Biodiversity and the Salmon Crisis

Biodiversity, or the lack thereof, applies to the salmon crisis in a variety of ways. From the habitat loss of logging to the construction of dams, salmon have been adversely affected by humans for over a century. In fact, until just recently, these fish have been predominately overlooked and under valued by lawmakers, industry, scientists, and the general public. But, because of the rapidly declining number of salmon in the Pacific Northwest, and the subsequent Endangered Species Act (ESA) listings, people are finally beginning to take notice of these important indicator species. Throughout the course this paper, I will attempt to address a few of the many factors responsible for this decline, including the negative impacts of human influence and the relationship between habitat loss and biodiversity decline.

Human populations have had a profound impact on salmon and their ecosystems. We have contributed, through bulldozing, paving, plowing, draining, dredging, trawling, dynamiting, and damming, to "the biggest threat to the diversity of life on the earth" (Baskin 9). Through these type of activities, people have created tremendous habitat loss, aided in the introduction of alien species into fragile communities, and caused fragmentation of natural areas throughout the world (Baskin 9). Most of this type of destruction is from developments--industrial, housing, and recreational.

Industrial developments have affected salmon in many ways. For instance, the building of dams by the hydopower industry has significantly altered the natural ecosystems of salmon in such a way that salmon are declining to a point of no return. The construction of such dams affects biodiversity "by inundat[ing] upstream floodplains, destroy[ing] running water habitat, block[ing] fish migrations, squander[ing] vast supplies of water to evaporation, and trap[ing] silt and nutrients that once flushed downriver to enrich the soils of deltas" (Baskin 74). The impacts of this kind of devestation not only affect the fish, but also the communities of people who rely on them for food and income. One such example is the Skokomish Indian Tribe that we visited on our field trip (2/21/99).

The Skokomish people, along with commercial fishing communities and others, are suffering great losses due to the dwindling numbers of Pacific salmon. This is because "the value of biological diversity is more than the sum of its parts" (Baskin 214), meaning that when salmon are destroyed, they aren't the only ones affected. Species and habitat decline can set off a chain of events influencing everything from water flow to predator/prey relationships. "Scientists may never be able to predict in advance which species are critical backup players that ought to be protected" (Baskin 27) and, unfortunately, "the loss of a single species may result in a widening circle of extinctions and the collapse of ecosystem processes" (Baskin 44).

Another  

"Clearly, restoring forested corridors could do much to hold nutrients and sediments on the land and improve the quality of lakes, rivers, and wetlands" (Baskin 91).

 excess nitrogen leads to extra fertilizer which lowers plant diversity. Elevated nitrogen levels in the ground allow for nitrates to infiltrate nearby streams thereby decreasing water quality and impacting salmon. (Baskin 129).

"Often, influential organisms disappear as a side effect of land clearing or other direct human alterations of the landscape" (Baskin 159).

"Along inland rivers, for instance, losses or changes in vegetation along the banks and in the floodplain can dramatically alter the river channel and the riverine landscape" (Baskin 174).

"the highest biological productivity on the earth is concentrated in the coastal plain and offshore zone... Yet, 60% of the human population lives on the shore side of this zone, and their numbers are projected to double with in two to three decades" (Baskin 175).

"Creating something that looks like a wetland, that contains the right water levels and the right plants for the region, seems easy enough, but putting all the pieces in place has proven to be surprisingly difficult" (Baskin 210).

"When Zedler examined coastal mitigation projects..., she found no instance where ecosystem functioning had been successfully duplicated or where endangered species had been 'rescued from the threat of extinction'" (Baskin 211).

"There is no evidence that these restored wetlands can re-create fully functioning ecosystems, and they cannot be relied upon to maintain biological diversity" (Baskin 211-212).

"As for the earth's dwindling stock of natural and seminatural landscapes, it would be far less costly to preserve robust natural systems rather than count on being able to piece them back together after they've been torn apart" (Baskin 212).

 "When water is slowed by dams, sediment settles out,...keeping rocks and gravel in much of the streambed free of sediment" (Baskin 97).