Ecopotential Storyline: Savanna dynamics at Kruger National Park

The Kruger National Park (KNP) and surrounding areas is a semi-arid ecosystem supporting high levels of biodiversity and also benefits from ecotourism that contribute substantially to the South African economy. As the largest biomes in sub-Saharan Africa, these ecosystems host a large proportion of the African population, generally the poorest communities, who rely extensively for their daily sustenance or livelihoods on ecosystem services, e.g. fuel wood, timber, grazing resources and edible fruits.

The woody component or tree cover plays a key role in ecosystem functioning, impacting on the fire danger, rates of transpiration and biomass production, nutrient cycling, soil erosion, and water distribution, and more widely on food and energy security. Bush encroachment impacts negatively on available grass resource for herbivores including wildlife and livestock. On the other hand, about 90% of rural community relies on fuel wood as their main source of energy and livestock production as their mainstay for livelihood.

Grazing and browsing resources supporting wild fauna and livestock production are the main provisioning ecosystem services. These provisioning services are crucial to sustaining ecotourism, which is the main cultural ecosystem service, and rural livelihoods in the region. However, grazing and browsing resources are threatened by phenomena such as bush encroachment, overgrazing, elephant impacts and poaching of large mammals.

The main research question is to investigate the dynamics of the savanna ecosystems and their impact on key ecosystem services in KNP. The proposed approach relies on various remote sensing technologies depending on vegetation type. For the grass layer for grazing animals, herbaceous biomass (available grazing resources) and quality (leaf nitrogen) are assessed using high spatial resolution images such as Sentinel – 2 and WorldView-3, with strategically placed red-edge band for assessing vegetation health. For the tree layer, woody biomass and tree cover will be assessed using a combination of state of art Synthetic Aperture Radar (SAR) and LiDAR technology.  The estimated vegetation parameters will be further used for modelling ecosystem dynamics and carbon and water fluxes through the soil-vegetation-atmosphere system in different geological frameworks, as well as to assess, through modelling, the response of savanna ecosystems to changes in climate and/or in the fire and grazing regimes.