FAPESP - Restoring Neotropical dry ecosystems - is plant functional composition the key to success?

尽管TDF具有全球重要性和保护不力，但与其他热带森林生态系统，特别是正在恢复的TDF地区相比，对TDF的研究要少得多。我们的目标是解决最近发现的这一知识差距，目的是提高TDF恢复的成功率。该项目将对现有和恢复的TDF对气候变化和极端气候的适应能力进行第一次评估，方法是对决定恢复的TDF地点的植物水分利用、碳生产和养分利用战略的特征进行全面的、社区规模的评估。该项目产生的信息将改变我们目前对恢复的和自然的TDFS场地的功能的理解，促进开发最先进的植被模型，通过与负责制定和实施巴西恢复战略的主要利益攸关方整合，改进气候预测和制定新的恢复政策。我们的主要目标是：目标1：评估采用不同战略恢复的热带森林保护区的生态系统功能。目标2：了解气候变化和气候极端对热带森林保护区的压力。目标3：与巴西政府合作，改善热带森林保护区的恢复和长期恢复战略。热带干燥森林和稀树草原(TDF)占巴西陆地面积的34%，包含巴西50%的植物物种。超过1亿人生活在巴西的TDF地区，其中许多人来自农村脆弱社区，他们依赖TDF提供的基本生态系统服务。这些服务包括：1.巴西农业前沿的供水、遮荫和授粉者；2.国家水安全，亚马逊河外43%的地表水进入TDF，供应巴西三大河流流域的含水层；3.木材和食物的来源；4.缓解气候变化的碳储存；5.自然风景区，广泛用于旅游业；6.4500种木本植物的活种子库，其中许多是地方性的。尽管如此，TDF的保护仍然很差，只有1.2%的干燥森林和7.5%的热带草原处于保护区内，巴西10%的干燥森林和20%的热带草原完好无损。巴西政府认识到目前TDF损失率对社会、经济和环境的影响，承诺到2030年恢复12万平方公里(约占英国一半的面积)的自然生态系统，重点是TDF。巴西环境部(ICMBio)和农业部(EMBRAPA)已经开始实施这一恢复计划。然而，恢复的TDFS地区的成功率仍然很低，不同恢复战略的地区之间的可变性很高。战略成功率低、可变性高的原因尚不清楚，这阻碍了目前实现国家恢复目标的能力。到目前为止，所有的TDFS恢复战略都侧重于重新创造在自然、未受干扰的TDFS生境中观察到的物种组成。这种关注假设物种多样性是最大化生态系统生产力和抵抗气候变化的同义词，但它忽视了这些物种对它们在退化景观中经历的新的更干燥和干扰的环境的适应性。来自热带雨林的最新研究广泛地表明，只关注物种的多样性太狭隘了。相反，植物资源利用战略，特别是水力功能特征，很可能是决定生态系统规模功能以及TDFS生态系统对当前和未来气候变化的抵抗力和复原力的关键。因此，为了成功地保护和恢复森林生态系统，必须解决目前对森林生态系统功能和植物资源利用战略缺乏了解的问题。

Despite their global importance and poor protection, TDFS have been studied far less than other tropical forest ecosystems, particularly TDFS areas undergoing restoration. We aim to address this recently identified knowledge gap with the aim of improving the success of TDFS restoration. This project will provide the first assessment of the resilience of existing and restored TDFS to changing climate and climate extremes, through undertaking a comprehensive, community-scale assessment of traits which determine plant water-use, carbon production and nutrient-use strategies across restored TDFS sites. The information generated in this project will create a step-change in our current understanding of the function of restored and natural TDFS sites, facilitating development of state-of-the art vegetation models to improve climate prediction and the creation of new restoration policy through integrating with key stakeholders responsible for the creation and implementation of restoration strategies for Brazil. Our key aims are:Aim 1: Evaluate ecosystem function in TDFS sites restored using different strategies.Aim 2: Understand the pressures on TDFS from climate-change and climate extremes.Aim 3: Improve policy and restoration strategies for the restoration of, and long-term resilience of TDFS in collaboration with the Brazilian government.Tropical dry forests and savannas (TDFS) make up 34% of Brazil's land area and contain >50% of Brazil's plant species. More than 100 million people live in TDFS regions of Brazil and many of these people are from rural vulnerable communities who rely on essential ecosystem services TDFS provide. These services include: 1. water supply, shade and pollinators for Brazil's agricultural frontier; 2. national water security, with 43% of the surface water outside the Amazon falling in TDFS and supplying the aquifers which feed Brazil's three largest river basins; 3. a source of timber and food; 4. carbon storage for climate change mitigation; 5. areas of natural beauty, used extensively for tourism; 6. a living seed bank for >4500 woody plant species, many of which are endemic. Despite this, TDFS remain poorly protected with only 1.2% of dry forests and 7.5% of savannas in protected reserves and <10% of Brazil's dry forest and <20% of its savannahs remaining intact. Recognising the social, economic and environmental implications of the current rates of loss of TDFS, the Brazilian government has responded by committing to restoring 120,000 km2 (an area about half the UK) of natural ecosystems by 2030, with a focus on TDFS. Brazil's Ministry for the Environment (ICMBio) and Ministry for Agriculture (EMBRAPA) have started implementing this restoration plan. However, success rates of restored TDFS areas remains very low, with high variability between areas subjected to varying restoration strategies. The reasons for low success and high variability between strategies remains unknown, hampering current ability to meet national restoration targets. Until now, all TDFS restoration strategies have focused on re-creating the species composition observed in natural, undisturbed TDFS habitats. This focus has assumed that species diversity is synonymous with maximizing ecosystem productivity and resistance to climate variability, yet it ignores the suitability of these species to the new drier and disturbed environment they experience in degraded landscapes. The latest research from tropical rainforests broadly suggests that focusing only on species' diversity is too narrow. Instead, plant resource use strategies, and particularly hydraulic functional traits are likely to be the key to determining ecosystem-scale function and the resistance and resilience of TDFS ecosystems to current and future climate variability. To successfully protect and restore TDFS it is therefore vital that the current lack of understanding about ecosystem function and plant resource-use strategies in TDFS is addressed.