Kenya faces devastating Prosopis invasion: What can be done

By Purity Rima Mbaabu. Originally published on The Conversation.

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Prosopis in Lake Baringo, Kenya. Photo: ©CABI

Woody plant species have been deliberately introduced into many arid and semi-arid regions across the world as they can help combat desertification and provide resources – like fuelwood – to the rural poor. But some of these alien trees and shrubs have become invasive, having devastating effects on other species as well as people.

This is big problem in the mainly arid Baringo County, in Kenya’s Rift valley as well as other counties north, east and south of the country.

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Scientists recommend measures to contain rapid woody weed spread in Baringo County, Kenya

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A team of international scientists, including CABI’s Dr Urs Schaffner, have recommended ways to manage the devastating spread of the woody weed Prosopis juliflora, where in Baringo County, Kenya, its coverage rapidly increased by 2,031 percent in just 28 years.

PhD student Purity Rima Mbaabu, affiliated to the University of Nairobi and co-supervised by Simon Choge, Kenya Forestry Research Institute, Dr Sandra Eckert, Centre for Development and Environment, University of Bern, Switzerland, Profs. Maina Gichaba and Prof. Daniel Olago, University of Nairobi, and Dr Schaffner, is lead author of new research which states that the rates of Prosopis invasion in Kenya are a ‘major threat to the environment and rural people’s livelihoods.’

The study calls for the ‘urgent implementation of coordinated and sustainable Prosopis management in Baringo County and other invaded areas in East Africa’.

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New study reveals the massive ecological and economic impacts of woody weed invasion in Ethiopia

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A Prosopis clearing along the Awash river

CABI scientists have revealed the massive ecological and economic impacts that the invasive alien tree Prosopis juliflora has had across the Afar Region of north eastern Ethiopia.

Dr Urs Schaffner, who is supervising lead author Mr Hailu Shiferaw for his PhD studies, contributed to the Science of The Total Environment published research which shows that the devastating Prosopis was a major reason for losses in annual ecosystem service values in Afar Region estimated at US $602 million in just 31 years.

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CABI helps map ferocious speed and likely cause of woody weed spread across Ethiopia

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Riverbank invasion of Prosopsis

CABI scientists have helped map the ferocious speed and probable cause of a devastating spread of the invasive alien tree Prosopis juliflora (Swartz DC) across an area equivalent to half of neighbouring Djibouti in the Afar Region of north eastern Ethiopia.

Dr Urs Schaffner, who is supervising lead author Hailu Shiferaw for his PhD studies, contributed to the Scientific Reports published paper ‘Modelling the current fractional cover of an invasive alien plant and drivers of its invasion in a dryland ecosystem’, which shows that the Prosopis invaded 1.2 million ha of grassland/shrubland in just 35 years.

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Tackle invasive species to restore degraded landscapes

By Gilbert Nakweya
Reblogged from SciDev.Net

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Prosopis and Lantana, two invasive woody shrubs that have been encroaching on Kenyan grazing and agricultural lands. Copyright: Panos

Invasive alien species should not be used in restoring degraded landscapes as their costs outweigh their benefits, experts say.

Invasive alien species, according to the Convention on Biological Diversity, are plants, animals and other organisms that are non-native to an ecosystem, and may adversely affect human health and the environment, including decline or elimination of native species.

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Why Prosopis no longer ‘pays’ as a prospect for positive environmental and socio-economic productivity

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In the late 1970s and early 1980s the group of closely-related woody plant species and hybrids known as Prosopis were seen as a ‘saviour’ for millions of pastoralists and agro-pastoralists in East Africa whose very livelihoods were threatened by the degradation of dryland ecosystems spurred on by overgrazing, and by deforestation and a shortage of firewood.

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Could invasive plant management prevent the spread of malaria?

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CABI scientists have joined an international team of experts who suggest that the large-scale management of a range of some invasive plants could hold the key to reducing the spread of deadly malaria.

Dr Arne Witt and Dr Sean Murphy worked with scientists from the University of Illinois, The Ohio State University and the Fundación para el Estudio de Especies Invasivas (FuEDEI) in Argentina, to conduct a review of existing studies which looked at how mosquitoes are attracted to both land and water-based invasive plants such as water hyacinth, floating pennywort and prosopis and how best these invasive plants can be managed.

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