Evaluating the role of biodiversity in delivering sustainable nature-based solutions to climate change

在错过气候目标和失败的技术修复之后，“基于自然的解决方案”（NbS）的概念已经成为气候政策中的一个重要替代方案。据预测，到2030年，森林增长可以提供三分之一的气候行动需求，这导致企业部门以及许多国家政府的高调认可。根据波恩挑战，62个国家承诺恢复1.7亿公顷被砍伐或退化的土地，并打算通过植树造林来履行这些承诺的近一半。在更大的规模上，2020年达沃斯世界经济论坛上宣布了“植树造林运动”，计划到2020年在全球种植1万亿棵树。尽管这些举措受到广泛欢迎，但也存在风险。特别是，它们实现预期效益的潜力尚未得到严格评估，导致对可靠性和成本效益的关切。事实上，以前的许多植树造林或重新造林方案都失败了，似乎是因为它们很少注意疾病预防、供水、种子传播和虫害控制等因素，而在生物多样性水平高的自然系统中，所有这些都可以以低得多的成本实现。该项目的目标是评估生物多样性在最大限度地提高植树计划、农林业和种植园林积极成果方面的作用。为了实现这一目标，学生将专注于欧洲，非洲和南美洲已建立的研究系统中已发表和未发表的数据集。他们将评估自然植被和生物多样性的植被水平变化对种子传播、授粉、虫害控制以及树苗的补充和生长的影响，包括与手工种植系统进行比较。种子传播鸟类和树木果实的性状可分别通过Tobias实验室全球性状数据集和TRY植物性状数据库获得，从而可以调查性状多样性，营养级之间的性状匹配及其对重新造林的影响。第二个主题将侧重于评价生物多样性在调节害虫和传粉媒介种群方面的作用。学生将在每个研究地点对访花昆虫和主要食虫鸟类的粪便样本进行基于实验室的元条形码编码，并使用这些来构建交互网络。最后，将调查不同管理战略在多大程度上改善社会经济成果，特别侧重于成本效益、碳吸收和产量（木材或作物）。研究结果将提高对在多功能景观中建立基于生物多样性的复原力的最佳实践的理解，这是确保NBS能够发挥其潜力以应对气候和生物多样性危机的关键一步，同时也有助于可持续经济发展。

In the wake of missed climate targets and failed technological fixes, the concept of "Nature-based Solutions" (NbS) has emerged as a prominent alternative in climate policy. It has been forecast that forest growth can provide a third of the climate action needed by 2030, leading to high-profile endorsements in the corporate sector, as well as by many national governments. Under the Bonn Challenge, 62 countries have pledged to restore 170 million ha of deforested or degraded land and intend to meet nearly half of these commitments with tree plantations. At an even larger scale, the Trillion Tree Campaign was announced at the World Economic Forum in Davos, 2020, based on plans to plant a trillion trees worldwide by the end of the decade. Although broadly welcomed, these initiatives are risky. In particular, their potential to deliver the intended benefits has not been rigorously assessed, leading to concerns over reliability and cost-effectiveness. Indeed, many previous tree planting or reforestation programmes have failed, seemingly because they paid little attention to factors such as disease prevention, water supply, seed dispersal and pest control, all of which may be delivered at much reduced cost in natural systems with high levels of biodiversity. The goal of this project is to assess the role of biodiversity in maximising positive outcomes for tree planting schemes, agroforestry and plantation forestry. To achieve this, the student will focus on published and unpublished datasets from established study systems in Europe, Africa and South America. They will assess the effect of landscape-level variation in natural vegetation and biodiversity on seed dispersal, pollination, pest control, and the recruitment and growth of tree seedlings, including comparison with hand-planted systems. Traits of seed dispersing birds and tree fruits are available through the Tobias lab global trait dataset and the TRY plant trait database, respectively, allowing an investigation of trait diversity, trait matching between trophic levels, and their effects on reforestation. A second theme will focus on evaluating the role of biodiversity in regulating populations of insect pests and pollinators. The student will conduct lab-based meta-barcoding of flower-visiting insects and faecal samples from the dominant insectivorous bird species at each study site, and use these to build interaction networks. Finally, the extent to which different management strategies improve socio-economic outcomes will be investigated, with particular focus on cost-effectiveness, carbon uptake and yield (timber or crops). The results will improve understanding of best practices in building biodiversity-based resilience into multifunctional landscapes, a key step towards ensuring that NbS can achieve their potential to tackle both climate and biodiversity crises while also contributing to sustainable economic development.