School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA.
Proc Natl Acad Sci U S A. 2010 Mar 30;107(13):5786-91. doi: 10.1073/pnas.0905455107. Epub 2010 Mar 25.
Among the myriad complications involved in the current food crisis, the relationship between agriculture and the rest of nature is one of the most important yet remains only incompletely analyzed. Particularly in tropical areas, agriculture is frequently seen as the antithesis of the natural world, where the problem is framed as one of minimizing land devoted to agriculture so as to devote more to conservation of biodiversity and other ecosystem services. In particular, the "forest transition model" projects an overly optimistic vision of a future where increased agricultural intensification (to produce more per hectare) and/or increased rural-to-urban migration (to reduce the rural population that cuts forest for agriculture) suggests a near future of much tropical aforestation and higher agricultural production. Reviewing recent developments in ecological theory (showing the importance of migration between fragments and local extinction rates) coupled with empirical evidence, we argue that there is little to suggest that the forest transition model is useful for tropical areas, at least under current sociopolitical structures. A model that incorporates the agricultural matrix as an integral component of conservation programs is proposed. Furthermore, we suggest that this model will be most successful within a framework of small-scale agroecological production.
在当前粮食危机所涉及的众多复杂问题中,农业与自然界其他部分的关系是最重要的问题之一,但仍未得到充分分析。特别是在热带地区,农业经常被视为与自然世界相对立的,问题的框架是将用于农业的土地最小化,以便将更多土地用于保护生物多样性和其他生态系统服务。特别是,“森林转变模型”预测了一个过于乐观的未来,即农业集约化程度的提高(每公顷产量的提高)和/或农村向城市的移民增加(减少用于农业的森林砍伐的农村人口),这表明在不久的将来,热带地区将有更多的造林和更高的农业产量。我们回顾了生态理论的最新发展(表明片段之间的迁移和本地灭绝率的重要性),并结合经验证据,认为森林转变模型对于热带地区几乎没有什么用处,至少在当前的社会政治结构下是这样。我们提出了一个将农业基质纳入保护计划的整体组成部分的模型。此外,我们认为,在小规模生态农业生产的框架内,该模型将最成功。