Invasive species in Namibia – a BSc research report

Dense riparian vegetation on the banks of the Orange River consisting of invasive Prosopis as well as native species

I am Daniel Oberhauser from Germany and I traveled to Namibia where I investigated how invasive plants can be removed from a national park by bringing local communities on board. With this research I completed the BSc Forest Sciences at the Technische Universität Dresden in August 2017.

The Project

The Ai-Ais Richtersveld Transfrontier Park is situated along the Orange River which demarcates the border between Namibia and South Africa. Both countries manage the protected area jointly. The area is hyper arid and hence most of the vegetation in the park is found on the banks of the Orange River. Non-native shrubs and trees of the genus Prosopis invade the park along the river. While the South African park management authorities have already established a community-based alien-plant removal scheme, the Namibian authorities are yet to undertake such measures. To support this, my dissertation served as a feasibility study for the Namibian park management and therefore looked into Prosopis distribution, biomass estimation, and removal strategies.

Map of the Ai-Ais Richtersveld Transfrontier Park

 

Method

To gain an insight into Prosopis distribution within the park, I mapped Prosopis plants in 14 sample areas on the banks of the river making use of GPS technology and satellite imagery. To estimate the biomass of the plants, I took note of the plants’ basal diameters which allows to infer to woody biomass based on models available in literature. To understand and evaluate different strategies of Prosopis removal, I held interviews with a number of experts and local stakeholders. In this context I also analyzed marketing opportunities for products that could be derived from harvesting Prosopis. By doing so, the park management authorities hope to partly compensate for the costs of the operation.

One of the sampled areas. Plants of the genus Prosopis are marked in light green

 

Results

I found that the removal and harvesting of Prosopis in the Park is most feasible in a set-up where members from the local communities remove the plants in a small-scale, low-technology but labor-intensive approach. The harvested wood should be processed to firewood and marketed locally. The business proposal requires modest investment and is likely to have little environmental impact. Certain components of such a project must be subsidized by the park management authorities – e.g. the required tools like chainsaws, while the returns from marketing the wood should cover the wages of the employed community workers.

Investigating value chains for Prosopis products by interviewing local timber producers.

 

Outlook

The pilot phase of the project will be implemented soon. It will receive a kick-off funding from the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ). This will allow to make the initially required investments. For me personally, the dissertation was a great opportunity as I could contribute to the potential solution of a real-world problem. This means that I had the chance to engage with local stakeholders but also with professionals involved in the issue. Such an experience is very enriching as one can gain an understanding of how academic theory can be matched with practical challenges.

 

The study was crafted based on interactions with a lot of different people. I would like to take the opportunity to thank Richard Fryer and his team (Namibian Ministry of Environment and Tourism, MET), Dr. Ben Strohbach (Namibia University of Science and Technology, NUST), Martin Leineweber and Johannes Laufs (Deutsche Gesellschaft für Internationale Zusammenarbeit, GIZ), as well as Dr. Eckard Auch, Prof. Jürgen Pretzsch and Prof. Gerald Kapp (Chair of Tropical Forestry, TU Dresden) for their support.

 

By Daniel Oberhauser

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