Drylands cover approximately 40% of the land surface of the Earth and support roughly one-third of the global human population. The savannah biome in particular covers 50% of the African continent and 20% of the global land surface, while also representing around a third of terrestrial net primary production, and comprising a critical regulating component of the land carbon sink. Over the last decades, savannahs have been under pressure from human activities, exacerbated by climate change, with dramatic shifts in vegetation distribution and, consequently, alterations of their function, threatening the ecosystem services provided to some of the continent’s most vulnerable populations. Therefore, monitoring the process and evolution of land degradation in these ecosystems is considered of great importance for the scientific community, regional and national governments, as well as international organizations and institutions, such as the United Nations Convention to Combat Decertification (UNCCD).
Land degradation in savannahs has often been associated with the encroachment or densification of its woody component at the expense of grasses. Savannahs in Africa are vital ecosystems that support millions of pastoralists whose livelihoods are increasingly threatened by woody encroachment. Monitoring the woody component of savannah land cover is, therefore, needed to enhance the understanding of broad-scale changes in savannahs and their relationship with ecosystem degradation. Over large scales, this can only be achieved in a cost-effective manner using Earth Observation (EO) technologies. The development of the Horizon 2020 SAV-EO project employed novel remote sensing methodologies based on freely-available EO optical and radar satellite data for the mapping and monitoring of fractional woody cover over South African savannah regions.
The specific objectives & final contributions of the SAV-EO project were:
1. Development of a pipeline that monitors bush encroachment over South African (SA) savannah environments through accurately mapping of fractional woody vegetation cover & its progress across the years.
2. Development of a pipeline that monitors bush encroachment at the species level over SA savannah environments through accurately mapping of fractional woody vegetation cover at the species level.
3. Development of a savannah degradation monitoring web-tool assessing vegetation maps & contributors of degradation processes in SA savannah drylands.
4. Development of an intercommunication basis between EO scientist & local stakeholders & population in SA savannah regions in order to develop & update the derived monitoring tools targeted to their current needs.
