Résumé
Mangroves are a vital natural heritage and our ability to ensure their preservation is a key issue in the fight against global warming, the preservation of biodiversity and the livelihoods of the growing human population concentrated along the coasts. Over the last half century, however, mangroves have suffered an alarming loss of global cover. In order to improve the understanding of mangrove dynamics and functioning, up-to-date and recurring mangrove mapping and monitoring tools are essential. MangMap is a new online monitoring platform dedicated to the production and dissemination of specific products and services useful for mangrove mapping and monitoring at local scales. MangMap relies on generic processing services using Sentinel-2 satellite image time series, updated every 5 days from 2018. MangMap provides a complementary approach to existing tools. The platform provides an interactive dashboard dedicated to the production of enduser driven products useful for mangrove monitoring at local scales. Each image transformed into reflectance levels (2A) is available for download along with 11 automatically processed spectral indexes characterising the mangrove environments. An automated vector contour of mangrove spatial distribution is calculatedquarterly. Temporal composites of all indexes are processed monthly, quarterly, semi-annually and annually. Endusers can browse and import all data sets with simple tools. They can perform specific on-demand analyses within their own areas of interest, uploaded to the platform or drawn on the products on the screen, for a chosen period of time: indicator of mangrove spatial evolution; calculation of index differences; statistics on index evolutions. In its demo mode, the first version of the platform focuses on 5 pilot sites, which will be complemented by 11 other study sites spread over the regions of South America, Africa, Asia and Oceania. Further upgrades, based on feedback from early users, will aim to improve the enduser experience and provide new Earth Observation products and services based on very high spatial resolution imagery and radar data time series. Overall, MangMap, with its interactive website and technical platform, is designed to support studies and institutional diagnosis with simple tools, services and products to help map mangroves with up-to-date pre-processed spaceborne data. Ultimately, MangMap’s aims is to contribute to policy-making for the preservation and restoration of coastal ecosystems.