Abstract Biodiversity offsets are used internationally to compensate for impacts on the environment, but research on the effectiveness of this instrument in conserving biodiversity is scarce. Conservation banking under the US Endangered Species Act is a long established and strictly regulated offsetting program. An analysis of the implementation of this program can hold implications for biodiversity banking anywhere. This paper describes and analyzes the implementation of species and habitat conservation banking in the state of California. First, we identify aspects of effective offset program design and implementation from previously published literature. In a second step, this paper uses empirical evidence from 30 expert interviews to analyze how these aspects are applied in conservation banking. The analysis covers a no net loss policy goal and additionality, equivalence and accounting, uncertainties and ratios, site selection, landscape-scale mitigation planning, advance mitigation, adherence to the mitigation hierarchy, leakage & trade-offs, oversight, transparency and monitoring. The positive attitude of all stakeholders towards conservation banking suggests that the program yields some benefits, but its contribution to species recovery is unclear. Limited standardized metrics reflecting key biodiversity values for species recovery (e.g. habitat size, connectivity, quality) at the impact and bank site are needed to allow for program evaluation. In addition, transparent tracking across impact permit and crediting processes as well as across agencies is necessary. Once implemented and evaluated in California, results could lead to changes in the implementation of the ESA across the US. We reflect the results considering best practice from academic literature and raise questions for future empirical research.

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通过抵消来保护生物多样性？保护性银行的实证研究结果

摘要 国际上使用生物多样性补偿来补偿对环境的影响，但对该工具在保护生物多样性方面的有效性的研究很少。《美国濒危物种法案》下的保护银行是一项长期建立且受到严格监管的补偿计划。对该计划实施情况的分析可以对任何地方的生物多样性银行产生影响。本文描述和分析了加利福尼亚州物种和栖息地保护银行的实施。首先，我们从以前发表的文献中确定了有效的抵消计划设计和实施的各个方面。第二步，本文使用来自 30 位专家访谈的经验证据来分析这些方面如何应用于保护银行业务。该分析涵盖了无净损失政策目标和额外性、等效性和核算、不确定性和比率、选址、景观规模缓解规划、提前缓解、遵守缓解层次结构、泄漏和权衡、监督、透明度和监控。所有利益相关者对保护银行的积极态度表明该计划产生了一些好处，但其对物种恢复的贡献尚不清楚。需要有限的标准化指标来反映影响和银行地点的物种恢复的关键生物多样性价值（例如栖息地大小、连通性、质量），以便进行计划评估。此外，跨影响许可和计入流程以及跨机构的透明跟踪是必要的。一旦在加利福尼亚实施和评估，结果可能会导致整个美国 ESA 的实施发生变化。我们反映了考虑到学术文献中的最佳实践的结果，并为未来的实证研究提出了问题。