Comoros archipelago is among the 20 island states within biodiversity hot spots, in terms of global conservation priorities. Grande Comore is the largest and well-preserved island in the Comoros archipelago. Taking into account nature and the various natural and anthropogenic pressures, it is im-portant to promote a management plan that would guide future conservation issues for the island's ¿ora and habitats. Nevertheless, considering the fact that little data exists for the Comoros, it is necessary to develop a methodology that is both rapid and repeatable, in order to delimit the ZNIEFF (Natural Zones of Ecological, Faunistic and Floristic Interest) in Grande Comore Island. Given the urgent need to de¿ne a conservation plan in the Comoros, we have focused this study on the remnant forests of La Grille, on the northern side of Grande Comore Island, a choice motivated by the accessibility of this site and the size of its massif (300 km2). We have delineated the board units of vegetation by ortho-photography using QGIS software and existing data. This experimentation will be followed by a ¿eld survey using a ZNIEFF-type inventory, as well as a veri¿cation of the delimited areas based on the data recorded on the study site. It will then provide an approach on the state of conservation of remnant forests, the di¿erent types of pressures within natural and semi-natural habitats and the extent of existing threats, including invasion by exotic species. The approach de¿nes areas of ecological interest and provides a management framework for prioritizing habitat conservation choices. It will thus serve as a decision-making support for future biodiversity conservation issues in the Comoros.