Recreational boating and environment. Practices, behaviors and environmental impacts of recreational boating on islands. Glenan archipelago case study. ; Plaisance et environnement. Pratiques, représentations et impacts de la fréquentation nautique de loisir dans les espaces insulaires. Le cas de l'archipel de Glénan (France).

Recreational boating in France concerns 4 millions persons. 450 000 boats are effectively used and the nautical branch is one of the most important leisure activity in terms of economic weight. The development of this activity associated with a growing social demand for nautical leisures raise the question of its management: development planning, uses management and conservation of environment and biodiversity. Through a study of nautical touristic frequentation in french coastal islands, this research proposes a typology of insular areas integrating geographical characteristics and diversity of nautical activities. The problematic of the management of frequentation in marine and terrestrial areas and the conservation of sensitive coastline is addressed through the case study of Glenan archipelago (south coast of Britany), a famous yachting spot in France. The types of boaters frequentation result from social (practices) but also technical (boat characteristics) aspects, and are analysed in their spatial and temporal distribution. A detailed study of nautical frequentation enabled to identify real and potential environmental impacts of boating on Glenan archipelago. Several pratices are susceptible of perturbating ecological equilibria of the archipelago. We chose to study the impact of mooring and anchoring on zostera marina seagrass bed, following a multidisciplinary approach in geography (human geography, remote sensing and geographical information system) and biology (observational, experimental and in situ approach). Our results show the large variability of the anthropic impacts depending on the area characterics, but overall a larger resilience of this seagrass bed in contrast with the mediterranean Posidonia oceanica. This thesis work contributes to the knowledge of still poorly known activities as compared with their development, to the understanding of nature and society interactions in coastal areas, in the perspective of integrated coastal zone management. ; La plaisance et les loisirs nautiques en ...