By Phoebe Weston and Patrick Greenfield
In the grand saga of environmental challenges, few villains are as notorious as the invasive Mathenge (Prosopis juliflora) plant. This green menace has been spreading its tendrils far and wide, wreaking havoc on local ecosystems in semi-arid areas of Kenya.
Despite the menace of the shrub, a project led by VSF Suisse along with the University of Nairobi and the county governments of Samburu and Isiolo is turning a thorn in the side of the locals into a boon for their livestock and the environment, through innovative ways to control its spread while simultaneously reaping its rewards.
One of the techniques they have adopted is turning mathenge pods into livestock feed by grinding and mixing the seeds with straw, bean husks and acacia pods: “That allows us to produce fodder, which we then store for the entire dry season,” says Martina Lenanyangerra, a community leader involved in the project.
“The goal is to formulate a feed that is high in nutrients and easily digestible for livestock. When mixed, the sugar content in the pods decreases, making it a safe feed while also helping to contain the plant’s spread,” says Edward Musya, a vet and master’s student studying animal nutrition at the University of Nairobi.
The project has also introduced briquette production as a fuel source by turning mathenge wood into charcoal. In Samburu, where more than 95% of people rely on firewood or charcoal for cooking, this has helped ease pressure on native trees while also offering a new source of income.
But to rein in the plant’s spread, larger interventions will probably be required: “There’s no way we are going to eliminate the plant. That is why we need to control it,” says Ramadhan Golicha, an environmental officer with the Isiolo county government.
Introduced from South America in 1970s, mathenge was intended to halt desertification. FAO and the Kenyan government actively encouraged its planting. It was seen as a remedy for creeping desertification, providing tree cover and preventing soil erosion in drylands, as well as a source of fuel and animal fodder. As the shrub spread, it quickly became a nightmare.
“The spread is so fast that it has caused entire communities to be displaced, schools to close, and even disrupted river flows, as the plant blocks watercourses, contributing to flooding and displacement,” says Davis Ikiror, Kenya-Somalia country director for Vétérinaires Sans Frontières (VSF) Suisse.
The Kenya Forestry Research Institute (Kefri) estimates Mathenge has encroached on 2 million hectares and is spreading at a rate of up to 15% a year.
Mathenge’s deep root system, reported to go as down as far as 35 metres below ground, siphons off precious water that other species require. Its branches grow so thickly and its roots are so deep that an incursion can even alter the course of rivers. The slowed water flow and dark canopies create ideal breeding grounds for mosquitoes – which worsen the spread of malaria, Rift Valley fever, and kala-azar.
Courtesy of Guardian News & Media Ltd. Original article available at: https://www.theguardian.com/environment/2025/may/22/kenya-mathenge-desertification-invasive-plants-neltuma-prosopis-juliflora-samburu-pastoralists-aoe
