The Kerkennah archipelago is composed of low islands where the lithology is fragile. The coasts are also threatened by the rise in sea level (+17cm between 1946 and 2006) due to the subsidence in the north of the Gabes gulf and the increase of sea water temperatures. Tunisian society has changed in the last 50 years with, inter alia, a rise in the standard of living and the possibility of building houses and villas along the coast. In the Kerkennah archipelago, this has led to recent urbanization along the coastline. In this very fine-scaled example, we aim to assess the vulnerability linked with this socio-ecosystem that combines human and natural factors. We also take into account the spatial (and temporal) dynamic associated with the longshore drift. Our results show that (i) the spatial dynamic is a critical factor that needs consideration, and (ii) the assessment process requires excellent knowledge of the area being studied. Finally, we conclude that in the context of the development of systemic studies, both the territories themselves and the relations between the different areas that compose a territory must be studied as factors of vulnerability.