Arnaud Lec'hvien's thesis “Soils, plants, pollinators and associated ecological functions in photovoltaic power plants in the south of France: Towards recommendations for the conservation of this biodiversity”.”

Mr Arnaud Lec'hvien, doctoral student at IMBE (teams Functional ecology: from socio-ecological systems to molecules, and Ecology, Ecotoxicology & Chemistry applied to Agroecology and Restoration), and CEFE (Montpellier) will publicly defend his thesis on Wednesday 29 April 2026 at 2pm in the MASSINI amphitheatre at the Saint-Charles Faculty.

In front of a jury made up of :

• Isabelle DAJOZ, Professor, Université Paris cité, Rapporteur
• Estelle FOREY, Professor, University of Rouen-Normandie, Rapporteur
• Catherine PICON-COCHARD, Director of Research, INRAE, Examiner
• Jérémy FROIDEVAUX,Professor, University of Franche-Comté, Examiner
• Raphaël GROS,Professor, Aix Marseille University, Thesis supervisor
• Bertrand SCHATZ,Director of Research, CEFE , Thesis co-supervisor
• Armin BISCHOFF,Professor, Avignon University, Thesis co-supervisor

Summary of work:

Grasslands and meadows perform multiple ecological functions that support ecosystem services essential to humans. The complex biotic interactions between soil organisms and vegetation, between soil organisms and between plants and pollinators contribute to these functions and to the resilience of these ecosystems when they are degraded. These environments are among the most threatened on the planet due to the intensification of agricultural use, climate change and the artificialization of land. Ground-mounted photovoltaic power plants (CPV), although essential to the energy transition, exert a great deal of pressure on grasslands due to their spatial coverage, construction work and the presence of solar panels, which modify microclimatic conditions. They can therefore represent an additional threat or, depending on the context in which they are installed, their technical characteristics and management practices, particularly with regard to grass cover, a potential opportunity for conserving a certain level of biodiversity. The aims of this thesis are to assess the positive, neutral or negative impact of terrestrial CPVs on soil-plant-pollinator interactions in grassland environments and certain ecological functions, to test the effects of different vegetation management practices and to develop ecological restoration methods adapted to this industrial context where the stress generated by the panels is persistent. To achieve these objectives, more than thirty plants in 2 French regions with contrasting ecological, soil and climatic conditions were studied. This selection of CPVs made it possible to deploy 3 complementary experimental designs to study 1) the modulation of the impacts of power plants and solar panels by inter- and intra-regional climatic variations, 2) the combined effects of solar panels and vegetation management and 3) the effectiveness of several ecological restoration techniques and its modulation by solar panels. Regional soil and climatic conditions modulate the effects of solar panels, while grazing reduces the pollination function compared with mowing. Solar panels modify the influence of infra-regional bioclimatic variations on biodiversity. They also limit the effectiveness of ecological restoration, but certain restoration techniques, such as diversified seeding and the addition of pebbles, have shown promising results in increasing plant richness and partially restoring ecological functions. This work provides developers and managers with scientifically proven arguments for taking better account of biodiversity conservation issues.