The aim of the MARIS project is to provide a new framework for the sustainable management of risks of biological invasion. Biological invasions and their effects on ecosystem biodiversity and functioning are one of the main causes of global change. The management of invasive species depends on both the knowledge of the ecological characteristics of the target species and of the sociological contexts that control its installation, persistence, the perception and potential spread through dispersal. The MARIS project will use Ulex europaeus (L.), a ‘world invasive species’ outside its native European range, as model species. We will study it in a wide range of ecological and social conditions both in native (French Brittany and Landes of Gascogne) and invaded areas (French Reunion Island, New Zealand and the Spanish Canary Islands). The ecological part of the project will focus on three specific stagers for the control of the population dynamics: recruitment, persistence and dispersal. The climate and soil conditions which favour successful recruitment of seedlings and persistence (seed bank and resprouting) of the species will be assessed in meta-analysis, experiments (using phytotron and common garden) and field surveys. This part of the project will also address the dispersal distance enabled by different vectors (vehicles, sheep and water). The sociological part will focus on analyses of human perceptions and uses of Ulex europaeus. A mechanistic species distribution model will be coupled with existing models to simulate population dynamics at the stand scale to account for local processes at regional scale. To achieve the right balance, the uncertainty of model outputs and the complexity of the local scale model will be weighed against the gain in accuracy provided by the final hybrid model. Field surveys and experimental results as well as information collected on social uses and perception of the species will be included in the model. The global risk analysis framework will be used to combine all the results of the project. Results of the ecological experiments and of the field studies and expert knowledge will be used to define biological thresholds. Sociological field surveys will make it possible to account for the perceptions of the different actors (managers, users) in creating scales for the assessment of risk as well as for drawing up risk management plans. Economic data on the cost of the Ulex europaeus eradication programme in the literature will be used to propose a pragmatic sustainable management to control its expansion.

Modelling fluvial morphodynamics in the face of environmental changes requires the consideration of feedbacks between hydrogeomorphological processes and riparian vegetation dynamics. Hydrogeomorphological processes control vegetation dispersal, recruitment, establishment and succession. In turn, vegetation strongly impacts water flow and sediment transport. Only a restricted set of riparian plant traits are needed to describe the response of vegetation to, and its effect on, river morphodynamics. However, biogeomorphological feedbacks are still poorly considered in fluvial morphodynamics numerical modelling. The objective of the project NUMRIP is to develop a numerical model of river biogeomorphological dynamics integrating feedbacks between hydrogeomorphological processes and a set of key riparian vegetation functional traits. We will develop an innovative scientific tool for fluvial hydrosystems management and restoration.