Disentangling environmental change in the Amazon: vegetation responses to Holocene drivers in the Yasuni National Park, Ecuador.

亚马逊因其高水平的生物多样性及其从地方到全球范围提供的生态服务的重要性而得到广泛认可。然而，我们今天看到的热带森林是由气候条件和地貌变化等长期过程形成的。了解这些森林如何对过去的扰动作出反应，可以揭示有关生态系统恢复力和脆弱性的重要信息，这些信息可以在我们展望未来的环境变化时应用。因此，古生态学研究对于预测热带森林对干扰的反应和为保护工作的规划提供信息至关重要。该项目旨在描述整个全新世亚马逊西部低地森林植被的性质和组成，并调查气候条件、当地水文和人为影响的变化程度。当地水文对低地森林长期动态的影响，特别是河流迁移的影响，迄今为止在这个新构造活跃地区进行的古生态研究中几乎没有探讨过。同样，人类活动的范围及其对森林群落结构和组成的影响仍然是整个大亚马逊地区争论不休的主题。将对厄瓜多尔亚苏尼国家公园的现代样本和沉积记录进行花粉分析，以重建当地的植被历史。这种方法将通过进一步的分析加以补充，包括：(1)生物标志物，这将有助于揭示气候历史；(2)木炭分析，用于建立火灾历史；(3)利用x射线荧光（XRF）和发光测年（OSL）研究当地水文变化的影响；(4)通过光学卫星和无人机进行遥感，这将提供与当前景观动态的联系。一旦建立了古记录，收集到的信息将用于为亚苏尼国家公园绘制未来的轨迹，以协助未来的保护工作。背景：环境变化是一个全球性的现象，了解生物群的反应是至关重要的。热带南美洲拥有一些最具生物多样性的生态系统，因此需要长期的植被动态研究来了解这些全球重要但研究不足的地区的功能和保护。此外，最近观察到的人类活动在某些地区可能在塑造当前景观和多样性方面发挥了关键作用，这在分析面临扰动的特定生态系统的复原力时可能很重要。目的：本项目旨在研究亚苏尼国家公园（厄瓜多尔）亚马孙森林的长期动态。主要目标是：1。描述了全新世亚马逊河西北部低地森林植被的性质和组成，揭示了当前景观建立的开始日期和环境条件。2. 建立火灾历史、气候条件和沉积环境，包括河流影响。3. 评估全新世(i)气候变化、（ii）河流迁移或（iii）人类影响导致亚马逊森林内植被变化的数量。4. 利用这些古特征来绘制国家公园未来的发展轨迹。新颖性：包括花粉（植被）、非花粉孢谱（土地利用）、木炭（火灾）、XRF（侵蚀）、OSL（运输）和生物标志物（降水）在内的代用物的新组合在热带地区是前所未有的，并将产生一个能够提供面对环境变化的长期植被动态的开创性见解的数据集。除了广泛的实验室和计算机技术，环境技能将通过实地工作扩大。

Amazonia is widely recognized for its high levels of biodiversity and the importance of the ecological services it provides from local to global scales. The tropical forests we see today, however, have been shaped by long term processes such as changing climate conditions and geomorphology. Understanding how these forests have responded to past perturbations can reveal important information regarding ecosystem resilience and vulnerability which can be applied as we look towards future environmental change. Palaeoecological studies, therefore, are crucial to forecasting tropical forest response to disturbance and to inform planning of conservation efforts. This project aims to characterize the nature and composition of vegetation in lowland forests of western Amazonia throughout the Holocene and to investigate the extent to which changes can be attributed to shifts in climatic conditions, local hydrology, and anthropogenic influence. The impact of local hydrology on long-term lowland forest dynamics, especially that of river migration, has barely been explored in the palaeoecological studies performed to date in this neotectonically active region. Similarly, the scope of human occupation and its consequential impact on forest community structure and composition remains the subject of contentious debate throughout greater Amazonia. Pollen analysis will be conducted on modern samples and sedimentary records from the Yasuni National Park in Ecuador to reconstruct the local vegetational history. This approach will be complemented by further analyses, including: (1) biomarkers, that will assist in unravelling climate history; (2) charcoal analysis, that will be employed to establish fire history; (3) X-Ray fluorescence (XRF) and luminescence dating (OSL) that will be utilized to investigate the impact of changes in local hydrology; and (4) remote sensing via optical satellites and drones which will provide a link to current landscape dynamics. Once the palaeo record has been established, the information gathered will be used to chart future trajectories for the Yasuni National Park to assist in future conservation efforts. BACKGROUND: Environmental change is a global phenomenon for which understanding thebiota responses is essential. Tropical South America holds some of the most biodiverseecosystems, so long-term vegetation dynamics' studies are needed to understand the functioning and conservation of these globally important and under-studied areas. Moreover, lately observed human occupation may have played in some areas a key role in shaping the current landscapes and diversity, which might be important when analysing the resilience of a given ecosystem in facing perturbations. OBJECTIVES: The project aims to study the long-term dynamics of Amazonian forests in the Yasuni National Park (Ecuador). Main objectives are to:1. Characterize the nature and composition of vegetation on the lowland forests in north-western Amazonia during the Holocene unravelling the onset dates and environmentalconditions of the current landscape establishment. 2. Establish fire history, climate conditionsand depositional environment including fluvial influence. 3. Assess the amount of vegetation change within Amazonian forests as a result of Holocene (i) climate change, (ii) river migration, or (iii) human influence. 4. Using the palaeo signatures to try and chart future trajectories for the National Park. NOVELTY: The novel combination of proxies including pollen (vegetation), non-pollen palynomorphs (land-use), charcoal (fires), XRF (erosion), OSL (transportation) and biomarkers (precipitation) is unprecedented in the tropics and will generate a dataset capable of providing pioneer insights on long-term vegetation dynamics facing environmental changes. Besides a wide range of lab and computer techniques,environmental skills will be enlarged by fieldwork.