Developers are often required by law to offset environmental impacts through targeted conservation actions. Most offset policies specify metrics that are used to calculate offset requirements, usually assessing vegetation condition or quality. Despite widespread use, there is little evidence to support the effectiveness of vegetation-based metrics for ensuring biodiversity persistence. Here, we compared performance of several commonly used metrics by simulating development and restoration within the Hunter Region of New South Wales, Australia. We measured development impacts and offset requirements using four metrics: 1) area only; 2) vegetation condition only; 3) area x habitat suitability, 4) condition x habitat suitability. We simulate development and subsequent offsetting through restoration within a virtual landscape, linking simulations to population viability models for three species; the squirrel glider (Petaurus norfolcensis), the powerful owl (Ninox strenua) and the northern brown bandicoot (Isoodon macrourus). Our results show that 1) gains in suitable habitat did not translate through to species persistence. No net loss could be achieved when performance of offsetting was assessed in terms of amount of suitable habitat, but not when outcomes were assessed in terms of persistence; 2) Maintenance of persistence was more likely when impacts were avoided, giving further support to better enforce the avoidance stage of the mitigation hierarchy; 3) When developments do impact areas of high suitability for species, it is essential that species are explicitly accounted for in the offset, rather than just vegetation or habitat alone. Declines due to a failure to account directly for species population dynamics and connectivity may overshadow the benefits delivered by producing large areas of suitable habitat; 4) Our modelling framework with just three species showed that the benefits delivered by offsets are species-specific, such that implementing offsets will be much more challenging in reality where multiple species need to be considered. Article Impact statement: It is important to use offset metrics that account for the impacts of development on long-term species persistence. This article is protected by copyright. All rights reserved.

中文翻译：

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在选择栖息地破坏的补偿时，量化基于植被的指标对物种持久性的影响

法律通常要求开发商通过有针对性的保护行动来抵消环境影响。大多数补偿政策指定用于计算补偿要求的指标，通常用于评估植被状况或质量。尽管广泛使用，但几乎没有证据支持基于植被的指标在确保生物多样性持久性方面的有效性。在这里，我们通过模拟澳大利亚新南威尔士州亨特地区的开发和恢复来比较几个常用指标的性能。我们使用四个指标来衡量发展影响和抵消要求：1) 仅面积；2) 仅植被条件；3) 面积 x 栖息地适宜性，4) 条件 x 栖息地适宜性。我们通过在虚拟景观中的恢复来模拟开发和随后的抵消，将模拟与三个物种的种群生存力模型联系起来；松鼠滑翔机 (Petaurus norfolcensis)、强大的猫头鹰 (Ninox strenua) 和北部棕袋狸 (Isoodon macrourus)。我们的结果表明 1) 合适栖息地的收益并没有转化为物种的持久性。当根据适宜栖息地的数量评估抵消绩效时，无法实现净损失，但如果根据持久性评估结果，则无法实现；2) 避免影响时更有可能保持持久性，从而进一步支持更好地执行缓解等级的避免阶段；3) 当开发确实影响了物种高度适宜的区域时，必须在补偿中明确考虑物种，而不仅仅是植被或栖息地。由于未能直接考虑物种种群动态和连通性而导致的下降可能会掩盖通过生产大面积合适栖息地所带来的好处；4) 我们仅包含三个物种的建模框架表明，抵消所带来的收益是特定于物种的，因此在需要考虑多种物种的现实中，实施抵消将更具挑战性。文章影响声明：重要的是使用补偿指标来说明发展对长期物种持久性的影响。本文受版权保护。版权所有。4) 我们仅包含三个物种的建模框架表明，抵消所带来的收益是特定于物种的，因此在需要考虑多种物种的现实中，实施抵消将更具挑战性。文章影响声明：重要的是使用补偿指标来说明发展对长期物种持久性的影响。本文受版权保护。版权所有。4) 我们仅包含三个物种的建模框架表明，抵消所带来的收益是特定于物种的，因此在需要考虑多种物种的现实中，实施抵消将更具挑战性。文章影响声明：重要的是使用补偿指标来说明发展对长期物种持久性的影响。本文受版权保护。版权所有。