Freshwater ecosystems face many other risks as well:
- Industrial discharges and agricultural and urban runoff are pervasive stresses. By the early 1990s, acid rain had caused a 40-percent decline in fish species in Canadian lakes [18].
- Overfishing, which plagues many freshwater systems, is currently driving various sturgeon species toward extinction in the Caspian Sea and its tributaries [19].
- Water diversions for agriculture and urban water supplies have rendered all native fish species in the lower Colorado River either endangered or extinct [20].
- Siltation from soil erosion has been cited as a major factor in the decline of endemic fishes in Sri Lanka [21].
- Competition from nonnative fishes in Lake Victoria has driven 200 species of native cichlids to extinction and endangered 150 more [22].
In response to these threats, concern for freshwater systems is growing. At the World Bank and other development banks that have traditionally looked favorably on dams and other major water projects, policies have shifted to emphasize a more thorough examination of the full benefits and costs of the these projects. For instance, the Inter-American Development Bank so far has refused requests to bankroll the Hidrovia project in light of its environmental impacts [23].
More positive still is a nascent trend toward restoring some damaged freshwater ecosystems. In Romania, officials at the Danube Delta Biosphere Reserve, with funds from the World Bank’s Global Environmental Facility and other foreign donors, are breaching dikes and dams that were built to convert the immense delta wetlands at the mouth of the Danube to farmland. In the United States, engineers are attempting a similar restoration at the Everglades National Park in Florida [24] [25].
To minimize further damage to freshwater ecosystems, the signatory nations to the U.N. Convention on Biological Diversity have agreed to focus on risks to freshwater ecosystems at their next meeting in 1998 (the Fourth Conference of the Parties). With the scale of water developments still growing worldwide, experts stress that the need for coordinated action is urgent.
References and notes
17. Peter Muello, “South American Water Project Hits Ecological Snags,” Washington Times (May 26, 1997), p. A14.
18. Op. cit. 5, pp. 155-156.
19. H. Reed, “Caviar Trade Threatens Caspian Sea Sturgeon,” TRAFFIC USA. Available online at: http://www.wwf.org/new/traffic/dec96/trafcav.htm (December 1997).
20. Op. cit. 5, pp. 136-137.
21. Op. cit. 5, pp. 151-152.
22. Op. cit. 3, pp. 48-49.
23. Marco Ehrlich, Environmental Specialist, Inter-American Development Bank, Washington, D.C.,
24. Marlise Simons, “Big, Bold Effort Brings Danube Back to Life,” New York Times (October 1, 1997), p. 1, sec. 1.
25. Op. cit. 9, p. 34.
