Impacts of land use transformation on CO2 storage in savannahs

There are conflicting notions of how rural Africa is to develop. On the one hand, governments and nature conservationists want to protect the savannah ecosystems in order to preserve the habitats and migration zones of animals such as elephants and lions. On the other, the local population’s food supply is based on crop farming, so that, also because of climate change, it will only be possible to ensure their food supply by intensifying agricultural land use. 

Since arid zones represent the largest terrestrial carbon sinks, such prospects for the future will also have a considerable impact on global carbon sequestration. “Until recently, however, the storage potential of savannahs was not sufficiently researched, and its carbon dynamics regarding interfering factors such as damage caused by elephants gnawing, logging and livestock breeding were only partly understood,” says Dr Liana Kindermann of the University of Potsdam, who is lead author of the study, which was published in the specialist journal Global Change Biology in April 2025.

Kindermann and her team developed a method to estimate carbon sequestration in such disturbed ecosystems enabling them to quantify carbon in trees, shrubs and their roots as well as organic carbon in the soil. “Taking a few representative locations, we look at how decisions on land use taken today can change the entire landscape in the future. We process this data with high-performance statistical models in order to assess the effects of future land use transformation on surface carbon and carbon sequestration in the ecosystem as a whole,” Kindermann explains. “Our results show that vulnerability to disturbances differs considerably depending on the respective land use scenario,” she stresses.

Trade-offs between land-use objectives and carbon storage goals must be considered

As wild animal density increases, surface carbon sequestration in shrubs and trees diminishes by an average 14 to 55 per cent, and with intensive agriculture, as much as 73 to 94 per cent of carbon is lost in comparison to locations with a low level of disturbances. In contrast, the soil’s organic carbon content may even increase in the event of major disturbances, especially when herbivores like elephants eat surface vegetation and thus spread carbon in the ground. However, this process is limited and can only work if vegetation is stably retained and not destroyed by excessive wild animal density. Soil carbon content is important in agricultural use of the land. This is reflected by the fact that so far, agricultural land has been created predominantly where soils already contain more carbon. 

Decisions on how the land surface – also with regard to biodiversity conservation – is to be used in the future change the savannah’s functions and ecosystem services. “Occasional and localised disturbances of vegetation by large herbivores and pastoralism have a positive effect on carbon sequestration in the savannah if the vegetation also has the opportunity to recover. Extreme interventions like large-scale clear-cutting as well as consistently excessive wild animal density damage the carbon cycle, causing disadvantages for environmental protection and people’s livelihoods. Sustainable strategies for tomorrow’s land use therefore require transparent assessment of such conflicts in aims and sustainable compromise solutions for all,” Kindermann states, summing up the implications of the findings.

(University of Potsdam/wi)

Reference:
Kindermann, L., Sandhage-Hofmann, A., Amelung, W., Börner, J., Dobler, M., Fabiano, E. C., Meyer, M., Linstädter, A., 2025, Natural and human disturbances have non-linear effects on whole-ecosystem carbon storage in an African savanna, Global Change Biology, Volume 31, issue 4; 15th April 2025
https://doi.org/10.1111/gcb.70163