Land Cover Change Monitoring System for Sub-Saharan African Protected Areas
Szantoi, Zoltan; Brink, Andreas; Simonetti, Dario
Joint Research Centre, ITALY
Assessing the state of protected areas and their surroundings are increasingly important as natural resources, the biodiversity and the landscape are under relentless and ever increasing pressure. The European Union pledged significant contribution toward conservation and the management of protected areas in the African-Caribbean-Pacific (ACP) regions, with special emphasis on Sub-Saharan Africa. Assessment of land use/cover change, particularly deforestation and devegetation, are essential for managing protected areas and their surroundings. Furthermore, the monitoring system is able to recognize hotspots of changes, supply information for longer term decisions, assess the current and future values, status and threats of these areas. The European Commissionís Joint Research Centre (JRC) (Ispra, Italy) developed a semi-automatic approach which detects land use/cover change for the period of 20 years, starting from the 1990ís. Additionally, the system is capable to handle new, incoming satellite imagery, with special interest on Landsat 8 and Sentinel 2 datasets. The system consists the necessary pre-processing steps, such as radiometric calibration and normalization, cloud and cloud shadow masking, topographic correction using Shuttle Radar Topographic Missionís digital elevation data (90m), de-hazing and mosaicing. The Tropical Ecosystem Environment Observation by Satellites (TREES) project of the JRC is based on a systematic sampling of satellite imagery and reports estimates on land cover change over the ACP regions since 1990. The latest results of the TREES (2010) project showed that many protected areas and their vicinity lost tree cover, their natural landscape became more fragmented. Accordingly, our main objective was to detect, map and quantify the occurring losses/gains in the investigated period by using Landsat and/or Disaster Monitoring Constellation (UK-DMC 2) imagery and object based classification. The following land cover classes were assessed and differentiated to map the protected areas and their 20 km buffer zones: (1) tree cover -over 70%-, (2) tree mosaic -between 30 and 70%-, (3) other wooded land, (4) other land - non woody land cover such as herbaceous, pasture and crop-, (5) bare or artificial (6) water and (7) cloud and shadow. In this presentation, the status of the monitoring system will be presented with land cover change estimation results for the investigated protected areas. The detected land cover dynamics are presented as change detection maps for selected parks with different levels of change, and quantitative results reveal specific information on tree loss, vegetation degradation, fragmentation and agricultural expansion or in some cases reforestation throughout the studied years. The detected changes in these areas are then discussed within the framework of tropical deforestation, habitat loss, trends in these protected areas, agricultural intensification and urban development.