Lake Victoria Battles Biodiversity Breakdown

NAIROBI, Kenya, December 1, 2000 (ENS) - For a lesson in how quickly ecosystems fragment across international borders, a report today suggests looking no further than Lake Victoria.

Prior to 1970, Lake Victoria, the world's largest tropical lake, had more than 350 species of fish from the cichlid family. Ninety percent of these were unique to the lake.

fishing

Fishing for tilapia and Nile perch provides a living for many of the Luo people who live along the lakeside. But resulting deforestation is jeopardizing the lake and its fish. (Photo courtesy Kenya Tourist Office, New York)
The introduction of Nile perch and tilapia caused a collapse in the lake's biodiversity and deforestation in the three countries that border the lake, Uganda, Tanzania, and Kenya.

Wood is needed to dry the oily perch, compared with the cichlids, which could be air dried. Forest clearing has increased siltation and eutrophication in the lake, jeopardizing the Nile perch and tilapia fishery - the cause of the problem to begin with.

Often the result of human intervention, eutrophication is the process by which a water body is overwhelmed by plant life and nutrients at the expense of oxygen.

While tons of perch find their way to diners in Europe, generating $400 million in annual export income, scientists document protein malnutrition among people around the lake.

"Lake Victoria illustrates how profound and unpredictable trade offs can be when management decisions do not take into account how the ecosystem will react," said Dr. John Mugabe, executive director of African Centre for Technology Studies.

"The poor, who often depend directly on ecosystems for their livelihoods, suffer most when ecosystems are degraded."

lake

Lake Victoria is the world's second largest freshwater lake covering an area of 67,850 square kilometers. This vast expanse, about the size of the Republic of Ireland, forms the headwaters of the River Nile. (Photo courtesy Kenya Tourist Office, New York)
Mugabe was commenting on World Resources "2000-2001: People and Ecosystems: The Fraying Web of Life." The report is a comprehensive assessment of the world's ecosystems, conducted over four years by 175 scientists funded by the United Nations Development Program, the UN Environment Program, the World Bank, and World Resources Institute.

It examines coastal, forest, grassland, and freshwater and agricultural ecosystems and analyzes their health on the basis of their ability to produce the goods and services that the world relies on.

These include production of food, provision of pure and sufficient water, storage of atmospheric carbon, maintenance of biodiversity and provision of recreation and tourism opportunities.

The report was presented this week in a panel discussion organized by the African Centre for Technology Studies. It marked the first time that the results have been publicly presented on the continent.

"The report paints a picture of Africa's ecosystems in serious trouble," said Professor Reuben Olembo, chairman of Kenya's National Committee on the Implementation of Environmental Management and Coordination Act.

"An important element of this report is its emphasis on human beings as an integral part of ecosystems. It is a relationship too long ignored by environmental scientists."

Statistics in the report are summarized graphically in an ecosystems scorecard. They paint a gloomy picture of over-fished oceans, creeping desertification, and destruction of coral reefs and forests.

desertification

The linear dunes of the Sahara Desert encroach on Nouakchott, the capital of Mauritania. (Photo by Georg Gerster, courtesy U.S. Geological Survey)
Human population growth and poverty continue to drive the decline of Africa's and the world's ecosystems, says the report.

As well as Lake Victoria's plight, the report highlights discusses positive efforts to revive the hillsides of Machakos District outside Nairobi and the national effort to restore the water supply of South Africa stolen by invasive plants.

The report's managing editor Janet Overton said the case studies were chosen to highlight ecosystem problems and management at local levels. "Through these examples of success, we can identify the new heroes of the environmental movement," said Overton.

The report recommends that governments and people view the sustainability of Lake Victoria and other ecosystems as essential to African life. For too long, it says, people have focused on how many goods they can take from lakes and other ecosystems, with little attention to the services that they provide.

Essential services like habitat for other species, climate control, and nutrient recycling cannot be replaced at any reasonable price, it warns.

It calls for an ecosystems approach to managing the world's critical resources. This means evaluating decisions on land and resource use based of how they affect the capacity of ecosystems to produce goods and services.

It adds these four recommendations:

For the 30 million people who depend on Lake Victoria for food and employment, the last recommendation will be particularly welcome.