NERC-FAPESP PhenoChange: Towards a Dry Tropics Global Phenological Monitoring Network

NERC-FAPESP PhenoChange：迈向干燥热带全球物候监测网络

• 批准号: NE/X002993/1
• 负责人: Kyle Dexter
• 金额: $ 10.65万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX002993%2F1
• 关键词: NERC; FAPESP; PhenoChange; Towards; Dry

Phenology is a term used to describe the seasonal timing of animal and plant behaviour. Examples of phenological events are when plants first flower in the spring or when birds migrate to the tropics for the winter. In the dry regions of the tropics, phenological behaviour of plants seems to be primarily linked to water availability, rather than to changes in temperature as for example in temperate areas like the UK, but determinants of tropical phenology are poorly understood. Yet, elucidating the phenological behaviour of plants, including in the dry tropics, is essential to measure the flow of carbon into and out of ecosystems. This contributes in turn to understanding the links between plants and the atmosphere and ultimately to predicting the potential impact of climate change on vegetation and vegetation impacts on the climate.Recent reports from the Intergovernmental Panel on Climate Change and the United Nations Environment Programme have made it clear that more data are needed on the phenological patterns of vegetation in the tropics, in order to improve predictions on the future of the climate, both in the tropics and globally. To do that, we need to study the phenology of tropical vegetation over broad geographic areas. Hypothetically this can be accomplished using satellite observations, but in fact, the data available from satellites are inadequate: clouds often block a space-based view of the vegetation and the spatial resolution of the images is too coarse (imagine a very fuzzy photograph). The latter means that it can be very difficult to distinguish between trees leafing out versus grasses, with important implications for the amount of carbon flowing into or out of an ecosystem. This is particularly relevant in dry tropical regions where mixed ecosystems with trees and grass are widespread. We also have a poor idea of how phenological timing varies over geographic regions with different patterns of rainfall.Ground-based observations of phenology are therefore needed to complement satellite observations and provide a more accurate picture of vegetation behaviour. Historically, ground-based observations have been difficult to implement at a broad geographic scale in a consistent way, because they are labour intensive and difficult to do in a consistent manner. However, new technologies point a way forward to overcome these issues and advance multi-site and multi-layer (tree and grass) observations across tropical regions. Specifically, cameras can be installed that take photographs every day of the same patch of vegetation over the course of months and years. Such images can be efficiently processed using new computational techniques to quantify when a given patch of vegetation, or ecosystem, flushes new leaves, and whether those leaves are on trees or the ground layer.The proposed project, PhenoChange, will link up global experts on camera-based phenological monitoring in Brazil and the USA with a team of British and African scientists that are leading pioneering, ground-based studies of tropical dry vegetation across sub-Saharan Africa. The project team will install and monitor cameras at six representative sites across dry tropical areas in Brazil and sub-Saharan Africa. This will result in the first comparable, ground-based dataset of vegetation phenology in the dry tropics across multiple continents. The research team will analyse these data to address some key unanswered questions around the timing of tree versus grass phenology in tropical dry vegetation and how this varies over gradients of rainfall. The results will have important implications for models that predict future climate change and its interaction with vegetation change. Finally, the results will lay the groundwork for future grant applications that will deepen and expand UK expertise on vegetation in tropical dry ecosystems.

物候学是一个用来描述动物和植物行为的季节性时间的术语。物候事件的例子是植物在春天第一次开花或鸟类迁移到热带过冬。在热带干旱地区，植物的物候行为似乎主要与水的可用性有关，而不是与温度的变化有关，例如在英国等温带地区，但对热带物候的决定因素知之甚少。然而，阐明植物的物候行为，包括在干燥的热带地区，对于测量碳流入和流出生态系统至关重要。这反过来又有助于了解植物与大气之间的联系，并最终有助于预测气候变化对植被的潜在影响以及植被对气候的影响，政府间气候变化专门委员会和联合国环境规划署最近的报告明确指出，需要更多关于热带植被物候模式的数据，以改善对热带和全球气候未来的预测。要做到这一点，我们需要研究广泛地理区域的热带植被的物候。从理论上讲，这可以通过卫星观测来实现，但实际上，卫星提供的数据是不够的：云层往往阻挡了对植被的天基观测，图像的空间分辨率太粗糙（想象一张非常模糊的照片）。后者意味着很难区分树木和草，这对流入或流出生态系统的碳量有重要影响。这一点在干旱的热带地区尤其重要，因为那里树木和草的混合生态系统非常普遍。我们也不太了解不同降雨模式的地理区域的物候时间是如何变化的，因此，需要对物候进行地面观测，以补充卫星观测，并提供更准确的植被行为情况。从历史上看，地面观测一直难以以一致的方式在广泛的地理范围内实施，因为它们是劳动密集型的，难以以一致的方式进行。然而，新技术指出了克服这些问题的前进方向，并推动了热带地区的多站点和多层（树木和草地）观测。具体来说，可以安装摄像机，在几个月和几年的时间里每天拍摄同一片植被。这些图像可以通过新的计算技术进行有效处理，以量化特定植被或生态系统何时会长出新叶，以及这些叶子是在树上还是在地面上。拟议中的项目PhenoChange将把巴西和美国基于相机的物候监测方面的全球专家与英国和非洲科学家团队联系起来，他们是领先的开拓者，撒哈拉以南非洲热带干旱植被的地面研究。项目小组将在巴西和撒哈拉以南非洲干旱热带地区的六个代表性地点安装和监测摄像机。这将产生第一个可比较的，基于地面的多大洲干旱热带植被物候数据集。研究小组将分析这些数据，以解决一些关键的悬而未决的问题，围绕热带干旱植被中树木与草物候的时间以及这如何随降雨梯度而变化。这些结果将对预测未来气候变化及其与植被变化相互作用的模型具有重要意义。最后，研究结果将为未来的赠款申请奠定基础，这将深化和扩大英国在热带干旱生态系统植被方面的专业知识。