The foreign species -- including some that have arrived by
accident -- could also harm fragile African economies by killing
off native plants and animals, according to a report delivered
to more than 100 environmental ministers at an annual meeting.
"The damage caused by alien invasive species to African wetlands
runs into the billions of dollars annually," said Geoffrey
Howard, who cowrote the report prepared by IUCN-World
Conservation Union. "The impact of these species is only just
The meeting of the U.N. Environment Program is focusing on how
to reconcile the economic needs of poor countries with the needs
of the environment.
Louisiana crawfish were taken to Africa years ago to be bred on
aquaculture farms as speciality food. But the voracious eaters
have wandered into the wild and are responsible for disappearing
water lilies and other vegetation in eastern and southern
Africa, the report said. The crawfish are also threatening many
species of snails and small fish, and their habit of burrowing
can damage dams and reservoirs, the report said.
The damage caused by foreign species can slow nations' efforts
to cut poverty rates, said Klaus Toepfer, the executive director
of the Nairobi-based U.N. program.
Some alien species, like the crawfish, are taken to foreign
locales on purpose; others arrive by accident, often in the
hulls of ships. And once they arrive, many species spread
quickly because they have no natural predators.
The South American water hyacinth, which can double in size in
less that two weeks, produces large flowers on green pads that
can block sunlight and kill plant and animal life below. The
plant has long been a plague to fishers and people living around
Lake Victoria in central Africa, the world's second-largest
In Uganda, a hyacinth infestation threatens to block turbines of
the economically important Owen Falls hydroelectric plant, the
report said. Lake Kariba in Zambia and Lake Chivero are also
dealing with heavy hyacinth growth, the report found.
Foreign Plants And Animals Threaten African Wetlands
Matthew Rosenberg, Associated Press, 6th February
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