Alien plants turn East Africa into ‘green desert’
The Opuntia stricta cactus, known as the erect prickly pear, is native to the Americas. It was introduced to East Africa decades ago as an ornamental plant, but has since spread throughout the continent with a devastating effect on peoples lives, reducing land productivity and harming livestockCABI
Pastoralists in Laikipia county in central Kenya depend on their biodiverse habitat for their livelihood. But the land is being overrun by prickly pears, threatening the way of life of Maasai herdspeople and their familiesCABI
The cactuses spines can blind or otherwise seriously injure livestock foraging near the plants. When goats, sheep and other animals try to eat the plants fruit, the spines can cause painful abscesses, which inhibit feedingCABI
With the Kenyan governments permission, not-for-profit CABI (Centre for Agriculture and Biosciences International) introduced this type of cochineal to Laikipia county to control the cactus. The female produces a protective thick white web and sits underneath it. It kills Opuntia by eating its flowers and fruitCABI
Woody plants such as Prosopis juliflora, which here surrounds a home, are aggressive invaders originally from Mexico, South America and the Caribbean. Large programmes have been rolled out to mitigate their harm, but in East Africa, where villages are more vulnerable to invading species, Prosopis is still difficult to controlCABI
A farmer holding a Prosopis branch explains how difficult it is to live with this invasive weed, whose uncontrollable proliferation can displace entire communitiesCABI
George Achilla is a farmer in the Kenyan village of Kikopey. He grows crops to feed his family and make a small profit. But his land has recently been overrun with Parthenium. He spends a large part of his day removing the shrub from his farm to make space for vegetables and livestockCABI
In Kenya, Parthenium has taken over large areas of land, displacing existing plants and animals, and creating green deserts where little else will growCABI
Parthenium is native to the American tropics, but it was accidentally introduced to other continents and now severely threatens native biodiversity in Africa, Asia and Australia. Its resilience enables it to grow almost anywhere and it spreads rapidlyCABI
The Parthenium beetle is used as a natural control against Parthenium. The insect is also known as the Mexican beetle in reference to its country of origin. It eats the plants leaves, curbing its growth and flower productionCABI
Living creatures have always moved at different rates around the planet. But human transport can rapidly carry animals and plants around the world. Those who thrive in new places will irreparably change local biodiversity.
In East Africa, the proliferation of alien plants such as Opuntia stricta, Prosopis and Parthenium, all captured in this photo gallery, threaten the livelihoods of farmers and rural communities.