Dressler Wolfram H, Wilson David, Clendenning Jessica, Cramb Rob, Keenan Rodney, Mahanty Sango, Bruun Thilde Bech, Mertz Ole, Lasco Rodel D
School of Geography, University of Melbourne, 221 Bouverie, Parkville, VIC, 3070, Australia.
World Agroforestry Centre (ICRAF), International Rice Research Institute, UPLB, College, Philippines Office, 2nd Floor, Khush Hall Building, PO Box 35024, 4031, Los Baños, Laguna, Philippines.
Ambio. 2017 Apr;46(3):291-310. doi: 10.1007/s13280-016-0836-z. Epub 2016 Nov 16.
Global economic change and policy interventions are driving transitions from long-fallow swidden (LFS) systems to alternative land uses in Southeast Asia's uplands. This study presents a systematic review of how these transitions impact upon livelihoods and ecosystem services in the region. Over 17 000 studies published between 1950 and 2015 were narrowed, based on relevance and quality, to 93 studies for further analysis. Our analysis of land-use transitions from swidden to intensified cropping systems showed several outcomes: more households had increased overall income, but these benefits came at significant cost such as reductions of customary practice, socio-economic wellbeing, livelihood options, and staple yields. Examining the effects of transitions on soil properties revealed negative impacts on soil organic carbon, cation-exchange capacity, and aboveground carbon. Taken together, the proximate and underlying drivers of the transitions from LFS to alternative land uses, especially intensified perennial and annual cash cropping, led to significant declines in pre-existing livelihood security and the ecosystem services supporting this security. Our results suggest that policies imposing land-use transitions on upland farmers so as to improve livelihoods and environments have been misguided; in the context of varied land uses, swidden agriculture can support livelihoods and ecosystem services that will help buffer the impacts of climate change in Southeast Asia.
全球经济变化和政策干预正推动东南亚高地地区从长期休耕的轮垦（LFS）系统向其他土地利用方式转变。本研究对这些转变如何影响该地区的生计和生态系统服务进行了系统综述。在1950年至2015年间发表的17000多项研究中，根据相关性和质量筛选后，确定了93项研究进行进一步分析。我们对从轮垦向集约化种植系统的土地利用转变的分析显示了几个结果：更多家庭的总体收入有所增加，但这些收益是以巨大代价换来的，比如传统习俗减少、社会经济福祉降低、生计选择受限以及主要作物产量下降。研究转变对土壤性质的影响发现，这对土壤有机碳、阳离子交换能力和地上碳都有负面影响。总体而言，从长期休耕的轮垦向其他土地利用方式，尤其是向集约化多年生和一年生经济作物种植转变的直接和潜在驱动因素，导致先前的生计安全以及支持这种安全的生态系统服务大幅下降。我们的研究结果表明，那些为改善生计和环境而强制高地农民进行土地利用转变的政策受到了误导；在土地利用方式多样的背景下，轮垦农业能够支持有助于缓冲东南亚气候变化影响的生计和生态系统服务。
