Quaternary Sciences can provide empirical data prefigurating realistic future ecosystem changes. This is particularly helpful for managers looking at finding a suitable balance between implementing restoration actions and “laissez-faire”, in the light of the climatic projections. Here we present a case study of Historical Ecology applied to a Mediterranean wetland (Bagliettu peatbog, Corsica Island): 1) to reconstruct 3900 years of insect and plant ecological successions and changing habitats, 2) to identify respective and cumulative roles of past disturbances (i.e. geomorphic evolution, climate changes, land use) in the shaping of ecological communities, and 3) to discuss conservation status in the light of the long-term dynamics. This type of peat-bog within the Mediterranean bioclimate is very rare and thus deserves protection. Our findings reveal that this peat-bog has thrived several millennia of evolution with relative resilience to centennial-scale aridity events. However, reduced wetland connection due to a multimillennial-long trend of river incision play a major role in the recent degradation of wetland, unlikely reversible at our human scale. With the added effects of anthropogenic disturbance, which has been identified as increasing in the fossil record, the disappearance of the ecosystem might occur independently of changes in the precipitation regime even if reclamation actions are initiated. Another peat-bog located in the same river valley (Valdu), is probably a more valuable target for conservation. Indeed, a closer position to the aquifer makes this wetland comparable to a young stage of the geomorphic evolution of Bagliettu, and thus more suitable to achieve goals of long-term conservation.