Abstract The Paris Agreement to keep global temperature increase to well-below 2 °C and to pursue efforts to limit it to 1.5 °C requires to formulate ambitious climate-change mitigation scenarios to reduce CO2 emissions and to enhance carbon sequestration. These scenarios likely require significant land-use change. Failing to mitigate climate change will result in an unprecedented warming with significant biodiversity loss. The mitigation potential on land is high. However, how land-based mitigation options potentially affect biodiversity is poorly understood. Some land-based mitigation options could also counter the biodiversity loss. Here we reviewed the recently scientific literature to assess twenty land-based mitigation options that are implemented in different mitigation pathways to comply with the Paris Agreement for their biodiversity impacts by using the Mean Species Abundance (MSALU) indicator for land use. We showed the likely land-use transition and potential MSALU changes for each option, compared their carbon sequestration opportunities (tC per ha) and assessed the resulting biodiversity change in two case scenarios. Our results showed that most options benefit biodiversity. Reforestation of cultivated and managed areas together with restoration of wetlands deliver the largest MSALU increases, if land is allowed to reach a mature state over time. A quarter of the assessed options, including intensification of agricultural areas and bioenergy with carbon capture and storage, decreased MSALU. Options, such as afforestation and reduced deforestation, either positively or negatively affected MSALU. This depends on their local implementation and adopted forest-conservation schemes. Comparing the different options showed that avoiding deforestation by implementing agroforestry at the expense of pastures delivered both the largest MSALU increases and the highest carbon sequestration opportunities. However, agroforestry that leads to deforestation, enhanced carbon sequestration slightly but with a marginal MSALU increase. This stresses the importance of avoiding forest conversion. Our study advances the understanding on current and future benefits and adverse effects of land-based mitigation options on biodiversity. This certainly helps biodiversity conservation and determines the regions with large land-based mitigation potential.

中文翻译：

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评估陆上减缓对生物多样性的影响

摘要 《巴黎协定》将全球温度升高控制在远低于 2 °C 并努力将其限制在 1.5 °C，需要制定雄心勃勃的气候变化减缓情景，以减少二氧化碳排放并加强碳封存。这些情景可能需要重大的土地利用变化。未能缓解气候变化将导致前所未有的变暖，并导致生物多样性的显着丧失。陆地上的减缓潜力很大。然而，人们对基于陆地的减缓方案如何潜在地影响生物多样性知之甚少。一些基于陆地的缓解方案也可以应对生物多样性的丧失。在这里，我们回顾了最近的科学文献，以通过使用平均物种丰度 (MSALU) 指标来评估在不同缓解途径中实施的 20 种陆基缓解方案，以遵守《巴黎协定》对土地利用的生物多样性影响。我们展示了每个选项可能的土地利用转变和潜在的 MSALU 变化，比较了它们的碳固存机会（tC 每公顷），并评估了两种情况下由此产生的生物多样性变化。我们的结果表明，大多数选择都有利于生物多样性。如果允许土地随着时间的推移达到成熟状态，则耕地和管理区域的重新造林以及湿地的恢复会带来最大的 MSALU 增加。四分之一的评估选项，包括集约化农业区和生物能源与碳捕获和储存，降低了 MSALU。诸如植树造林和减少森林砍伐等选项对 MSALU 产生了积极或消极的影响。这取决于他们在当地的实施和采用的森林保护计划。比较不同的选择表明，通过以牺牲牧场为代价实施农林业来避免森林砍伐，既带来了最大的 MSALU 增长，也带来了最高的碳固存机会。然而，导致森林砍伐的农林业略微增强了碳固存，但 MSALU 略有增加。这强调了避免森林转化的重要性。我们的研究促进了对基于陆地的减缓方案对生物多样性的当前和未来收益和不利影响的理解。