Soil Adjusted Vegetation Index (SAVI). In this study, we developed a multi-step threshold approach that uses a combination of thresholds of four VIs and local elevation range (LER) and applied it to detect and map newly-opened swiddens and different-aged fallows using OLI imagery acquired between 2013 and 2015. The resultant Landsat-derived swidden agriculture maps have high accuracy with an overall accuracy of 86.9% and a Kappa coefficient of 0.864. The results of this study indicated that the Landsat-based multi-step threshold algorithms could potentially be applied to monitor the long-term change pattern of swidden agriculture in montane mainland Southeast Asia since the late 1980s and also in other tropical regions, like insular Southeast Asia, South Asia, Latin America and Central Africa, where swidden agriculture is still common.

Monitoring the spatio-temporal dynamics of swidden agriculture and fallow vegetation recovery using Landsat imagery in northern Laos

Swidden agriculture is an age-old, widespread but controversial farming practice in Montane Mainland Southeast Asia (MMSEA). In the uplands of northern Laos, swidden agriculture 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 consequences 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 1.54×105 ha to 2.38×105 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 20°–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.

Greater diurnal temperature difference, an overlooked but important climatic driver of rubber yield

The increase of rubber demand has led to rapid expansion of rubber plantations from optimal environments in the humid tropics of Southeast Asia into suboptimal environments in montane mainland Southeast Asia. Nevertheless, rubber yields can be surprisingly high in sub-optimal environments. This paper investigates climatic factors which contribute to the higher than expected rubber yields in a suboptimal environment in Jinghong, Yunnan, Southwest China. Two mathematical analysis methods were used to relate climate to rubber yield and dry matter content: partial least square regression and classification and regression tree models were used. Greater diurnal temperature difference was found to increase dry rubber yield, and has been previously overlooked as an explanatory factor. Average temperatures below 25.7°C, and more sunshine hours in the day before tapping, were also found to significantly improve dry rubber yield, although more sunshine hours during the month prior to tapping were found to reduce rubber yield. Lower relative humidity was found to increase dry rubber content of latex and increase yield. Greater diurnal temperature difference and more sunshine hours in a day before tapping facilitate photosynthesis and rubber formation. Lower relative humidity reduces the water content in the latex, thus increasing dry rubber content of the latex.In summary, this study finds that lower average temperature (within certain thresholds), greater diurnal temperature difference in both a day and a month before tapping, more sunshine hours in a day before tapping and lower sunshine hours in a month before tapping are the most important factors which promote dry rubber yield, and lower relative humidity in the day prior to tapping is the most important factor in determining dry rubber content of latex. Diurnal temperature difference has not been previously investigated as a driver of rubber yield. The case study site has a greater diurnal temperature difference than many other main rubber producing areas, which may contribute to explaining why rubber yields in Jinghong are higher than might be expected in a sub-optimal environment.

Through the Technology Lens: The Expansion of Rubber and its Implications in Montane Mainland Southeast Asia

Natural latex from the rubber tree (Hevea brasiliensis) is a hot commodity, with consumption increasing worldwide at an average rate of 5.8% per year since 1900. The vast majority of the world's rubber supply has historically come from the wet-humid tropics of Southeast Asia, but researchers in China have successfully developed new hybrids that grow well in areas with cooler temperatures and a distinct dry season. Today, investors are promoting rubber plantations in non-traditional rubber growing areas of Laos, Cambodia, Myanmar, northeast Thailand, and northwest Vietnam. By critically assessing the impacts of this expansion of rubber and clarifying the relationship between tools and technologies, the paper suggests that the widespread adoption of rubber as a technology leads to loss of natural and agricultural biodiversity; greater use of surface and groundwater supplies; increased use of pesticides, fertilisers, and other chemicals; higher exposure to market booms and busts for smallholders and investors; and for some farmers, the loss of their land to industrial plantations on which they may become labourers. The paper argues that if state authorities recognise the double-edged nature of rubber as a technology, they can act to try to limit its damaging effects through polices that recognise secure tenure and encourage small-scale, diversified agroforestry systems.

Soil Carbon Stocks Decrease following Conversion of Secondary Forests to Rubber (Hevea brasiliensis) Plantations

Forest-to-rubber plantation conversion is an important land-use change in the tropical region, for which the impacts on soil carbon stocks have hardly been studied. In montane mainland southeast Asia, monoculture rubber plantations cover 1.5 million ha and the conversion from secondary forests to rubber plantations is predicted to cause a fourfold expansion by 2050. Our study, conducted in southern Yunnan province, China, aimed to quantify the changes in soil carbon stocks following the conversion from secondary forests to rubber plantations. We sampled 11 rubber plantations ranging in age from 5 to 46 years and seven secondary forest plots using a space-for-time substitution approach. We found that forest-to-rubber plantation conversion resulted in losses of soil carbon stocks by an average of 37.4±4.7 (SE) Mg C ha−1 in the entire 1.2-m depth over a time period of 46 years, which was equal to 19.3±2.7% of the initial soil carbon stocks in the secondary forests. This decline in soil carbon stocks was much larger than differences between published aboveground carbon stocks of rubber plantations and secondary forests, which range from a loss of 18 Mg C ha−1 to an increase of 8 Mg C ha−1. In the topsoil, carbon stocks declined exponentially with years since deforestation and reached a steady state at around 20 years. Although the IPCC tier 1 method assumes that soil carbon changes from forest-to-rubber plantation conversions are zero, our findings show that they need to be included to avoid errors in estimating overall ecosystem carbon fluxes.

Swidden, rubber and carbon: Can REDD+ work for people and the environment in Montane Mainland Southeast Asia?

Swidden (also called shifting cultivation) has long been the dominant farming system in Montane Mainland Southeast Asia (MMSEA). Today the ecological bounty of this region is threatened by the expansion of settled agriculture, including the proliferation of rubber plantations. In the current conception of REDD+, landscapes involving swidden qualify almost automatically for replacement by other land-use systems because swiddens are perceived to be degraded and inefficient with regard to carbon sequestration. However, swiddening in some cases may be carbon-neutral or even carbon positive, compared with some other types of land-use systems. In this paper we describe how agricultural policies and institutions have affected land use in the region over the last several decades and the impact these policies have had on the livelihoods of swiddeners and other smallholders. We also explore whether incentivizing transitions away from swiddening to the cultivation of rubber will directly or reliably produce carbon gains. We argue that because government policies affect how land is used, they also influence carbon emissions, farmer livelihoods, environmental services, and a host of other variables. A deeper and more systematic analysis of the multiple consequences of these policies is consequently necessary for the design of successful REDD+ policies in MMSEA, and other areas of the developing world. REDD+ policies should be structured not so much to ‘hold the forest boundary’ but to influence the types of land-use changes that are occurring so that they support both sustainable livelihoods and environmental services, including (but not limited to) carbon.

Hydro-climatic effects of future land-cover/land-use change in montane mainland southeast Asia

Regional climate model simulations with RegCM3 were performed to investigate how future land-cover/land-use (LCLU) change in Montane Mainland Southeast Asia (MMSEA) could affect regional climate. Simulation land-surface parameterizations included present day and plausible 2050 land-covers, as well as two extreme deforestation simula- tions. In the simulations, the original land cover map of RegCM3, based on AVHRR 1992- 93 observations, was replaced with one obtained from MODIS 2001 observations; and the model was set to work at two different spatial resolutions using the sub-grid feature of the land surface model: 27.79 km for the atmosphere and 9.26 km for the land surface. During validation, modeled precipitation closely matched observed precipitation over southern China, but underestimated precipitation in the Indochina Peninsula. The plausible 2050 LCLU simulation predicted little change in regional climate. However, an extreme irrigated crop parameterization caused precipitation to increase slightly in the Indochina Peninsula, decrease substantially in southeastern China, and increase significantly in the South China Sea. The extreme short-grass parameterization caused substantial precipitation decreases in MMSEA, but few changes elsewhere. These simulations indicate in order for significant

Mapping fallow lands in Vietnam's north-central mountains using yearly Landsat imagery and a land-cover succession model

The objective of this article is to investigate whether it is possible to use Landsat data together with ancillary data and temporal context to accurately identify land covers found in the fallow areas of Montane Mainland Southeast Asia's (MMSEA's) difficult-to-map swidden landscapes. A rule-based non-parametric hybrid classification method that integrates knowledge about the vegetation regrowth patterns in these landscapes with analysis of Landsat imagery is developed. The method is applied to three upland districts of the Nghe An Province, Vietnam. The results show that the hybrid classification approach, with an overall accuracy of 90%, is superior to using a traditional maximum likelihood classifier, which generated an overall accuracy of 68%. The hybrid classification results indicate that the landscape is dominated by bush and bamboo, while the maximum likelihood classification suggests a landscape that is predominantly grass covered. The hybrid classification results are in agreement with local knowledge and information from fieldwork-based reports and articles on swidden systems in the study area and other parts of MMSEA.

Simulating Land-Cover Change in Montane Mainland Southeast Asia

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 50years 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.

Hydrologic effects of the expansion of rubber (Hevea brasiliensis) in a tropical catchment

AbstractThis study investigates basin‐scale hydrologic implications of the replacement of forest‐dominated land cover by rubber plantations in Montane Mainland Southeast Asia. The paper presents a new method for estimating the water demand of rubber and consequently water losses to the atmosphere through rubber evapotranspiration (ET). In this paper we argue that rubber ET is energy‐limited during the wet season, but during the dry season water consumption is mostly governed by environmental variables that directly affect rubber phenology, namely, vapour pressure deficit, temperature and photoperiodicity. The proposed ET model is introduced into a hillslope‐based hydrologic model to predict the basin‐scale hydrologic consequences of rubber replacing native vegetation. Simulations suggest greater annual catchment water losses through ET from rubber dominated landscapes compared to traditional vegetation cover. This additional water use reduces discharge from the basin, or its storage. Copyright © 2010 John Wiley & Sons, Ltd.

Environmental Consequences of the Demise in Swidden Cultivation in Montane Mainland Southeast Asia: Hydrology and Geomorphology

The hydrological and geomorphological impacts of traditional swidden cultivation in Montane Mainland Southeast Asia are virtually inconsequential, whereas the impacts associated with intensified replacement agricultural systems are often much more substantial. Negative perceptions toward swiddening in general by governments in the region beginning half a decade ago have largely been based on cases of forest conversion and land degradation associated with (a) intensified swidden systems, characterized by shortened fallow and extended cropping periods and/or (b) the widespread cultivation of opium for cash after the Second World War. Neither of these practices should be viewed as traditional, subsistence-based swiddening. Other types of intensive agriculture systems are now replacing swiddening throughout the region, including semi-permanent and permanent cash cropping, monoculture plantations, and greenhouse complexes. The negative impacts associated with these systems include changes in streamflow response, increased surface erosion, a higher probability of landslides, and the declination in stream water quality. Unlike the case for traditional swiddening, these impacts result because of several factors: (1) large portions of upland catchments are cultivated simultaneously; (2) accelerated hydraulic and tillage erosion occurs on plots that are cultivated repetitively with limited or no fallowing to allow recovery of key soil properties, including infiltration; (3) concentrated overland flow and erosion sources are often directly connected with the stream network; (4) root strength is reduced on permanently converted hillslopes; (5) surface and ground water extraction is frequently used for irrigation; and (6) and pesticides and herbicides are used. Furthermore, the commercial success of these systems relies on the existence of dense networks of roads, which are linear landscape features renowned for disrupting hydrological and geomorphological systems. A new conservation focus is needed to reduce the impacts of these intensified upland agricultural practices.

Changing farming systems in Montane Mainland Southeast Asia, resiliency and climate change

This article was submitted without an abstract, please refer to the full-text PDF file.

Changing farming systems in Montane Mainland Southeast Asia, resiliency and climate change

Changing farming systems in Montane Mainland Southeast Asia, resiliency and climate change

A multi-level perspective on conserving with communities: Experiences from upper tributary watersheds in montane mainland Southeast Asia

A multi-level perspective on conserving with communities: Experiences from upper tributary watersheds in montane mainland Southeast Asia

A multi-level perspective on conserving with communities: Experiences from upper tributary watersheds in montane mainland Southeast Asia

Mountains provide habitat for human and non-human life as well as many ecosystem goods and services useful to society at multiple spatial levels. In this paper we show that adopting a multi-level perspective allows for a more nuanced understanding of the governance challenges arising in the management of upper tributary watersheds for conservation purposes. Rather than assuming that the correct and best levels are known we look at how discourses privilege certain levels over others and how decisions about levels are made. Social groups, resources, places and institutions have scale-like characteristics which can confound simplistic models for conserving with communities. Communities are heterogeneous, vaguely bounded and shift levels. People belong to multiple communities. Resources are used-up and services valued at different spatial levels from those at which they may be ruled and managed. Areas of jurisdictions, resource characteristics and capacities of authority at particular levels may not coincide very well. Integration and segregation of use and conservation is, in part, an issue of resolution and frequency with which a landscape is viewed. The multi-level perspective on conserving with communities described in this paper helps better understand why the expectations of different actors are hard to satisfy and projects are perceived as failures. Some of the differences are a result of looking at the system from different levels and others the failure to acknowledge important cross-level interactions. It suggests that there is no a priori reason to privilege one level to the exclusion of consideration of all others in setting conservation objectives, nor in finding ways to meet them. The burdens and benefits of conservation should not be borne by, or accrue to, just one level.

Agricultural Commercialisation, Diversification, and Conservation of Renewable Resources in Northern Thailand Highlands

The process of commercialisation-diversification in the highlands of upper northern Thailand and the accompanying dismissal of self-subsistence are documented based on the findings from seven case studies carried out in different agricultural and social situations during the past decade. The characteristics of the key driving forces powering this agrarian transition such as rapid economic growth, decrease in the share of labour employed in the agriculture, urbanization and changes in food consumption patterns, and improved communication infrastructures, are presented in the Thai context. The environmental impact of these profound agrarian transformations on the degradation of key renewable resources, particularly soil erosion, is assessed. Their socio-economic consequences on an extensive differentiation among farming households and equity issues are also discussed. Finally the authors draw several lessons from this Thai experience that illustrate the very strong adaptive capacity of small highland farmers. They could be useful in similar agro-ecological zones of neighbouring countries that are presently experiencing the same kind of agricultural transition in the Montane Mainland Southeast Asia ecoregion. Particularly, the article underlines the need for more holistic and integrated approaches to agricultural development and the management of renewable resources in highland agro-ecosystems to alleviate poverty while conserving the resource base.

Land Use Transition, Livelihoods, and Environmental Services in Montane Mainland Southeast Asia

The present article provides an overview of the status of land use and land cover change science in Montane Mainland Southeast Asia in the context of a Mobile Workshop. Outcomes of the Mobile Workshop highlighted the rapid changes in land use and livelihoods, largely driven by the development of transport links, increasing market access, and trade liberalization. While many of these changes are likely to be beneficial, they must be carefully monitored, and relevant policies should be inclusive of all stakeholders. This is why it is important that land use science be cognizant of the need to make information accessible to policy-makers and land users.

Multi-level Scenarios for Exploring Alternative Futures for Upper Tributary Watersheds in Mainland Southeast Asia

Abstract Nested scenarios at 2 spatial levels were constructed to explore key uncertainties about how livelihoods and landscapes in upper tributary watersheds of montane mainland Southeast Asia might unfold in the coming decades. At the regional level the scenarios highlight the implications of different forms of market and political integration. At the upper tributary level the scenarios highlight changing dependencies on local natural resources and the extent of empowerment of local stakeholders in their management. The scenarios are intended as a starting point for discussions among stakeholders, as a framework for designing and interpreting land use and land cover change simulation studies, and as a tool to help identify resilient livelihood and regional development strategies. The multi-level approach to scenario building introduced here shows considerable promise for mountain regions, as it encourages analyses to be cognizant of broader-scale economic and social changes as well as the uncertainties ...