The increase of international trade in recent decades, as well as insufficient control for the transport of exotic species, have resulted in the accidental introduction of many animal and plant species. One of the most significant ecological impacts of introduced species is predation on native species. Predation can indeed act as a major mechanism of species extinction in invaded communities, affecting as a consequence the whole ecosystem functioning. For instance, the introduction of terrestrial platyhelminthes, recognized as superpredators of soil invertebrate fauna, may represent a threat to earthworms and the numerous ecosystem services that they provide. By significantly modifying the physical, chemical and biological properties of the soil profile; earthworms indeed play a key role in determining the functioning and the biodiversity of the whole ecosystem, as they influence the habitat and activities of many other organisms (plants, animals and micro-organisms). The aims of the PLATWORM project are to delineate, and to predict, the consequences that modifications of earthworm communities, under the effect of a new predation pressure, can have on the functioning of the soil ecosystem, in anthropized environment. In France, the presence of 10 potentially invasive Platyhelminthe species has recently been reported. The most common, Obama nungara, a generalist predator of soil invertebrates, is now present in 70 departments. In the PLATWORM project, a comprehensive approach will be developed for the study of the impact on soil functioning of the presence of this introduced species. Fundamental knowledge on the disturbance of biodiversity and the modification of the functioning of the soil ecosystem following the introduction of this predator will be acquired. To achieve its objective, the PLATWORM project propose an innovative multidisciplinary approach combining mesocosm experiments, metagenomics, community ecology, study of soil properties and participatory science. All the biological, ecological and human-related data that will be produced by the project will allow modeling the impact of terrestrial platyhelminthes on soil functioning. The establishment of a field-validated ecosystem model will allow both a broad understanding of the targeted ecosystem and predicting potential long-term trajectories of ecosystems invaded by O. nungara. This will therefore provide key management guidance for mitigation actions.

The impacts of severe drought events on ecosystem functions are far from being understood, as are the mechanisms which underlie functional resilience after the disturbance has passed. This topic is of utmost importance in tropical regions, where climate change models forecast significant changes in water availability due to increasing frequency and intensity of drought events. Only a handful of studies have examined how drought can affect multiple functions in tropical systems. Because such studies focused on the immediate outcome of drought (ignoring the recovery and resilience trajectories), we don’t know how organism traits and ecological mechanisms mediate the post-drought trajectory of ecosystem functions. Metacommunity theory predicts that immigration from source patches should prevent extinction in sink populations, but we know nothing of how habitat patch size and distance to source populations interactively mediate ecosystem resilience to drought. The aim of RESILIENCE is to understand how different scales of biological organisation, organisms, functional community structure, metacommunity, and their interactions, drive community re-assembly and multifunctional resilience in neotropical ecosystems, following drought events that range from the current norm to extreme events and predictions of the Intergovernmental Panel on Climate Change. Our experiments will be conducted in French Guiana. We will manipulate drought and metacommunity dynamics at the level of an entire, spatially-discrete ecosystem (the natural microcosm formed by rainwater-filled leaves of tank bromeliads and their microbial-faunal communities), to separate the roles of in situ recovery (tolerance, resistance forms) versus immigration on the resilience of key ecosystem functions under different drought scenarios. We define tolerance as physiological ability of current life form (e.g., larvae) to withstand drought, whereas resistance refers to a resting stage (e.g., cysts) to allow the population to persist through the dry spell. Desiccation-rehydration experiments will allow us to partition the contributions of tolerance and resistance to resilience. We will also manipulate habitat patch size and isolation, to examine how the interaction between these factors affect ecosystem resilience. Response variables will account for core functions in most ecosystems: detrital decomposition, photosynthetic activity and microbial respiration, and the simultaneous production of these functions or multifunctionality. We expect that modest drought intensities will be resisted by the in situ tolerance traits of species, but once drought intensifies these physiological thresholds will be exceeded and the system will shift to a degraded state. At this point, continuance of the community will be dependent on recolonization from nearby source patches, and therefore metacommunity configuration will become critical. Our specific hypotheses are: (1) Multifunctionality will shift to alternative states at lower drought intensity if source patches are not available to prevent extinctions; (2) as drought intensity increases, the driving factors underlying ecosystem resilience will shift from organism tolerance to resistance, and from functional community structure to metacommunity dynamics; and (3) once we account for the negative effect of distance from source patches on recolonization rates, larger patches will be more attractive to immigrants and will undergo faster resilience than smaller habitat patches. Our findings will be disseminated to scientists, students, stakeholders, and public schools. If we understand the mechanisms that enhance or undermine multifunctional resilience, we can consider how our results will allow forecasting future responses of ecosystems to drought. RESILIENCE comes at a critical point in research on ecological effects of climate change, and will provide a fresh, synthetic approach on how to predict the ecosystem consequences of climate change.

Tropical forests are currently experiencing huge pressures from global changes. If tropical deforestation has been rightly the focus of much attention these last decades, forest degradation and its consequences in the tropics has been much less studied and quantified. Yet, forest degradation is pervasive throughout the tropics and leads to a significant loss of ecosystem services. Hence, a major issue is the reversibility of degradation. In many cases, natural successional processes are expected to bring back the system to a state similar to the initial one. However, in some cases, the system may have trespassed a threshold and lost its ability to follow such a classical successional pathway; it may remain in a so-called blocked succession or in an alternative degraded stable state. The Marantaceae forests from Central Africa likely correspond to such stable degraded systems. They cover very large areas in Central Africa and have a very low density of trees with a dense understory composed of giant herbs. The few studies on Marantaceae forests suggest that their large patches (up to 2000 km2) are likely to have originated from old disturbances (>1000 years ago) and have been maintained over long periods through positive feedback mechanisms, e.g. inhibition of tree regeneration by giant herbs. Observations also suggest that current human disturbances, such as logging activities, as well as climate anomalies, contribute to the rapid expansion of these degraded forests, which could have considerable consequences for local populations. In this project, we will study the mechanisms by which Marantaceae forests may originate and be maintained at different spatial and temporal scales. We will combine observations at the local and regional scales (among which historical data) and parsimonious theoretical models to study the long-term dynamics of Marantaceae forests, the conditions under which stability is expected and the mechanisms by which giant herbs monopolize space and may outcompete trees or restrain their development. The project will be structured in four complementary main work packages (WP): WP0 will be dedicated to synthesize previous studies conducted on Marantaceae forests, of which many were reported as grey literature; WP1 will aim at investigating the main ecological mechanisms underlying the dynamics of Marantaceae forests; WP2 will aim at depicting the contemporary ( 500 yrs) spatio-temporal dynamics of Marantaceae forests based on remote sensing data and historical ecology approaches; and WP3 will consist in devising mathematical models to understand the conditions of a post-disturbance stability of Marantaceae forests and the relative importance of the drivers of this stability. WP3 will thus bridge the scale gap between the local ecological mechanisms (WP1) and the broad scale spatio-temporal dynamics (WP2) of Marantaceae forests. Overall, our project will generate important knowledge on the dynamics of a system that constitutes an important part of the tropical African wet forests and ofglobal concern regarding biodiversity and carbon sequestration in the second largest tropical forest area in the world. It will also contribute to the increased awareness that the dynamics of ecosystems is not systematically reversible and that external forcings may make them shift to alternative stable states. The ultimate goal of the project is to anticipate the potential consequences of global changes on the dynamics of Marantaceae forests and to provide recommendations for forest conservation and management.

Virtual worlds are increasingly used in the entertainment industry to provide users with a unique and extraordinary experience, in which the quality and the extent of the world is central. This quality is usually obtained by resorting massively to artists, which is expensive and has obvious limitations. The goal of the project is to propose high-level techniques to help artists author and create virtual worlds by using a novel data-driven and machine learning approach. This will be done by high-level tools that will support users in their tasks, without any trade-off in the creative pipeline. The project will rely on machine learning methods and will cover a large variety of scene elements (terrains, vegetation, materials). The data will come from various origins (GIS data, from games, simulation, automatic segmentation). The consortium is composed of academics experts in virtual worlds modeling (LIRIS), a video game company (Ubisoft) and experts in vegetation modeling (CIRAD).

SESASA aims at developing a “system of systems (SoS)” for assessing agricultural land-use-and-management-change scenarios and provide adaptive feed-back. SESASA will connect farmer responses to social, economic and climate changes at local scale with planning and policy instruments at national scale. SESASA will explore spatio-temporal opportunities to harmonize conflicts between arable farming, grazing and pastoralism. Our theoretical framework builds on social-ecological systems and considers systemic properties such as emergence effects that arise from a non-predictable amplification of management impacts on the availability of natural resources. Research/ innovation questions the project intends to address: 1. How can social-ecological-systems be operationalized in terms of smart modelling approaches and architectures to enable a highly flexible and low data demanding assessment of the performance of agro-ecological systems? 2. Which adaptation opportunities for arable farming, grazing and pastoralism – using scenarios – are most recommendable in different agro-ecological zones to minder food and water insecurity? 3. How can we transfer such an approach into decision making and consulting? Accounting local land-management practices in large scale simulations is indispensable for understanding complex social-ecological interactions and requires a highly integrative knowledge processing approach based, for instance, on graph-node theories to reflect the complexity of drivers, agents and nature-human interactions of agro-ecosystems. We suggest implementing a multi-disciplinary SoS including the models ECOSERV (France), GISCAME (Germany) and MOWASIA (Burkina Faso) + research on planning and management practices (Burkina Faso, Ghana), environmental assessment (Ghana, Germany) and perceptions of local experts and actors (Burkina Faso, Ghana). This ensemble will be implemented to explore multiple trajectories of agro-ecosystems at nested scales.