Bradford Michael J
Fisheries and Oceans Canada and, School of Resource and Environmental Management Simon Fraser University, Burnaby, BC, V5A-1S6, Canada.
Environ Manage. 2017 Oct;60(4):588-597. doi: 10.1007/s00267-017-0892-6. Epub 2017 May 18.
Biodiversity offset programs attempt to minimize unavoidable environmental impacts of anthropogenic activities by requiring offsetting measures in sufficient quantity to counterbalance losses due to the activity. Multipliers, or offsetting ratios, have been used to increase the amount of offsets to account for uncertainty but those ratios have generally been derived from theoretical or ad-hoc considerations. I analyzed uncertainty in the offsetting process in the context of offsetting for impacts to freshwater fisheries productivity. For aquatic habitats I demonstrate that an empirical risk-based approach for evaluating prediction uncertainty is feasible, and if data are available appropriate adjustments to offset requirements can be estimated. For two data-rich examples I estimate multipliers in the range of 1.5:1 - 2.5:1 are sufficient to account for the uncertainty in the prediction of gains and losses. For aquatic habitats adjustments for time delays in the delivery of offset benefits can also be calculated and are likely smaller than those for prediction uncertainty. However, the success of a biodiversity offsetting program will also depend on the management of the other components of risk not addressed by these adjustments.
生物多样性补偿计划试图通过要求采取足够数量的补偿措施来抵消因人类活动造成的不可避免的环境影响，以平衡该活动所导致的损失。乘数或补偿比率已被用于增加补偿量，以应对不确定性，但这些比率通常是基于理论或临时考虑得出的。我在淡水渔业生产力影响补偿的背景下，分析了补偿过程中的不确定性。对于水生生境，我证明了基于风险的实证方法来评估预测不确定性是可行的，并且如果有数据可用，可以估计对补偿要求的适当调整。对于两个数据丰富的例子，我估计1.5:1至2.5:1范围内的乘数足以应对收益和损失预测中的不确定性。对于水生生境，还可以计算补偿效益交付时间延迟的调整，并且可能比预测不确定性的调整要小。然而，生物多样性补偿计划的成功还将取决于对这些调整未涉及的其他风险组成部分的管理。
