After the mysterious blockage in the Letaba River, in Limpopo, caused by the infamous water hyacinth plant, it turns out that freshwater bodies throughout South Africa have been suffering under this alien invasion for some time, Letaba Herald reports.
The water hyacinth, indigenous to South America, has been classified as the world’s worst invasive species. It spreads like a weed, covering entire water bodies with its densely woven material. The plant blocks out sunlight and drains the water of its oxygen, which leads to the death of many organisms, along with all the animals in the water that depend on them.
Humidity and temperatures congenial to the breeding of pests, parasites and bacteria are also symptoms of the invasion.
Dewald Kamffer (Ecocheck), who completed his thesis on the subject of water hyacinth as pest or product, explains what the long term effects may be if the problem is left untreated: “Worst case scenario, the river can die. If the plant covers whole sections of the river, oxygen is reduced, invertebrates, amphibians and fish will die, and the ecological system will collapse. This infestation could conceivably reach the KNP and spread as far as Massingir Dam in Mozambique – becoming an international ecological disaster.”
There are two ways to fight this: biologically or mechanically.
Pesticides and the biological approach have generally proven unsuccessful in South African waters due to the heavy metals and pollution of our water supplies and the complications with bio agents. Unleashing a swarm of killer insects to devour the invaders has undesirable ramifications for the Eco system.
The best way to combat the invasion in our context is mechanically – using manpower and equipment to physically break apart the plant clusters and remove them from the river. This can be extremely expensive, but there are various ways to do it.
However, the harvested hyacinth plant has been used to create fertilisers, organic soil additives and even bio gas. It is potentially a very useful agricultural product, whose profits could compensate for some of the removal costs.
Kamffer suggested a ‘community project’ to tackle the problem: “A collaboration between government departments would be ideal – the following departments should all take an interest: agriculture, forestry and fisheries, cooperative governance, economic development, environmental affairs, health, labour, public enterprises, public works, science and technology, small business development, tourism, trade and industry and water and sanitation.
If one or more of these departments can be convinced that the problem is real, and the solution easy with many positive spin-offs, the project should be relatively easy to start with minimal funding.
This would be an opportunity to get the departments involved and see it as harvesting a product, and creating jobs, rather than yet another expensive pest-control programme.
Successful treatment will bring life back to the water and free up the river flow again at least as far as the droughts will allow, and time will come when stakeholders who have an interest in the Letaba River face the task of collaborating on such a project.
– Caxton News Service