World Soil Day on December 5, 2022

African savannas: social-ecological research with the aim to protect soils

Savannas are underestimated and endangered ecosystems. These drylands cover almost half of the land surface and make an important contribution to biodiversity conservation. But due to climate change and unsustainable land use, already up to 20 percent of these ecosystems worldwide are no longer intact. Using Namibia as an example, researchers from the ISOE – Institute for Social-Ecological Research are investigating how sustainable grazing management can prevent the progressive degradation of soils.

| News
Weidetiere in der Savanne, Namibia
Photo: Stefan Liehr (ISOE)

Namibia is the driest country in sub-Saharan Africa and exemplifies the loss of savannah-typical grasslands. Extreme droughts, population growth, urbanisation processes and agricultural use are affecting the soils. Scientists speak of overexploitation when the soils are so severely stressed by agricultural cultivation that they are at risk of  becoming infertile.

Studies undertaken within the “NamTip” research project, in which ISOE is involved, show that the central cause of the so-called degradation of soils is overuse. This has been shown to lead to a deterioration and thinning of the grasslands. Higher-quality perennial grasses necessary for pasture management are replaced by lower-quality annual grasses. New grasses grow less because the reservoir of seeds is also increasingly depleted. If subsequently bare soil remains, a tipping point is reached at which desertification begins. This process of desertification is hardly reversible. Under certain conditions, overexploitation and the reduction of grass vegetation can also lead to an increased bush encroachment which also poses major challenges for farmers.

Tenure in drylands influences productivity of soils

At the Namibian research sites, it is evident that soil degradation has progressed at different rates. Communally owned pasture land is often more affected, in contrast to privately owned land. The reasons are for one discriminatory policies during the colonial era, the consequences of which are still felt today. Here, communal farmers were forced into so-called homelands, where, other than on privately owned farmland overcrowding and overgrazing occurred. The fact that communal farmers were restricted in their ability to move from place to place with their cattle has had a long-term negative impact on pasture quality.

Another complicating factor are more recent legal requirements that have prohibited the village communities from de-bushing. This is necessary, however, as bush encroachment severely disrupts land productivity. Dense shrubs and bushes crowd out other plants, especially grasses, which serve as a source of food for livestock, among others. Scrub encroachment is also a problem for wildlife, as it considerably restricts their natural mobility and leads to declining wildlife populations. In order to prevent large parts of the savannahs with their diverse functions for humans and animals from being irreparably destroyed, concepts for sustainable management of the grazing areas are needed. According to the ISOE scientists, such concepts are crucial, since studies show that climate change is likely to exacerbate this development in the near future due to the increase of CO2 in the atmosphere, higher temperatures and changes in the availability of water. Therefore, it is expected that in Namibia the zones favourable for pasture management will continue to shift northwards and ever increasing savannah areas will lose productivity.

Knowledge transfer as key to successful transformation processes 

ISOE researchers see solutions for the ecosystem of the Namibian savannah primarily in the abandonment of soil-intensive, conventional livestock farming. National policies should be geared towards seasonally adapted grazing management and the prevention of bush encroachment so that more soil-conserving agriculture becomes the standard. The researchers also recommend management strategies involving native wildlife, which are considered more sustainable because they are better adapted to local climatic and ecological conditions. However, this type of use entails many conflicts: farmers, village communities, nature conservation and authorities all view the use of land against the backdrop of very different priorities, economic interests and values. 

In the research projects “NamTip: Understanding and managing desertification tipping points – a Namibian perspective” and “ORYCS – Wildlife management strategies in Namibia”, ISOE is therefore investigating, together with the project partners, how sustainable solutions can be locally communicated. For this to happen, it is crucial that science and researchers establish a dialogue with actors from the field. In an English-language policy brief, ISOE researchers show how results from (ideally transdisciplinary) research can be transferred to practice in order to initiate change processes.

Click here for the ISOE policy brief:

How to reach people through knowledge transfer – Sustainability and conservation research: addressing Namibian land users. Deike U. Lüdtke, Verena Rossow, Nicola Schuldt-Baumgart, Stefan Liehr (2022). ISOE Policy Brief No. 9. Frankfurt am Main: ISOE – Institute for Social-Ecological Research. Download:  

Find out more about the research projects “ORYCS – Wildlife-based management strategies in Namibia” and “NamTip: Understanding and managing desertification tipping points – a Namibian perspective”:  

Scientific contact:

Dr. Stefan Liehr
Tel. +49 69 707 6919-36  

Press contact:

Melanie Neugart
Tel. +49 69 707 6919-51