Alarm as invasive species colonise large swathes of Kajiado land

Authorities within Kajiado county are spending sleepless nights trying to manage an invasive species known as Ipomea that has colonised huge chunks of land.

Ipomea is predominantly within Kajiado central, east, and parts of the south and is now threatening livestock production.

Kajiado CEC for Agriculture Dr Jacktone Achola said in areas where there is ipomea, grass cannot grow.

Achola said the county has an elaborate plan on how to eradicate the plant.

He said Ipomea can only be eradicated through manual uprooting.

“We have allocated money, and we want to uproot through the participation of farmers, as this thing can only be eradicated through uprooting. We are starting next financial year and going onwards to ensure that weed is uprooted,” he said.

Achola said the invasive species have affected livestock production.

County Director for Livestock, Eric Ahenda, said there are a number of invasive species in the county.

“So far, there are only two varieties that have been a menace within the county. One of them is Ipomea, and the other one is mathenge,” he said.

Ahenda said mathenge is spread towards the Kajiado West area.

He said there is no alternative use for Ipomea, adding that the plant has been a great challenge for pastoralists.

“You will find that even within the rainy season, there is no grass for livestock,” he said.

Ahenda said the devolved unit has been collaborating with some of the research institutions and some organisations to come up with ways to control the species.

He said institutions such as Kenya Agriculture and Livestock Research Organisation are trying to find alternative control approaches.

Even though preliminary studies show that the species can be removed by cutting it using a panga and jembe below the ground, it is still labour-intensive.

“We need to think about how to mechanise the control of this plant.”

Ahenda said manual uprooting is yet to be fully embraced by landowners.

He said since the land within the county is still huge, uprooting the weed manually is an uphill task.

Ahenda said the area of land within the county colonised by the plant ranges from 20 to 30 per cent.

He said there is a need for individual good will from the households affected.

For maximum control of the weed, the uprooting has to continue, Ahenda said.

Some communities practicing beekeeping have raised concerns that they feel dizzy or have stomach upset when they eat honey as a result of bees collecting nectar from the species.

He said the concerns need further research.

The Kenya Forestry Research Institute says it is exploring how to manage the weed.

“Kefri is exploring ways of managing the weed by utilisation, including making briquettes,” Kefri Acting CEO Dr Jane Njuguna said.

Kefri has also been battling prosopis, also known as mathenge.

Already, the institute has developed a strategy and an action plan.

“We are now in the process of developing a policy because prosopis is a national issue as it is on everybody’s land. We are doing a policy on how to manage prosopis through utilisation and also embarking on utilising mathenge for commercial production by actually planting it,” Njuguna said.

In 2006, the members of the Ilchamus community moved to court to challenge the government for letting the killer weed keep growing. In tow was a goat that they claimed had lost its teeth to the weed.

Many then laughed about the move by the community. The community, however, had a point.

The representatives dragged the state to court and sought to be compensated for the losses they had incurred since the introduction of the weed.

The court then instructed the formation of a tribunal to investigate the claims by the community. Nothing happened thereafter.

Kefri, through the Environment ministry, has, however, been trying to tame the spread.

In June 2022, the state declared mathenge weed a national disaster because it takes over cropland and pasture and injures animals.

In 2014, a foreign investor tried to set up a multi-million shilling Cummins Cogeneration industry to make use of the weed to generate electrical power, but it closed shop immediately due to logistical hitches.

Kefri says mathenge was introduced in Kenya in the 1970s, among other species from South America, to rehabilitate the arid and semi-arid areas.

This was due to its resilience, fast growth rate, and many uses for fodder, honey production, shade, windbreaks, firewood, and building poles, among other uses.

The tree, however, aggressively invaded areas of indigenous vegetation and manifested a negative impact on rural landscapes as well as on human and livestock health.

Kefri says the largest biomass of mathenge in Kenya is found in Tana River, Turkana, and Baringo counties.

Taita Taveta, Samburu, Isiolo, Mandera, Marsabit, Wajir, Kajiado, Migori counties, and Malindi are other areas where the weed is found.

Today, the weed is spreading like wildfire.

In Baringo South, for instance, the fast-growing vegetation now covers an area of 50 km², with 13 villages affected.

Apart from affecting humans, the hardy weed has rendered livestock toothless, blocked access roads and waterways, ravaged people's land, and caused its roots to crack the walls of houses.

Kefri says the weed has some uses, such as prosopis pods, which are a valuable source of carbohydrates, sugar, and proteins for livestock and, occasionally, the human population during dry seasons.

Another invasive species known as dodder is also giving researchers sleepless nights.

Kefri says dodder is the latest invasive plant species that is a major threat to various ecosystems.

It attacks many plants and can cause heavy economic losses.

Kefri says dodder in Kenya is rapidly spreading and has already been observed in about 12 counties, mostly in the Eastern, Western, and Rift Valley.

It has become a threat not only to trees but also to crop yields, thereby compromising both biodiversity and food security.

Dodder also attacks ornamental and native plants and trees and can reduce the aesthetic value of landscapes.

The Kefri National Forest Health Research Strategy (2018–2023) identified invasive plant species as one of the forest health issues of concern.

The institute says dodder is currently spreading fast in Kenya and, if left unmanaged, is likely to threaten a wide range of trees and crops and may affect food security.

It is said that rigorous awareness creation is critical to imparting knowledge for the successful management of dodder.