CSIR remote sensing specialists studied satellite imagery of South Africa’s savanna system over the period 2001 to 2018 which showed that as the climate became drier, farms were abandoned, which in turn led  to an increase in tree cover.

“The grass-tree co-existence of the Savanna is crucial to the provision of important ecosystem services, including grazing and browsing resources to livestock and wildlife; and the provision of food and medicinal plants to the human community,” says CSIR remote sensing specialist, Dr Moses Cho.

The Kruger National Park is located in the Savanna system and the variability of grass and tree cover is controlled by a number of environmental and human- induced factors. For example, increasing levels of atmospheric carbon dioxide released from industries and other human activities favour tree growth in the savanna, causing bush encroachment.

Cho warns that this could lead to the expansion of tree cover at the expense of grassy areas, adding that other activities such as deforestation, overgrazing and farm abandonment are equally changing the dynamics of tree and grass cover in the region.

While increasing bush density in the savanna reduces land accessibility by wildlife and livestock, the researchers acknowledge that the increase in tree cover has the potential to increase the landscape’s resilience to the impacts of droughts. 

This research was published in the International Journal of Applied Earth Observation Geoinformation.