Reassessing the forest impacts of protection The challenge of nonrandom location and a corrective method
Reassessing the forest impacts of protection The challenge of nonrandom location and a corrective method
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DOI：
10.1111/j.1749-6632.2009.05162.x
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发表时间：
2010-01-01
期刊：
影响因子：
--
通讯作者：
Pfaff, Alexander
中科院分区：
文献类型：
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作者：
Joppa, Lucas;Pfaff, Alexander
保护区是减缓全球物种丧失的主要工具，并且似乎在气候变化政策中也发挥着作用。了解它们对森林砍伐的影响可为环境政策提供信息。考虑到实证评估的三个障碍，我们回顾了评估保护对森林砍伐影响的几种方法，并指出经济影响评估中的“匹配”技术可以解决这些障碍。主要障碍源于保护区在景观中非随机分布的事实。非随机位置可能是有意的，并且有充分的理由，包括生物学和政治方面的理由。然而即便如此，当保护区的位置偏向受威胁较小的地区时，许多影响评估方法都会高估保护的效果。匹配技术的使用允许人们在推断保护的影响时控制已知的景观偏差。匹配的应用表明，森林保护的影响估计值比其他方法低得多。然而，现有公园的估计影响的减少并不意味着保护措施无法减少清理。相反，它表明了不同地点的差异对于保护可能对森林砍伐率产生多大影响的重要性。然后，将改进的保护平均影响估计与新公园影响最大的地方的指导捆绑在一起。虽然许多因素将决定未来新保护区的选址，但我们认为，不同空间的保护变化对森林砍伐率的影响应该为地点选择提供信息。
Protected areas are leading tools in efforts to slow global species loss and appear also to have a role in climate change policy. Understanding their impacts on deforestation informs environmental policies. We review several approaches to evaluating protection's impact on deforestation, given three hurdles to empirical evaluation, and note that "matching" techniques from economic impact evaluation address those hurdles. The central hurdle derives from the fact that protected areas are distributed nonrandomly across landscapes. Nonrandom location can be intentional, and for good reasons, including biological and political ones. Yet even so, when protected areas are biased in their locations toward less-threatened areas, many methods for impact evaluation will overestimate protection's effect. The use of matching techniques allows one to control for known landscape biases when inferring the impact of protection. Applications of matching have revealed considerably lower impact estimates of forest protection than produced by other methods. A reduction in the estimated impact from existing parks does not suggest, however, that protection is unable to lower clearing. Rather, it indicates the importance of variation across locations in how much impact protection could possibly have on rates of deforestation. Matching, then, bundles improved estimates of the average impact of protection with guidance on where new parks' impacts will be highest. While many factors will determine where new protected areas will be sited in the future, we claim that the variation across space in protection's impact on deforestation rates should inform site choice.