Impact of the platyhelminthe Obama nungara invasion on earthworm communities in France – PLATWORM

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.