Ecol Appl. 2014 Jun;24(4):617-32. doi: 10.1890/13-0243.1.
Biodiversity offsets are seen as a policy mechanism to balance development and conservation goals. Many offset schemes employ habitat restoration in one area to recreate biodiversity value that is destroyed elsewhere, assuming that recovery is timely and predictable. Recent research has challenged these assumptions on the grounds that restoration implies long time delays and a low certainty of success. To investigate these assertions, and to assess the strength of empirical support for offset policy, we used a meta-analytic approach to analyze data from 108 comparative studies of secondary growth (SG) and old-growth (OG) habitat (a total of 1228 SG sites and 716 OG reference sites). We extracted species checklists and calculated standardized response ratios for species richness, Fisher's alpha, Sorenson similarity, and Morisita-Horn similarity. We modeled diversity change with habitat age using generalized linear models and multi-model averaging, correcting for a number of potential explanatory variables. We tested whether (1) diversity of passively and actively restored habitat converges to OG values over time, (2) active restoration significantly accelerates this process, and (3) current offset policies are appropriate to the predicted uncertainties and time lags associated with restoration. The results indicate that in the best case, species richness converges to OG reference values within a century, species similarity (Sorenson) takes about twice as long, and assemblage composition (Morisita-Horn) up to an order of magnitude longer (hundreds to thousands of years). Active restoration significantly accelerates the process for all indices, but the inherently large time lags, uncertainty, and risk of restoration failure require offset ratios that far exceed what is currently applied in practice. Restoration offset policy therefore leads to a net loss of biodiversity, and represents an inappropriate use of the otherwise valuable tool of ecosystem restoration.
生物多样性补偿被视为一种平衡发展与保护目标的政策机制。许多补偿计划采用在一个地区进行生境恢复的方法，以重建在其他地方被破坏的生物多样性价值，假设恢复是及时和可预测的。最近的研究对这些假设提出了挑战，理由是恢复意味着长时间的延迟和低成功率。为了调查这些说法，并评估对补偿政策的实证支持的力度，我们使用元分析方法分析了 108 项关于次生生长 (SG) 和原始森林 (OG) 生境的比较研究的数据 (共 1228 个 SG 点和 716 个 OG 参考点)。我们提取了物种清单，并计算了物种丰富度、Fisher's alpha、Sorenson 相似性和 Morisita-Horn 相似性的标准化响应比。我们使用广义线性模型和多模型平均法，对多样性随生境年龄的变化进行建模，并校正了许多潜在的解释变量。我们检验了以下假设：(1) 被动和主动恢复的生境的多样性是否随时间推移向 OG 值收敛；(2) 主动恢复是否显著加速了这一过程；(3) 当前的补偿政策是否适合与恢复相关的预测不确定性和时间滞后。结果表明，在最佳情况下，物种丰富度在一个世纪内收敛到 OG 参考值，物种相似性 (Sorenson) 则需要两倍的时间，而群落组成 (Morisita-Horn) 则需要更长的时间（数百年到数千年）。主动恢复显著加速了所有指数的进程，但恢复固有的时间滞后、不确定性和失败风险要求补偿比率远远超过目前在实践中应用的比率。因此，恢复补偿政策导致生物多样性的净损失，代表了对生态系统恢复这一有价值工具的不当使用。
