European Stars and Stripes (Newspaper) - February 9, 1993, Darmstadt, Hesse                              Troubled Wate River ecosystems face threat from Many sources rowing Waters dynamic ecosystem As Rivers and streams meander overflow their Banks and create Short lived Oxbow lakes they Taston a Patchwork of Plant and Marrial habitats both a aquatic and terrestrial. Altering their courses Over time they achieve a Long term rhythmic balance among current Shore and Loo plam that adds up to a single indivisible ecosystem. Iii h  a can Hotot to Poolt patches of Small environments occur in the Verine riparian system As a result of differences in temperature water velocity and dissolved nutrients. Organisms become specialists adapted to life in shallow riffles with Swift water deep pools or warmer streambeds. 5i i.-. -,-1 i t .50 . It by Willuam k. Stevens the new York times i pollution but from humans phys a i and ecological transform Afon of a vers and the a nnels8have been straightened Elm Nat a meandering course on which  depend for  of water from a River s flood Plain Ca Demate populations of fish that a sediments from farming run int streams and suffocate Many Small forms of aquatic life. Vacationers who Cut Down Trees to improve the vew m the. Stream then carries More sediment and becomes wide shallower and warmer making the water unfit for Many vital organisms. If you take a drive out into pretty rolling farm country nobody thinks of the farming activity As habitat destruction says j. David Allan a Freshwater  at the University of Michigan. ,. But the transformation of the landscape by agriculture is taking its toll on life in Rivers and streams As Are Urban and suburban development and the spread of exotic disruptive species of aquatic life. The transformation says Allan is far More destructive to aquatic life than Are spills of Oil or toxic chemicals. For All the one time harm they May cause these spills have relatively Little Long term Impact. And because the transformation is so much a part of deeply entrenched patterns of land and water use it is also far harder to Deal with. A 1 990 study by Larry master of the nature conservancy found that in North America 2.8 percent of amphibian species and subspecies 34 percent of fishes 65 percent of crayfish and 73 percent of mussels were imperilled in degrees ranging from rare to extinct. The comparable figures were 1 3 percent for terrestrial mammals 1 1 percent. For Birds and 14 percent for land reptiles. In the West where dams and the introduction of exotic species Are common the situation is particularly acute of 30 species of native fish in Arizona 25 Are listed As threatened or endangered according to or. . Minckley a zoologist at Arizona state University. The biotic impoverishment goes beyond the loss of Tarp pm throughout the to changes in the Channel Banks and water Quality disrupt the tint by. Meshed details of the aquatic ecology endangering the health and Teit Ihly of Many species it a streambed silts up or a Channel is widened the Walum chemistry temperature depth and movement Aie All modified farming and overgrazing Lead to destructive erosion of Banks and Runholt into the streams individual species however. Many Rivers according to Allan contain few or no endangered species yet there Are so few representatives of each species present that the ecosystem s functioning is impaired. Scientists do not know at what precise Point this thinning of life causes an ecosystem to disintegrate. But it s like a air plane Wing says John Cairns jr., an environmental biologist at Virginia polytechnic Institute. If you keep pulling rivets out the Wing is eventually. Gain Togo among other benefits riverine ecosystems create Breeding grounds for commercial fisheries carry nutrients to them and support multimillion Dollar recreational activities. In concert with wetlands they regulate the flow of water releasing it More slowly in flood times so that. More will be left for dry times. Few if any major River systems Are unaffected by the threat to ecological integrity. Sediment from farm Fields for instance has clouded the mighty Mississippi making it More hostile to Many organisms. Levees prevent the sediments from settling out naturally on the Mississippi Delta. Instead they Are channelled directly to the Continental shelf. This contributes to a sinking of the land in Southern Louisiana and releases so Many River borne nutrients into the Gulf of Mexico that Plankton growth is stimulated. The Plankton use up oxygen when they decay and die and scientists fear this oxygen depletion May harm fisheries in the Gulf. The Colorado River South of Lake Mojave has been so altered by disruption of water flow and the introduction of exotic fish species Minckley said that it has become the first major River in North America with no native fish left. Dams on the Columbia River have so interfered with Salmon migrations that one variety of Columbia Salmon has been listed by the government As  has been declare Are atoned and five More have been proposed for listing. All three of these watercourses appear on a 1992 list of North America s 10 most endangered Rivers compiled by american Rivers a Washington based conservation organization. Others include the Alsey and Tat Shenshin. River system in Alaska and Canada the great whale River in Quebec the Everglades the american River in California and the Penobscot in Maine. The list is rounded out by the Beaverkill and the Willowe Moc legendary Catskill Trout streams where american Fly fishing was born and Montana s Blackfoot the putative setting of the current hit movie a River runs through it. Habitat in lower stretches of the Beaverkill Willowe Moc system is threatened by developers cutting of Stream Side vegetation. The Blackfoot has become so degraded by Timber cutting agriculture water diversions and mining activities that the movie makers were forced to move to another location. Kevin Coyle president of american Rivers describes the four horsemen of River destruction As dams diversion of water alteration of channels and land development. Dams trap nutrients and keep them from flowing downstream. Perhaps More devastating they alter the temperature of downstream water making it either too cold or too warm and thus annihilating whole populations of insects vital to the riverine food web. One dam might not be so bad but Many dams on the same River As is common in the West repeatedly interrupt the River s natural functioning. Diversion of water for human use also widespread in the West has simply dried up Many Rivers and streams for much of the year with the result that their ecosystems Are in Coyle s words ghosts of what they used to  the straightening diking and redirection of River channels common across the country to control floods and convert flood Plains to cropland housing and highways reduce the variety of habitats critical to biological diversity. Land development often denuded Stream and River Banks of vegetation eliminating the vital transition Between the River and the Uplands. Draining land for farming or development causes water to flow More rapidly into the River Channel than it naturally would. This leaves less water to percolate into the River in drier times. If the River Channel has been straightened As Well water draining from the land moves More efficiently producing More powerful floods. These carry the increased sediments from farming and development farther choking organisms and ecosystems Well downstream. American Rivers advocates a three pronged strategy for reviving the ecosystem saving the headwaters of the major Rivers which for the most part Are already publicly owned protecting and restoring riparian zones by replanting Green strips along Rivers and working with governments to regulate water discharges from dams so they disrupt ecosystems less. Federally controlled dams Are also being examined for their environmental effects As their hydroelectric licenses come up for renewal. A number of scattered efforts to restore Rivers and streams Are being undertaken. Restoration lists have become expert at restoring streams for game fish like Trout Allan noted. What is needed now he said is a comparable Effort to restore habitat for the full panoply of riverine organisms. An ambitious Effort along these lines involves the Kissimmee River in Florida. To control flooding the army corps of engineers basically turned the twisting 103-mile Long River into a straight canal largely destroying the riverine riparian ecosystem. Now after a successful demonstration project the state of Florida and the corps Hope to restore the River s twists and turns and its ecosystem. Broader restoration of this sort is still in its infancy. But As fragile As riverine ecosystems Are Allan Points out they Are also remarkably resilient. They tend to repair themselves once the causes of their impoverishment Are removed. Silting up of str Tam diminish it aquatic lit Fine parades thai remain suspended in water reduce sunlight and Plant productivity with a Ripple effects All along the food Chain. Predatory Tish requite Good visibility to Hunt _ not file wild Rivers filled with fish Are being squeezed out by dams and is vacation Homes. Flo oust and dirt from farm Fields Are finding their Way into Rivers. Dams used to protect humans from floods often destroy wildlife habitats. Not 18 the stars and stripes the stars and stripes 19