Environmental Problems, Their Causes, and Sustainability 1

carcasses on the forest floor. As they decompose thecarcasses help fertilize the forest and provide food fora variety of insects and other scavengers. Anotherstudy indicated that trees in forests along streams inthe Pacific Northwest with healthy salmon populationsgrow up to three times faster than those alongstreams without salmon.Thus such forests and salmon need each other forgood health. Since the dams were built, the ColumbiaRiver’s wild Pacific salmon population has droppedby 94% and nine Pacific Northwest salmon species arelisted as endangered or threatened. The dams are notthe only cause of this decline. Other factors includeoverfishing of salmon in the Pacific Ocean, destructionof salmon spawning grounds in streams by sedimentfrom logging and mining, and withdrawals of waterfor irrigation and other human uses. Also, the lack ofshade in salmon spawning streams where all of thetrees have been cut makes the water too hot for survivalof salmon eggs.Commercial fishing operations have modified thewild salmon’s natural cycle by using salmon ranching,a form of aquaculture in which salmon eggs andyoung are raised in a hatchery and then released (Figure13-14, right). But ranch salmon that escape and interbreedwith wild ones reduce the genetic diversity ofthe wild fish and their ability to survive.In 1980, the U.S. Congress passed the NorthwestPower Act. It has two main goals, which often conflictwith one another. One was to develop and implementlong-range plans to meet the region’s electricity needs.The other was to rebuild wild and hatchery-raisedsalmon and other fish populations.Figure 13-15 lists some of the strategies that havebeen used to help restore wild salmon populations.The federal government has spent over $3 billion inefforts to save the salmon but none have been effective.Environmentalists, Native American tribes, andcommercial salmon fishers want the government toremove four small hydroelectric dams on the lowerSnake River in Washington to restore salmon spawninghabitat. Farmers, barge operators, and aluminumworkers argue that removing the dams would hurt localeconomies by reducing irrigation water, eliminatingcheap transportation of commodities by ship in theaffected areas, and reducing the supply of cheap electricityfor industries and consumers.Can this wild salmon restoration project work? Noone knows because it will take decades to see whetherthe salmon populations can be rebuilt. Despite problems,this program demonstrates that people with diverseand often conflicting economic, political, and environmentalinterests can work together to try newideas and develop potentially sustainable solutions tocomplex resource management issues. It is an exampleof a large-scale reconciliation ecology project.Critics of this expensive salmon restoration programargue that populations of wild salmon are stablein Alaska, so we should not care that wild salmon aredeclining in the Pacific Northwest. They also contendthat the economic costs to the hydroelectric power,shipping, and timber industries and to farmers andconsumers exceed the value of saving wild salmon.Some have worked to restore salmon populations inspecific streams (Individuals Matter, below).xHOW WOULD YOU VOTE? Should federal efforts to rebuildwild salmon populations in the Columbia River Basin be abandoned?Cast your vote online at http://biology.brookscole.com/miller14.The Man Who Planted Trees to Restore a StreamINDIVIDUALSMATTERIn 1980 heart problemsforced JohnBeal, an engineerwith the BoeingCompany, to takesome time off. Toimprove his health he began takingdaily walks. His strolls took him bya small stream called Hamm Creekthat flows from the southwest hillsof Seattle, Washington, into theDuwamish River that empties intoPuget Sound.He remembered when thestream was a spawning ground forsalmon and evergreen trees lined itsbanks. Now the polluted streamhad no fish and the trees weregone.He decided to restore HammCreek. He persuaded companies tostop polluting the creek and hauledout many truckloads of garbage.Then he began a 15-year project ofplanting thousands of trees alongthe stream’s banks. He also restorednatural waterfalls and ponds andsalmon spawning beds.At first he worked alone, butword spread and other peoplejoined him. TV news reports andnewspaper articles about therestoration project brought morevolunteers.The creek’s water now runsclear, its vegetation has been restored,and salmon have returnedto spawn. His reward is the personalsatisfaction he feels abouthaving made a difference forHamm Creek and his community.His dedication to making the worlda better place is an outstanding exampleof the idea that all sustainabilityis local.270 CHAPTER 13 Sustaining Aquatic Biodiversity