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

亚马逊河流域因其高度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承认。然而，我们今天看到的热带森林是由长期过程形成的，例如气候条件和地貌的变化。了解这些森林如何应对过去的扰动，可以揭示有关生态系统复原力和脆弱性的重要信息，这些信息可以应用于我们展望未来的环境变化。因此，古生态研究对于预测热带森林对干扰的反应和为养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河流域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。当地水文对长期的低地森林动态，特别是河流迁移的影响，几乎没有被探讨在古生态研究中进行的新构造活动区。同样，人类占领的范围及其对森林社区结构和组成的影响仍然是整个大亚马逊地区有争议的辩论主题。将对来自厄瓜多尔亚苏尼国家公园的现代样本和沉积物记录进行花粉分析，以重建当地的植被历史。这一方法将得到进一步分析的补充，包括：（1）生物标志物，这将有助于揭示气候历史;（2）木炭分析，这将用于确定火灾历史;（3）X射线荧光和发光测年，这将用于调查当地水文变化的影响;以及（4）通过光学卫星和无人驾驶飞机进行遥感，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绘制亚苏尼国家公园未来的轨迹，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，了解生物区系的反应是必不可少的.热带南美洲拥有一些最具生物多样性的生态系统，因此需要进行长期的植被动态研究，以了解这些全球重要和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，这在分析特定生态系统面对扰动的复原力时可能很重要。目的：该项目旨在研究亚苏尼国家公园（厄瓜多尔）亚马逊森林的长期动态。主要目标是：1.描述全新世亚马逊西北部低地森林植被的性质和组成，揭示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.评估由于全新世（i）气候变化，（ii）河流迁移或（iii）人类影响而导致的亚马逊森林内植被变化量。4.利用古生物的特征来绘制国家公园未来的轨迹。新奇：包括花粉（植被），非花粉palynomorphs（土地利用），木炭（火灾），XRF（侵蚀），OSL（运输）和生物标志物（降水）在内的代理的新组合在热带地区是前所未有的，并将生成一个能够提供长期植被动态面临环境变化的先驱见解的数据集。除了广泛的实验室和计算机技术，环境技能将通过实地考察扩大。

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.