Résumé
The South-western Indian Ocean is characterized by various heterogeneous insular territories. Many of these islands are biodiversity hotspots and in order to preserve this heritage, some of them are protected. In La Reunion, the Parc National (created in 2007 and on the UNESCO world heritage list since 2010), covers 40 % of the territory while since 2006, Europa island (Shattered Islands) is a national natural reserve where some areas are integrally protected. Forest fires are a major threat to these areas of preserved biodiversity. Last main fires in La Reunion occurred in 2010, 2011 and 2013, and in june 2013 on Europa island.In 2013, the monitoring and mapping of the fires of Etang-Saint-Paul (July, La Reunion) and Europa (June) were carried out by the SEAS-OI (Survey of Environment Assisted by Satellites in the Indian Ocean), in collaboration with the ONF (Office National des Forêts) of La Reunion and the SDIS (Service Départemental d’Incendie et de Secours), using high resolution SPOT 5 imagery. These maps allowed the estimation of the fire extent, to about 4 and 70 hectares for Europa and Etang-Saint-Paul respectively, and to support field intervention during the crisis.In both cases, the monitoring of post-fire recovery of the affected areas was realized using PLEIADES images acquired by the SEAS-OI station in the frame of the CNES RTU. This part of the study is still ongoing and aim at taking advantage of the very high spatial resolution offered by PLEIADES products in order to quantify precisely the extent of the burned surface during both fires, and provide first insights on the post-fire evolution in terms of plant recolonization. This is an important issue in these protected areas where the ecosystems are threatened by the post-fire settlement of invasive species.This study was part of the operational mission of the SEAS-OI station, gathering local actors in the management of forest fire crisis in the south-western Indian Ocean. In particular, we demonstrate here the interest of the satellite approach in the management of natural disasters on remote territories like Europa island, and in protected areas where a rapid response is needed. Thanks to the combination of optical SPOT 5 and PLEAIDES high resolution products, SEAS-OI was able to provide operational products for the management of these fires. These applications led to a partnership between SEAS-OI, the ONF and the SDIS, whose objective is to use satellite images to monitor the protected territories of the Iles Eparses.