Decision support tool for gorilla conservation in Central Africa
Mountain gorillas live in a montane forest habitat found in in the Democratic Republic of the Congo (DRC), Rwanda and Uganda. The region is renowned for the diversity of its natural habitats and their incredibly varied wildlife. It includes three World Heritage sites: Virunga National Park and Kahuzi-Biega National Park in the DRC, and Bwindi Impenetrable National Park in Uganda.
The mountain gorillas’ habitat is in a vast area of mountainous terrain that is not easily accessible, which includes some of Africa’s highest peaks, reaching altitudes of over 5000 m. Moreover, the region is recovering from a long conflict which has left painful rifts in its social, economic and ecological fabric. In such conditions, only space technologies offer solutions to the inherent problems faced by local authorities in their efforts to undertake overall environmental assessments; using remote sensing is then both necessary and challenging.
Decision support tools derived from satellite imagerie
Through this project, accurate basic cartographic products covering the entire habitat were produced for the first time, derived from satellite imagery. These include elevation models, vegetation and land-use change maps, as well as 1:200 000 and 1:50 000 scale cartography. A comparison of satellite images of the sites taken between 1990 and 2003 provided an accurate picture of the impacts of the long period of political unrest on the environment. The conflicts lead to the arrival of refugees and the development of new human settlements, deforestation, and, in some cases, forest regeneration.
Thanks to UNESCO’s space partners, Central Africa now counts with accurate cartography for the management of their heritage sites. The cartographic products, which are compatible with geo-positioning systems, allow national conservation authorities to track all flora and fauna, including the gorillas, and to monitor any changes or degradation of their habitat. A series of training workshops were also organized to enhance local conservation and management capacities.
Now national conservation agencies and the non-governmental organizations assisting them in and near the parks can identify also park boundaries, map their observations with respect to flora and fauna surveys, visualize movements of the fauna, and plan gorilla-associated eco-tourism.
Extracting additional features to improve cartography
The Canadian Space Agency (CSA), a partner of UNESCO’s ‘Open Initiative’, contributed to the project with associated coverage of RADARSAT images for UNESCO’s activities in Central Africa.
RADARSAT-1 is a sophisticated Earth Observation (EO) System designed to monitor environmental change and our planet’s natural resources. Day or night, in all weather and through cloud cover, smoke and haze, RADARSAT can acquire images of the Earth using its powerful Synthetic Aperture Radar (SAR).
The results further confirm that optical satellite images are not sufficient when working in tropical areas. The added value of radar allows for the extraction of additional features: river networks, park borders, deforested areas, etc. In some cases, radars can even detect human induced vegetation.