Threats to the integrity of biodiverse Amazon floodplain habitats from deforestation, dams, and climate change are increasingly severe but to date, Amazon biodiversity scenarios have not considered these critical environments. Building on decades of floodplain-focused research in the Amazon by consortium members, we will improve characterization of Amazonian whitewater floodplain habitats and inundation dynamics, allowing us to 1) scale up existing fish, floodplain forest, and phytoplankton biodiversity datasets, 2) evaluate the potential impacts of regional drivers such as climate, land use change, and dams on floodplain habitats, and 3) engage at local and regional scale a large panel of stakeholders in looking for sustainable strategies for wetlands preservation. The scenarios produced at both scales will be compared in terms of wetlands conservation and biodiversity descriptors including Essential Biodiversity Variables and Sustainable Development Goals indicators. Our study framework focusing on the floodplains of the mainstem Amazon river (Brazil and Colombia) and Juruá river (Brazil) allows comparison between whitewater floodplain sites contrasting greatly in terms of floodplain geomorphology, land use and management history, commercial fishing pressure, and human population density. Innovative aspects of our work include 1) testing a remote-sensing-based approach for mapping phytoplankton biodiversity in floodplain lakes; 2) use of new satellite data to greatly increase the spatiotemporal resolution of floodplain habitat and inundation maps; 3) use of environmental eDNA metabarcoding to examine the distribution and relative abundance of phytoplankton, zooplankton, and fish in floodplain lakes; 4) individual-based modeling of Lévy-flight fish foraging patterns across a network of oxbow lakes; and 5) nested-scale agent-based participatory models to develop scenarios. The proposed work will greatly expand available information for decision-making to support the vast biodiversity and extensive ecosystem services provided by Amazon whitewater floodplains.

Due to an increasing demographic pressure, the Metropolitan Region of Recife (RMR, the fifth largest metropolitan area in Brazil), went through remarkable water and land use changes over the last decades. These evolutions gave rise to numerous environmental consequences, such as a dramatic decline of the piezometric levels, groundwater salinization and contamination. This degradation of natural resources is linked to the increase of water demand, punctually amplified by drought periods which induced the construction of thousands of private wells, hindering global political solutions. The RMR thus appears as a typical "hot spot" illustrating the problems of emerging countries such as urbanization, unequal distribution of wealth, limited effects of political decisions, rapid industrial and touristic development. All these factors induce high pressures on water resources both on quantity and quality in the context of global social and environmental changes. Under these conditions, the COQUEIRAL project proposes an interdisciplinary research program aiming to study the human impact on coastal overexploited aquifers. The project is structured in three principal converging axes: (1) the analysis of pressures on the groundwater resources and their societal and structural reasons, (2) the identification of sources and mechanisms of groundwater quality and quantity degradation, focusing on the physical and chemical processes as vectors of the reaction of the system to the external pressures and (3) the assessment of the regional impact of global changes on water ressources. COQUEIRAL will approach the degradation of the groundwater resources by questioning the specific conditions of urbanization and water administration in Recife at multiple levels: the macro-sociological level with the political and institutional stake of water management; the meso-sociological level with the water’s collective stakes and their perceptions; and the micro-sociological level, meaning the representations, practices, individual and collective uses of water. Geomorphological-urban maps will complete the knowledge. In parallel to the acquisition of new geological, hydrological and hydrogeological data, COQUEIRAL will elaborate methods to determine the origin and processes of salinization, including a multi-tracer approach, to identify sources and pathways of inorganic contamination. and to determine the residence time of water within the aquifer system. Based on the gained knowledge, hydrogeological conceptual and 3D numerical models of the functioning of the aquifer system in its social and environmental contexts will be developed. In the aim to improve existing management tools, COQUEIRAL will propose the outlines for best practices, based on scenarios of groundwater resources evolution resulting from the sociological and climatic scenarios developed in the project. Knowing the outstanding importance of water resources management for the regional development, COQUEIRAL will share the results of this interdisciplinary work with all relevant stakeholders, through a variety of communication networks, including a photographic exhibition. The results obtained in the specific framework of the metropolitan region of Recife are in great part transposable to similar contexts of "hot spots" of human and climatic pressure on water resources in emerging countries. At French level, the project also involves a SME (Geo-Hyd) and will serve as a example for future collaborations with regional enterprises at an international scale. The project has applied for labeling by the “pôle de compétitivité” DREAM.

The Amazon rainforest contains 40% of all remaining tropical rainforest in the world, but has seen rapid deforestation since the 1960s, and as much as 40% of the Brazilian Amazon could be deforested by 2050. Land-use change is an important man-made driver of climate change. We know that deforestation will generally make the atmosphere both warmer and drier, but how these changes will affect rainfall is more complex. Climate models mostly predict that deforestation will reduce rainfall, but the amount varies from 0 to 60% across different studies. Climate models use grid boxes of 10s to 100s km, which are much larger than a typical cloud. While cloud properties can be estimated from the conditions in the grid box, calculating the amount of rainfall is very uncertain, especially in the tropics. One solution is to run a model with much smaller grid boxes, but focusing on a small region, so that clouds and the detailed deforestation patterns found in the Amazon can be represented explicitly. These studies show that the surface patterns alter local weather patterns, increasing rainfall over the deforested patches, which contradicts climate models. However, because these studies focus on smaller regions, we do not know if these local effects are important for the water cycle of the entire Amazon. This project will combine both approaches, using the increased computing power now available to simulate, for the first time, the entire Amazon basin while also explicitly representing clouds. This is a crucial improvement, because past studies have shown that resolving clouds leads to a complete change in model behaviour, greatly improving how tropical rainfall is represented, including climate extremes like flooding and droughts which have the most impact on local populations. We will use these simulations to investigate how increasing deforestation will affect rainfall over the Amazon, and how these changes compare to those caused by global climate change driven by increasing carbon dioxide levels. The project is particularly exciting because it will provide a comprehensive understanding of how deforestation affects rainfall, simulating both changes in regional climate and the local weather patterns within it which directly affect people. Tropical rainfall is a key area of research in climate modelling, because although it is the most important climatic parameter to end users, it is also the most uncertain. For example rainfall drives a number of economic sectors such as agriculture and hydroelectric power, and while deforestation is used to clear land for agriculture, reductions in rainfall could reduce the yield per hectare, negating any economic gain from increasing the agricultural area. Patterns of deforestation can also affect where it rains, which could help planners identify ways to mitigate some of the negative effects on the remaining forest. This project will engage with stakeholders in the region through workshops to improve our physical understanding in a targeted way to address global challenges which have direct relevance to many people.