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.
The Baringo district northwest of Nairobi is one of the regions in Kenya where a number of mesquite species, Prosopis spp., were introduced some 40 years ago as part of poverty alleviation efforts. The trees were intended to provide, among other benefits, additional income.
Today Baringo is one of the most heavily invaded regions in eastern Africa, with severe consequences for the rural communities. As part of the kick-off meeting of the recently launched, Swiss government funded R4D (research for development) project called “Woody Weeds”, the project team visited the district, one of the case study areas in the project.
During this two-day visit, two communities were visited which suffered from high Prosopis invasion levels. These communities gave an interesting first insight into the dilemmas that have arisen due to Prosopis invasion. The first community we visited utilizes Prosopis for charcoal production and hopes to benefit in the future also from selling Prosopis wood to a local power plant; by utilizing this invasive species the community members gain some financial benefits and at the same time reduce the impacts of this plant on their land.
Irrespective of how the local communities deal with this invasive species, one of the main challenges in management is to find ways to slow down or reduce the spread of Prosopis and mitigate its negative impacts in Baringo (and elsewhere). While the government of Kenya supports local communities in utilizing Prosopis, there is, so far, little scientific evidence that utilization indeed slows down or even stops the spread of this aggressive invader.
One of the key tasks of the “Woody Weeds” project will therefore be the evaluation of the impacts on the environment and rural livelihoods of the various management options against Prosopis and other woody invasive species, such as management by utilization, physical, chemical or biological control, or doing nothing, and to inform decision-makers about the key findings.
Urs Schaffner, CABI
A conversation with Dr Arne Witt
The recent outbreak of Ebola virus disease in West Africa made headline news around the world. During the outbreak this fatal disease, endemic to parts of Central and West Africa, rapidly spread from Guinea, Sierra Leone, and Liberia to other countries in the region such as Nigeria, Mali and Senegal and then further afield to the USA, UK and Spain, mainly through infected health workers. This prompted decisive action from governments around the world and led to the implementation of strict controls at most national points of entry – as a result of this action and increased awareness, the further spread of this disease was effectively halted. No new infections have been reported for a number of months now but the cost has been significant – more than 10,000 people lost their lives, mainly in Guinea, Sierra Leone, and Liberia. However, it is highly probable that without significant interventions the costs could have been far higher. For example, the outbreak of bubonic plague or Black Death in Europe in the 17th century resulted in the death of 34 million people. The accidental introduction of potato blight, a crop disease which affects potatoes, from the Americas to Ireland in the mid-1800s contributed to the starvation of about 1 million people. Rinderpest, a disease affecting livestock was accidentally introduced to Africa from Asia in the late 19th century resulting in the deaths of, it is claimed, a third of the human population of what is now Ethiopia and two-thirds of the Maasai, an ethnic group of pastoralists in East Africa who are totally dependent on livestock. We may ask what Ebola, potato blight and rinderpest have in common – well obviously they have all have had a devastating impact on humanity but what binds them all together is that they are all INVASIVE ALIEN SPECIES (IAS). Fortunately, due to concerted efforts by a range of agencies rinderpest has been eradicated from the planet but as a result of increased trade, travel and tourism more and more species are being moved around the world and many are establishing and are continuing to have devastating impact on livelihoods. Continue reading
CABI, together with Tmax Productions, have produced a video called the ‘Green Invasion – Destroying Livelihoods in Africa.” The short film (approx. 7mins long) details how invasive weeds are impacting on the lives of rural communities in East Africa.
Although a large number of non-native species have become invasive in the region, this film focusses on four of the most problematic species namely Chromolaena odorata (Devil weed), Parthenium hysterophorus (famine weed), Prosopis juliflora (Mathenge) and Opuntia stricta (erect prickly pear). The excellent footage shows the extent of weed infestations with accounts from community members on how these invasive plants are destroying the natural resource base on which they depend. It is clear that invasive weeds are destroying traditions, cultures and a way of life for millions of people on the continent.
However, all is not lost. The film notes that if effective management programmes are implemented, including biological control, we can make a difference to many people’s lives.
Although of general interest, the film is intended to raise the profile of invasive species and their impacts on livelihoods amongst donors and governments. We need them to take action and provide support for initiatives to manage one of the biggest threats to economic development on the planet.
CABI Regional Coordinator, Invasives (Africa & Asia)