INVASION OF ALIEN SPECIES IN TANZANIA

Invasive alien species are those that become established in a new environment, then proliferate and spread in ways that are destructive to the biodiversity and/ or human interest. This invasion is recognized as one of the greatest threat ecological and economic well being of the planet. These species have caused enormous damage to the biodiversity and the valuable agricultural system upon which we depend, also direct and indirect health effects are increasingly serious and the damage to native biodiversity is often irreversible.

The increased trade, travel and transportation across borders have no doubt brought tremendous benefits to the Tanzanian people. However it has also facilitated the spread of alien species with increasing negative impacts. This is not only a problem in Tanzania but also the whole global faces this danger. It requires international cooperation, government efforts as well as private sectors and organizations at national and local levels.

These species are found in nearly all major taxonomic groups of organisms, they include viruses, fungi, higher plants, fish, birds and mammals. In Tanzanian there is a couple of alien species that have proven a very negative impact to the ecosystem and other native species.

Nile perch & Nile tilapia, these species have been a cause of mass extinction of vertebrates in recorded history. At least 200 fish species erased from existence by these predators Nile perch and tilapia. This specie was introduced by British officials in Lake Victoria in early 1950s as a result of the pressure of overfishing. Nile perch and Nile tilapia flourished because they had no natural predator and had plenty of prey. It ate up vast quantities of cichlid fish and responsible for driving at least 200 species to extinction in the process. Although the species have also proven a good economical impact it has also brought about indirect environmental impacts such as deforestation and infestation of water hyacinth in Lake Victoria.

Water hyacinth, this is considered the world?s worst invasion aquatic weed. It originates from Amazon basin in South America, it was introduced as an ornamental plant. Water hyacinth infestation is associated with a variety of socio economic and environmental impacts. They are responsible for increased siltation in rivers and dams, affecting quality of water and creating favorable condition for mosquitoes and bilharzias carrying snails. In Lake Victoria Tanzania water hyacinth covered up 12000 hectares in mid 1990s this disrupted fishing trade, blocked ports and landing areas. However after a long term control program the water hyacinth was effectively brought under control. Now only 2000 hectares of Lake Victoria surface is covered by the hyacinth.

That?s just to mention a few examples of alien species that have invaded in Tanzania, however a number of plants, animals, fungi, or micro organisms that are not native to Tanzanian ecosystem and whose introduction is likely to cause harm to the environment, economy and human health are many. The problem this alien species pose are in the following categories biodiversity, food security, forestry & fisheries, trade, transport and human health. The solution to these should be strengthening the enabling policy environment for prevention and management of invasion of alien species, to raise awareness of and exchange information on alien species, to implement strategies for the prevention and management of alien species as well as build capacity for sustainable alien species management.

In a world where everyone is trying to fight the adverse impacts of climate change, food security and the like I think its important to bring to our attention this alien species invading our specific ecosystem. I believed each country is a victim of alien species is high time we take note of them analyze their impacts and prevent them from causing further damage to our ecosystems. It is important to also understand that preventing alien species invasion we are conserving our biodiversity, and sustaining human livelihood.

Source

-the global invasive species programme.