BARINGO, KENYA – Farms and grazing fields in Baringo county have been invaded by the poisonous Mathenge weed (Prosopis juliflora).
Rapidly spreading weeds have reached the shores of Lake Bogoria and some river segments, obstructing water flow for irrigation projects.
Environmental researchers have declared that the tree species threaten the country’s food security.
This publication understands that Mathenge, a South American species, was introduced to the region in the 1970s to curb desertification.
“One of the things that the Mathenge tree has done is that it has overgrown and reduced the wild wings that used to occur within this area,” said Susan Jepkemoi, the Chief Executive Officer at the Baringo County Conservation Association (BCCA).
According to Jepkemoi, Mathenge has also increased the vegetation cover, and there is less erosion, especially from wind and some surface runoff,
“But on the other hand, Mathenge is a tree that thrives very fast, especially during the rainy season, and it is very resistant during droughts. So, with its strength as a species, it has outcompeted most of the native plants, both trees and grasses,” Jepkemoi.
The environmentalist observed that this means that the locals have lost grasses, and being pastoralists, it is very painful to them since they depend on the grasses for pasture, thus affecting their livelihoods.
Also, cattle don’t like feeding on the leaves; they prefer other trees or shrubs.
In June 2022, Keriako Tobiko, then the Environment Cabinet Secretary, revealed that Mathenge had negatively impacted 20 counties, occupying approximately two million hectares of land while spreading at a rate of 15%.
This was meant to revive the Arid and Semi-Arid Areas (ASALs) due to the tree’s durability, rapid growth rate, and multiple uses such as fodder, honey production, shade, windbreak, firewood, and building poles.
According to Boniface Kiteme, Director of the Nanyuki, Laikipia County-based Center for the Training and Integrated Research in Arid and Semi-Arid Lands Development (CETRAD), the country’s ability to control invasive weeds will determine how the rangelands develop in the future.
“In a landscape like Laikipia, so as you go down to the lowlands and spread further to Baringo and Garissa, Mathenge is a serious threat to the future of the rangelands,” warned Kiteme.
A mature Mathenge tree can use 20 to 30 litres of water a day, according to Kiteme.
“So, get a piece of land, one acre, count the number of mature trees, multiply that by 20 litres, and know how much water is lost in that one acre through Mathenge,” Kiteme continued.
According to Kiteme, no other vegetation can grow once the Mathenge cover surpasses 40%. This directly impacts the rangelands’ grazing and water supply for animals.
Here, Kiteme identified three significant areas where CETRAD has conducted research, with the primary findings recently published.
“We have done mapping at two levels; suitability of invasion and the current situation of invasion. A good part of the Northeastern region of Kenya, stretching from Garissa to Turkana,, has a good part of its suitable invasion, and many parts are invaded by Mathenge,” Kiteme stated.
Johanna Karatu, opinion leader, Endorois community member, and trustee member of Kiborgoch Community and Wildlife Wetland Conservancy, said they had gotten a donor willing to help them eliminate the tree species.
“Now, this tree poses a threat to our way of life. It has started to pose a risk to our cattle; for example, goats that consume it lose weight and get weak teeth. If there is one advantage to them, it is that they burn charcoal well. We chop the trees to make charcoal, but they still sprout and grow again,” Karatu clarified, noting several negative and beneficial repercussions of mass extinctions.
Meanwhile, Jepkemoi revealed that the other important part of this plant is the pods.
“Research shows it has good protein for livestock and even wildlife. But the problem is that when they feed on them, from their waste, the Mathenge thrives very fast in those areas, thus colonising the entire-colonising,” she explained.
Jepkemoi restated that Mathenge is a species of tree that requires management, particularly in areas where it is unnecessary.
“If cutting is used to manage it, something else needs to be restored within the area right away, or else we’ll have a situation where degradation occurs again,” she continued.
According to Jepkemoi, using plants sustainably and removing them from vulnerable locations is critical.
“For instance, because of the Kiborgoch wetland, if Prosopis juliflora colonises the region and colonises a lot of water, we will lose the wetland entirely and other trees and grass,” she added.
According to Tobiko, the tree had aggressively invaded areas of native vegetation, posing a threat to the health of cattle and people living in rural areas.
Stanley Kiptis, a former governor of Baringo, said that Mathenge has always had terrible effects on the local populace and fauna.
In addition, Kiptis urged the national government to offer a long-term resolution to the issue.
The Kenyan government’s efforts to develop a National Strategy and Action Plan report, mainly aimed at eradicating Mathenge via the ‘management by utilisation method,’ appear unsuccessful, as the report has yet to be implemented by the relevant authorities.
