East of Madagascar lies the Mascarene archipelago, composed of three islands: Rodrigues, Mauritius and La Réunion. Because of topography, the lack of natural harbours and its remote position in the South West Indian Ocean, these islands remained for millennia loosely connected to the Afro-Asian world system that shaped this basin. Before human colonization, 88 per 100 of the islands were covered by forests, home of many endemic and iconic species (like the solitaire, parrots and giant turtles, etc.). 90 per 100 of the flora was considered endemic from the South-West Indian Ocean. Taken over by the French Companie de l’Orient in 1638, La Réunion and Mauritius progressively became a plantation economy specialized in the production of tropical commodities – coffee, spices, sugar, essential oils – with slaves and indentured workers. Due to the absence of indigenous population, these islands constitute one of the few and first societies literally shaped by an economic imperative. This paper analyses the institutionalization and expansion of a specific variant of the island plantation system, from a diversified coffee and spice planning system to a sugar monopoly. It then depicts how the ecological feedbacks and the island unique characteristics, progressively compromised the prosperity and sustainability of the plantations and the creole ecologies, plunging the island into structural land use pressure, food vulnerability and health crisis. A last part explores the forced ecological transition during the World War Two in La Réunion, because of the collapse of sugar plantation to feed people. To this end, we focus on primary and secondary sources from national and departmental archives and libraries, as well as in-depth research into the historiography with an environmental perspective.