Geography Department, Humboldt-Universität zu Berlin, 10099 Berlin, Germany;
Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). doi: 10.1073/pnas.2100436118.
Agricultural expansion into subtropical and tropical forests causes major environmental damage, but its wider social impacts often remain hidden. Forest-dependent smallholders are particularly strongly impacted, as they crucially rely on forest resources, are typically poor, and often lack institutional support. Our goal was to assess forest-smallholder dynamics in relation to expanding commodity agriculture. Using high-resolution satellite images across the entire South American Gran Chaco, a global deforestation hotspot, we digitize individual forest-smallholder homesteads ( = 23,954) and track their dynamics between 1985 and 2015. Using a Bayesian model, we estimate 28,125 homesteads in 1985 and show that forest smallholders occupy much larger forest areas (>45% of all Chaco forests) than commonly appreciated and increasingly come into conflict with expanding commodity agriculture (18% of homesteads disappeared; = 5,053). Importantly, we demonstrate an increasing ecological marginalization of forest smallholders, including a substantial forest resource base loss in all Chaco countries and an increasing confinement to drier regions (Argentina and Bolivia) and less accessible regions (Bolivia). Our transferable and scalable methodology puts forest smallholders on the map and can help to uncover the land-use conflicts at play in many deforestation frontiers across the globe. Such knowledge is essential to inform policies aimed at sustainable land use and supply chains.
农业向亚热带和热带森林扩张会造成重大环境破坏,但它更广泛的社会影响往往被隐藏起来。依赖森林的小农受到的影响尤为严重,因为他们严重依赖森林资源,往往比较贫困,而且通常缺乏体制支持。我们的目标是评估与商品农业扩张相关的森林-小农动态。我们使用整个南美洲大查科地区的高分辨率卫星图像(一个全球森林砍伐热点地区),对 23954 个个体森林-小农住地进行数字化,并追踪它们在 1985 年至 2015 年期间的动态。使用贝叶斯模型,我们估计 1985 年有 28125 个住地,并表明森林小农占据的森林面积比通常所认识到的要大得多(占大查科所有森林的 45%以上),并且越来越多地与商品农业的扩张相冲突(有 18%的住地消失; = 5053)。重要的是,我们证明了森林小农日益被生态边缘化,包括所有查科国家的森林资源基础大量损失,以及越来越多的小农被限制在更干燥的地区(阿根廷和玻利维亚)和较难到达的地区(玻利维亚)。我们可推广的可扩展方法将森林小农纳入地图,并有助于揭示全球许多森林砍伐前沿地区的土地利用冲突。这种知识对于为可持续土地利用和供应链提供信息的政策至关重要。