Changes in the natural environment are creating large shifts in the animals and plants on which we rely. However, conventional approaches to the monitoring of biodiversity have only provided limited insights into the rate of change and the drivers of that change. Primarily, our current ways of learning about the natural world are held back by an inability to survey regularly, an inability to quantify the number (abundance) or amount (biomass) of organisms, and an inability to survey simultaneously across large areas with consistent methods. The result is that, at a time when we recognise intuitively that there are serious environmental problems, scientists are still struggling even to demonstrate conclusively that those problems exist. Our radar-based biodiversity monitoring approach represents a potential solution to this need for a biological monitoring yardstick. Radar networks have been in place for weather monitoring and forecasting for decades around the world and give high-resolution information about objects (usually rain and snow) in the atmosphere. However, we have demonstrated that weather radars also give useful information about how many animals are present in the air and our project team is applying our novel techniques in this project focused on Brazilian research priorities. Our project has three main research aims, each of which constitutes a novel attempt at answering an old question within the Brazilian environment. First, we will apply our methods to track key crop pests as they move in and out of agricultural landscapes. We have at our disposal to complementary radar technologies - the first the weather radar networks on which our work has been focused and the second a novel radar device created by a Brazilian company that allows local scanning (within a field). The second research aim is to test whether patterns of pesticide application influence our detection of insects. Brazil has experienced a substantial increase in the diversity and abundance of chemical pesticides in the past decade, with largely unknown consequences for biodiversity. Finally, we will use an older form of weather radar that is scanning across the Amazon region of Brazil to explore whether it is possible to extract meaningful biological information about the state of rainforest insect populations. The rainforest analysis is high risk as it may not yield meaningful data due to the age of the radars. However, if there is useful information in the data then our methods could unlock a vast dataset of records of Amazonian biodiversity. The final part of the project focuses on the broader collaboration between the Brazilian and UK parts of our team. The initial contact between the groups was brought about because of a need to exchange ideas and expertise in radar aeroecology. To help meet this need and to establish a way of working between the two communities of researchers, we will create an online training course that will teach the basics of radar science to the ecologists and ecology to the radar scientists such that the field of radar aeroecology is more accessible as it develops. The key project outputs will be a collaborative paper exploring the application of radar biomonitoring to the Brazilian environment, the training course on aeroecological methods, and one or more papers describing the preliminary radar analysis of the agricultural pest, pesticide, and rainforest analysis that we will undertake. We have plans to build our network to deliver radar-based monitoring to other countries and this new collaboration will be an important cornerstone of that wider goal.

The world's rainforests are incredible reservoirs of biodiversity, holding over 60% of the world's animal species and 67% of all tree species. Conserving this remarkable richness is fundamental for the planet's biological integrity. Yet, it is also under threat from a range of human pressures, such as deforestation, the disturbance of the remaining forests by fires or selective logging, as well as climate change that can exacerbate other threats. These threats are prevalent in the world's largest tropical forests, the Amazon. For example, one third of the Amazon has already been cut down or disturbed by forest fires and selective logging. The climate has also changed markedly in the past 40 years, with some regions facing increased temperatures of 2.5 degrees Celsius and marked reductions in rainfall in the dry season. Give the scale and intensity of these changes, it is imperative that we understand how they are affecting the Amazon's diversity. To date, this has been carried out by using satellites and large-scale plot networks to assess changes in carbon stored by trees or the species composition of the forest. We have much less information on rainforest animals, which are not visible from space or airplanes, and are mobile and hard even for humans to detect on the ground. The absence of large-scale and standardised information on rainforest animals means we do not know how human impacts are affecting them at large scales. Our RAINFAUNA project aims to resolves this knowledge gap by using new technologies and methods to make the first Amazon-wide assessment of the density of populations of birds and invertebrates (insects and arthropods). For birds, we focus on the antbirds, a group of understorey species that are emblematic of rainforest fauna. For invertebrates, we focus on species living in the leaf-litter and topsoil. These two groups provide important information for conservation and ecology. Birds are the best-known faunal group, and estimating their densities will allow us to determine population sizes of species for the first time. Understanding invertebrate activities and diversity provides insights into the important functional roles they carry out in the forests, from decomposition of leaves to the mixing of the topsoil. We will use the forest microclimate to understand animal responses to climate change and forest disturbance. The temperature and humidity of the understorey and leaf litter are key to understanding tropical forest fauna, as they describe the conditions experienced by species. We will use sampling to explore this link between microclimate and fauna, using automated recording units to assess tropical fauna at 180 sites. We will also develop our microclimate model so it can map forest temperature and humidity across the basin. This will allow us to understand how the density of birds and activities of insect changes over space. Crucially, we can also explore how microclimate - and therefore the fauna - will change in the future under different scenarios of climate change and forest disturbance.

The overall aim of this project is to determine and communicate the risk of significant change to the Amazon rainforest caused by anthropogenic disturbance and climate change. We will address a fundamental issue of our time, on the likelihood of Amazon rainforest dieback in the 21st century and identify regions that are most susceptible. We will combine this new knowledge with policies and scenarios developed by key stakeholders to co-design a Safe-Operating-Space for Amazonia. To address the iconic issue of Amazon dieback we will advance new ecological understanding of how forests grow, decline and recover following disturbance from climate extremes, forest fire and deforestation and their interaction in the context of 21st Century global warming. We will build novel datasets using a new forest plot network, drones and satellites to produce near-real-time maps of the risk to forests from climate, and track individual large-tree mortality across the basin. Together this information will be used in mathematical models to help estimate the risk of future forest dieback. We will join this work with models used to predict the effects of land use (forest conversion, degradation) on forest function, and the ecosystem services these forests provide to humanity. The outputs will enable us to deliver new information to policy makers regarding future options for land use, helping them to build optimal land use pathways that minimise the risks that may arise out of large-scale forest loss or dysfunction in Amazonia. The Amazon forest plays a vital role in the world's climate. In addition, by annually absorbing 5-10% of human-related CO2 emissions via vegetation growth, the region acts as a large brake on climate change. Climate extremes (eg drought), forest fires and deforestation reverse this process, causing net emissions to the atmosphere. If this were to happen on a large enough scale, via increased forest loss or increased rates of climate change - or their interaction - the resulting positive effect on global CO2 and climate change, would make the already-challenging Paris climate targets virtually impossible. In short, climate change, forest fires and deforestation have been identified as major intensifying and interacting threats to Amazonia. A substantive loss of Amazonian forest, also known as "Amazon dieback", would have huge negative consequences for human well-being, biodiversity, biogeochemical cycling, and regional and global climate. However, the level of global climate change combined with human disturbance that could trigger large-scale dieback is not known. Climate change is predicted to become more intense in the region alongside increases in human-driven deforestation and forest degradation (e.g fires, logging). Their impacts are poorly understood because of a lack of data, and because models cannot currently represent the key processes well enough. We have gathered leading UK and S American scientists in the fields of ecology, ecophysiology, Earth observation (using satellites) and the mathematical modelling of vegetation growth, land-use and climate as applied to Amazonia. We are uniquely positioned to make a step-change in understanding the combined effects of climate stress and human disturbance on Amazonia. Our measurements will build new knowledge about intact and disturbed forests, their stability and the physiology driving their stress responses. These knowledge advances will enable new modelling of forest-climate-land-use interactions which we will use to inform policymakers. We will engage with stakeholders from state to international levels to co-develop land-use scenarios that minimise risk in future climate and forest ecosystem services. Overall, we propose multiple large and integrated advances in empirical and modelling studies of the forests of Amazonia, and will build a science-policy dialogue that delivers significant impact locally, regionally and globally.

SUMMARY The Amazon is the most important biome of South America, harbouring extraordinarily high levels of biodiversity and providing important ecosystems services. This biome is particularly notable for evolving independently from fire and in a moist, warm climate. In recent decades, altered fire regimes and an increasingly hotter and drier climate has pushed this key biome towards ecological thresholds that will likely lead to major losses in biodiversity and ecosystem services. Similarly, the ecotonal forests at the Amazon-Cerrado transition are unique ecosystems in terms of form and function, but they may be the first to suffer large-scale tree mortality and species loss due to the combined effects of increased anthropogenic disturbance, altered fire regimes and a drier climate. Vulnerability of fire and droughts are closely intertwined in Amazonian and transitional forests because fires in this region only occur when there is water stress and a human ignition source. Thus, drought increases vulnerability to fire, but we do not yet understand the magnitude and spatial variation of these vulnerabilities. Once a forest burns there is immediate tree mortality, but recent evidence also shows a significant time-lagged mortality that can last for decades, becoming an important carbon source. However, the mechanistic processes that lead to time-lagged tree mortality in this myriad of forest ecosystems encompassing the Amazon biome and the Amazon-Cerrado transition are still poorly understood. We also lack knowledge on how these processes might vary spatially across the biome and its transition. A better understanding of the mechanisms that lead to tree mortality after fires and droughts is needed to design future policies that emphasise nature-based solutions including restoration and natural regeneration. This proposal presents a multi-level approach that aims at deciphering the mechanisms that underly vulnerability to fire and time-lagged post-fire mortality across the tropical forests in Amazon and Amazon-Cerrado transition. To achieve this aim, we will quantify fire vulnerability at three different scales and link them through an upscaling approach. First, we will identify the ecological mechanisms, reflected through functional traits, that explain why individuals and species die after fires occur. For this, we will focus on poorly understood traits that can be related to fire and/or hydraulic functioning. Second, at the community scale, we will examine how vegetation structure, community traits and microclimate affect the probability to burn, through an intensive characterisation of different vegetation types with multispectral and light detection and ranging (LIDAR) imagery. Third, we will use our our unique ground-dataset on functional traits, vegetation structure and moisture dynamics, and the latest state-of-art remotely sensed information on structure and water stress to predict the vulnerability of the Amazon forests and Amazon-Cerrado transitional forests. This information will be directly applicable for the detection of sensitive hotspots (areas particularly vulnerable to fire) through satellite products. We will deliver quantifiable early-warning metrics of ecosystem vulnerability to fire that can be mapped and incorporated into fire management policies. This is a revised version of a NERC proposal that was rejected with a score of 7 by the NERC Panel in July 2020, and we have carefully addressed the Panel's comments. Specifically, we have clarified the methodology and we have reformulated the hypotheses, so they address vulnerability to fire and not drought fire-interactions.