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

在未能实现气候目标和失败的技术修复之后，“基于自然的解决方案”(NBS)的概念已成为气候政策中一个重要的替代方案。据预测，到2030年，森林增长可以提供所需气候行动的三分之一，这将导致企业部门以及许多国家政府高调支持森林增长。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，并打算通过种植树木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宣布了万亿棵树运动，基于到本十年末在全球种植1万亿棵树的计划。尽管这些举措受到广泛欢迎，但风险很大。特别是，它们实现预期效益的潜力没有得到严格评估，导致对可靠性和成本效益的担忧。事实上，以前的许多植树或重新造林计划都失败了，似乎是因为它们对疾病预防、供水、种子传播和病虫害防治等因素关注较少，所有这些因素都可以在生物多样性水平较高的自然系统中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促进植树计划、农林和人工林的积极成果方面的作用。为了实现这一点，学生将专注于欧洲、非洲和南美现有研究系统中已发布和未发布的数据集。他们将评估自然植被和生物多样性的景观水平变化对种子传播、授粉、病虫害防治以及树苗的招募和生长的影响，包括与手工种植系统的比较。种子散播鸟类和树木果实的特性分别通过Tobias实验室全球特性数据库和Try植物特性数据库获得，从而可以调查特性多样性、营养水平之间的特性匹配及其对重新造林的影响。第二个主题将侧重于评估生物多样性在调节害虫和传粉者种群方面的作用。学生将在实验室对每个研究地点的访花昆虫和主要食虫鸟类的粪便样本进行元编码，并利用这些样本建立互动网络。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(木材或农作物)。这些成果将增进对将基于生物多样性的复原力建设为多功能景观的最佳做法的理解，这是确保国家统计局能够发挥其潜力，同时应对气候和生物多样性危机，同时也有助于可持续经济发展的关键一步。

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 To achieve this, the student will focus on published and unpublished datasets from established study systems in Europe, Africa and South America.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.