As one goes deeper and deeper into the Awash Basin and the Afar state of Ethiopia, it becomes clear to spot small tree coming out on the tip of the environment only to give it a greenish view to the Basin’s landscape.
This also poses a question in one’s mind that how come, of all the plant species, this particular shrub takes control of the arid lowland area and gives the impression as if the if the rainy season has just ended there? But there is another side of the story.
Prosopis juliflora, the evergreen shrub, which is dominating the lowlands of Afar and the Awash Basin, is one of the most invasive alien species causing economic, social, and environmental harm in arid and semi-arid areas of Afar. The plant which was introduced to help protect the environment has turned out to be threating the livelihood of the community it was supposed to help.
Various studies indicate that the plant is spreading rapidly in the area, and is in particular threatening pastoral and agro-pastoral livelihoods. One such view is held by Dr. Tena Alamirew of the Water and Land Resource Center (WLRC) at Addis Ababa University. Last week, he happened to be a facilitator of a daylong visit to the Awash Basin for a crew of journalists who came from four Nile Basin countries to attend a media training workshop on Climate, Water and Security in the eastern Nile river basin in Bishoftu town.
Tena seems to be concerned about the shrub’s effect on pastoral ways of life and the environment that he took some time to give a brief explanation about its effects while the crew was on way to attend an Awash Basin Office press conference about the climate-induced flood and drought in the basin.
Prosopies was first introduced to the middle Awash in the late 1970s and early 80s as plant material that can grow under arid and dry climate. There was also hope that it could resist soil salinity but ended up to become a threat to the environment.
Back in April, scientists from the Center for Agriculture and Bioscience International (CABI) revealed the massive ecological and economic impacts that the invasive alien tree Prosopis juliflora has had across the Afar state of northeastern Ethiopia. The CABI made the claim based on Hailu Shiferaw’s PhD study entitled ‘Implications of land use/land cover dynamics and Prosopis invasion on ecosystem service values in Afar Region, Ethiopia.’
The research showed that the devastating Prosopis was a major reason for losses in annual ecosystem service values in Afar Region estimated at 602 million USD in just 31 years. Between 1986 and 2017, the weed spread at a rate of 31,127 hectares per year while grassland and bush-shrub-woodland declined at a rate of 19,312 hectares and 10,543 hectares per year respectively.
Dr. Tena Alamirew tells The Ethiopian Herald that the major reason for introducing the plant was its ability to easily grow under dry conditions. It was also considered useful in converting sun light energy into biomass. At the earlier stage, it was also believed the small tree could modify the micro-climate. “The Prosopis has substantially reduced the effects of the windy weather condition in the area.”
There was also hope that it could be used for the production of charcoal which later on found to be unsustainable because of social issues and the fact that Prosopis is not an ideal plant for charcoal production.
But in reality, the invasive Prosopis has been causing substantial negative impact. “The primary negative impact is that, although it was intended to easily grow in arid areas, Prosopis prefers fertile and wet areas to grow,” Dr. Tena says.
“The small tree invades grazing lands. This means there is no grass growing under. As a result, the whole cattle population has been significantly affected.” Again, besides preventing animal mobility, the small tree is harboring wild animals to attack the cattle, goats and so on.
As to Dr. Tena the disadvantages very much outweigh the advantages. The Addis Ababa and Haramaya universities have in collaboration worked on socioeconomic impact [study] and on the perception of the communities.
“One can generalize that if they get the opportunity, the Afar community would prefer for the Prosopis to be totally removed,” he says adding, “According to the locals, the two major challenges they are facing currently are water shortage and Prosopis.”
In the past, different non-governmental organizations tried to promote the utilization of Prosopis for charcoal production as a means to control it. They have also introduced other mechanisms like bulldozers to mechanically cut and remove the tree.
The problem is the primary agents that stimulate the reproduction of Prosopis are the livestock themselves and the wild animals. “If you have a good grazing land, they will automatically carry the seeds in their dung and drop it [there]. After one to three years, the whole Prosopis would come again,” says Dr. Tena.
Open communal access to grazing land is also another challenge. “This means that everybody feeds their cattle in the open land. But had we been able to introduce and organize communal management, the Prosopies would have been easily controlled at the earlier stages.”
During the Growth and Transformation period, the Afar regional government proposed a strategy to remove the plant from 1.2 to 1.6 million hectares of land. “But because of the government restructuring, it is difficult to single out which body is coordinating or leading the effort,” he says.
METEC and Dire Dawa National Cement have also proposed to generate electricity from the biomass but have not been materialized. WLRC, in collaboration with stakeholders, is actually promoting physical removal. A chemical that is found to be efficient in killing the small tree has been tried.
“Thus what is coming ahead is selling the idea to the government that this method is effective in highly invaded areas. But I think getting the license to import those chemicals is going to take some time. Tena also emphasizes on the importance of awareness creation in areas that are found to be in the front line of the invasion.
Zebediyos Selato, Plants Protection Directorate Directors at the Ministry of Agriculture on his part says Prosopis juliflora is of two kinds and unfortunately the one introduced in Ethiopia is the one with the thorn and has brought about undesirable consequences on the community, cattle and the environment.
Prosopis also has an Allelopathic Effect that the toxic chemicals that the tree produces obstruct the growth of other plants. As it is difficult to physically remove it, the Ministry has been adopting a method of control by utilization.
“We have been encouraging the utilization of the tree for various social and economic purposes. But it has not been successful at the desired level” But the best option is to adopt biological method (natural enemies) by reproducing insects that consume its seeds, adds Zebediyos. The Ethiopian Agricultural Research Institute Council Secretariate is also coordinating stakeholders and higher learning institutions to come up with a solution.
However, Tena fears what would happen to the whole pastoral way of life and indigenous trees such as acacia in very few years time if the invasion is allowed to continue.
“We have really lost substantial land in Afar. The plant is also emerging in southern Ethiopia for instance in Lower Omo area and Borena, he says. “I think it would be important to organize a kind of a task force that will properly understand the threats to come up with feasible solutions.”
The Ethiopian Herald, December 19/2019
BY ABIY HAILU
