By Mohamed A. Awale
This short article is deals with recent invasion of dangerous alien plant species (Prosopis juliflora) in the drought-prone eastern low lands of Ethiopia and its current and future environmental implications. As I have discovered myself in the last visit, it has successfully colonized large swaths of area from Jijiga region to the Awash valley and beyond, thereby ravaging native vegetation and environment in which the livelihood of millions of subsistence farmers and pastoralists dearly dependent on it. One can’t even necessarily rule out at this point whether the current drought and famine crisis in the country was exasperated by the aforementioned invasive species and partial collapse of the environmental well-being in general.
So far, much has been written about the recent drought impact and famine news in Ethiopia and Somalia. The drought affected at least 15 million Ethiopian souls while the subsequent floods distressed millions more, according to sources of various United Nations’ agencies and other NGOs tasked to assist myriad of global humanitarian crises. The drought disproportionally ravaged parts of Ethiopian Somali Regional State like Siti zone. In the case of Somalia proper, and especially in the Awdal and other regions, the number of people impacted could be millions even though there are no reliable figures due lack of legit and responsive administration. As it turned out, the secessionist hardcore in the enclave was more concerned with marketability of their perennial and illusive clannish project over extending a helping hand to the drought victims and captive communities living in those regions.
The noted extensive disaster was partly due to natural phenomenon of El Nino weather pattern, and partly due to a man-made one through political, economic and environmental mismanagement over the years. This short comment exclusively deals with the environmental aspect vis-a-vis current drought exasperation. It especially concerns with an emergence of potent and alien plant species (Prosopis juliflora sp.) that recently spread over vast grazing land in the region at the expense of the native vegetation, which pastoralists and their livestock are so much depended on it. This topic is by no means detached in any way, form or shape from other dismal socio-political issues since bad polities or anarchic status its self has often crippling and corrosive manifestation on all facets of public life, economics and administrative bodies of a given jurisdiction. It is like whenever an organ of the human body is infected with disease and the rest of body parts follow suit and eventually the patient succumb to said illness, metaphorically speaking.
Background and Perils of Invasive Species
The survival of majority of Ethiopia rural population, whether pastoralists or subsistence farmers, is precariously dependent on the environment and its natural cycles. There is abundance of local flora and fauna that sustains their livelihood rhymes over the centuries. Native plant and animal species are extremely adapted to the local conditions without exception such as weather conditions, resistance to pests, soil type, water requirement and other anthropogenic interactions. In other words, it is the product of millennial evolutionary product in distinctive geographic settings. Hence, the natural ecosystem remains fairly in a state of equilibrium unless some external factors tips off the in-situ evolutionary balance, and mostly for the worse. And when that happens, it has serious implications on the food chain and health of the environment in general. For instance, an introduction of non-native plant, animal or microbial species into a given environs is a prime example of some well-recorded environmental devastation episodes in the past history. Ever have a clue as to why stubborn immigration officers in the western capitals stop people in airports in search for someone carrying of foreign plants and animals? Or ever heard of the history of the European rabbit infestation episode in Australia in the 19the century or the recent invasion of African killer bee in South and North America? Or as to why all these precedent cases are meticulously documented and scientifically studied?
To the point, it is all about due diligence and protection of native environs and natural resources of these nations from spread of exotic organism and diseases, which could compromise any country’s developmental, public health and socio-economic status. An out of control invasion foreign species into new territory has serious and known ecological consequences. The invasive Prosopis sp. shrub will probably be soon listed to be among the top invasive and environmentally destructive plant recorded in the world, if not already have done so by the natural scientists. It is unfortunate now that the natural ecosystem of both Ethiopia and Somalia fallen victim to this environmental degradation case due to short-sightedness of its regime, or its absence thereof, in the case of the decade-long comatose status of Somali ex-republic.
Notes on Prosopis and Its Invasive Properties
Prosopis juliflora species is perennial Angimnosperma or flowering plant of leguminosea family, including the common beans, and it is noxious, invasive shrub in some parts of the world. It is native to the tropical and sub-tropical of South America. By the way, the success of any invader plant species in new environ depends couple physiological and biological adaptions, etc. such as 1) the amount of seeds produced, means of dispersion and durability; 2) competitive edges for water, soil nutrients, sunlight, etc.; 3) the absence of biological control or natural enemies in the new territory; 4) allopathic traits– secretion of chemicals that suppress the growth of other plants. It seems that prosopis sp. to possess all of the above cited main characteristics. It grows up to 12 m height. It produces thousands of seeds starting from early stages that could remain dormant in the soil up to ten years and seeds extensively dispersed through animal manure, flood and winds to cover wider geographic area. Its roots also grow at the depth of 52 m in search of moisture owning of its invasive success over local plants in arid soils. The shrub had extensively invaded in Australia, India, Sri Lanka parts of Africa before, thereby decimating native flora and wrought havoc environs in every case. This invasive plant is now known as “garanwaa or geed garoob” alien or divorcee tree by Somali pastoralists’ lingoes and it is currently out of control in the drought-prone lowland regions of Ethiopia and Somalia.
How and When It Invaded
No one exactly knows when and how the weed tree invaded in the region. According to some, the invasive species was either intentionally or accidentally introduced to eastern Ethiopia in the late 1980s by various NGOs involved in humanitarian works and war refugees. It quickly established thereafter with little awareness or absence of functioning state due to the ensuing of civil wars and other prevailing chaotic political situation over decades. By the mid-1990’s, it became a major environmental problem in the eastern lowlands, including in the heart of Deridewa suburban and the Awash valley, where many pastoralists and their livestock depends on the land for their livelihood. There is no established scientific evidence linking the dots yet, but one shouldn’t be surprised if the environmental degradation caused by the invader plant, couple with Ethiopian regime’s policy of land expropriation for commercial monoculture farming in the Awash basin, which diverted much of the water flow of the upstream, played crucial role in the current drought crises and famine in the country. No wonder the precious grazing low land is now littered with carcasses of dead animals and internally displaced refugee camps. The Somalia‘s situation was compounded by virtual absence government and rule of law for decades.
Time-tested Living Treasure Lost Forever
As mentioned before, any potent invasive plant species poses direct and immediate threat to the local vegetation, which are not only well-adapted to the environment but also are major component of the food chain for myriad organisms ranging from microorganisms to top predators and to humans. It is virtually interdependent and holistic ecosystem state. As far as the potential damage Prosopis weed species could do on the indigenous flora is concerned, an age-old living treasure could be soon lost in the impact forever unless an immediate environmental intervention against its invasion is put in place.
The threatened local plants have tremendous benefit to habitat and people of the affected area. They have multi-use of economic, environmental and medicinal applications for communities over the centuries. They include varied trees and grass species with crucial environmental and economic roles. A conspicuous perennial bush plant in the area belongs to various species of Acacia genus of Leguminosea family, which has nitrogen fixing properties in addition to soil and water conservation qualities. It also hosts and shelters varied organisms from roots to the canopy. Species like Acacia inilotica, A. horrida, A. arabica, etc. are among the most dominant plants in the area. These plants have multi-economic benefits ranging from firewood, timber, farm tools, shelter and medicinal use to source of food for animals and humans. They are also source of leisure products such as gum and natural dyes or disinfectant medium of artifacts and household tools. I have particularly vivid memory during my childhood whenever my resourceful grandmother run out of tea leaves or coffee chaff in the afternoon siesta and rushed to the backyard trees while still water in the kettle with plenty of milk was still boiling and came back with a handful of pink and fresh of plant fiber that was extracted beneath the dead tissues parts of acacia tree trunks. It was perfect substitute in lieu of tea leaves in the afternoon family tea sessions.
In contrast, P. juliflora has little promising ecological benefit and economic use. Its purported greenery effect and soil erosion protection factors far less outweigh than its negative impacts. It is also allegedly poisonous for domestic animal consumption if copious amount is given, not to mention suppressing the growth of other grasses for animals. What’s more, unlike the invader species, it takes many decades for these native plants to grow and mature and many more decades to produce and still remain useful. But in the presence of a noxious super competitive plant and lack of appropriate human intervention, these native floras are currently under great environmental distress and there is a danger of total ecological collapse and so does with the human livelihood that depends on it. As it stands now, there is a looming danger of irreversible and negative ecological trend unless drastic measures of control and environs reclamation are undertaken.
Control Efforts and Methods
The best control method of an invasive species in new geographic area is prevention and an early detection. As the familiar English adage goes, a prevention of the disease is better than its cure. Once exotic species establishes successfully its self in a new territory, it is hard to stop, let alone to eradicate. The best viable option is to control and manage to limit the damage upon environment and native species. There are varied ways and methods of control measures used against a given invasive plants depending on extent of invasion, cost effectiveness, environ sensitivity and so on. It can be mainly mechanical, manual chemical or biological nature.
The mechanical control approach like the use of fire and other physical removal methods are best applicable in a medium to small scale infestation cases and non-sensitive environs. Manual method is only suitable for very limited area and mainly on the tender seedling stages of the plant and it is very tedious and labor intensive activity. That leaves the chemical methods such as the use of selective herbicides and biological control the best cost effective options in large scale infestation scenario. Note that chemical control measures are the best options in terms of the cost and timely efficacy, but environmental sensitivity factors should be taken into account as well since chemical compounds could pose long-term adverse effects on the soil, water and local organisms. Given the environmental fragility and the scale of invasion currently poses by Prosopis juliflora in the region, it would require at least a combination of chemical and biological control to minimize the ongoing devastation. But there is a need of an extensive field studies and experimentation first to devise an effective control mechanism and the sooner the better.
Thus, the logical question now is whether some efforts have been made to address this pressing environmental issue on the part of the local/central regime and academic community in Ethiopia. Hardly that is the case until now. It is encouraging to find out few field studies and scholarly work conducted Addis University in the Awash National Park, but the regime has shown no sense of urgency whatsoever to combat against such environmental menace so far. It will take a whole different vision and a policy approach to confront the issue, I suppose. By the same token, expect nothing sort of credible action, be it administrative or academic nature, taken by the anarchic Somalia. And especially this is true for the beleaguered secessionist heaven of the so-called Somaliland region, where droughts and species invasion devastated much of the land. Turns out, they have been suffering from existential and far worse drought of leadership and ideas for decades with no end in sight.
Mohamed A. Awale
Email:Moe-awale@hotmail.com