Steffan-Dewenter Ingolf, Kessler Michael, Barkmann Jan, Bos Merijn M, Buchori Damayanti, Erasmi Stefan, Faust Heiko, Gerold Gerhard, Glenk Klaus, Gradstein S Robbert, Guhardja Edi, Harteveld Marieke, Hertel Dietrich, Höhn Patrick, Kappas Martin, Köhler Stefan, Leuschner Christoph, Maertens Miet, Marggraf Rainer, Migge-Kleian Sonja, Mogea Johanis, Pitopang Ramadhaniel, Schaefer Matthias, Schwarze Stefan, Sporn Simone G, Steingrebe Andrea, Tjitrosoedirdjo Sri S, Tjitrosoemito Soekisman, Twele André, Weber Robert, Woltmann Lars, Zeller Manfred, Tscharntke Teja
Department of Agroecology, Georg-August-Universität Göttingen, Waldweg 26, 37073 Göttingen, Germany.
Proc Natl Acad Sci U S A. 2007 Mar 20;104(12):4973-8. doi: 10.1073/pnas.0608409104. Epub 2007 Mar 14.
Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by approximately 75% and species richness of forest-using species by approximately 60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by approximately 40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.
热带雨林破坏和农业集约化导致的生物多样性丧失和生态系统功能退化是科学界和社会共同关注的首要问题。生态系统可能对土地利用集约化呈现非线性响应，这将带来管理选项，既能减少生态损失，又能实现可观的经济收益。然而，量化不同管理选项下生态损失和社会经济权衡的多学科研究却很少见。在此，我们利用关于9种动植物类群的物种丰富度、6种相关生态系统功能以及农林业扩张的社会经济驱动因素的数据，评估了印度尼西亚苏拉威西岛可可农林业中相互对立的土地利用策略。过去二十年里，可可种植面积扩大了230%，这不仅是由经济市场机制引发的，还受到了很少被考虑的文化因素的影响。从近乎原始森林向农林业的转变对总体物种丰富度影响不大，但植物生物量和碳储量减少了约75%，依赖森林的物种的物种丰富度减少了约60%。相比之下，可可农林业中土地利用强度的增加，以及遮荫树覆盖率从80%降至40%，仅导致生物多样性发生了微小的定量变化，并维持了较高水平的生态系统功能，同时农民的净收入翻了一番。然而，无遮荫系统的收入进一步增加了约40%，这意味着当前对新的集约化做法的经济激励和文化偏好使有遮荫的系统面临风险。我们得出结论，低遮荫农林业在经济力量和生态需求之间提供了最佳的折衷方案。对遮荫种植作物的认证计划可能提供一种基于市场的机制，以减缓当前的集约化趋势。
