The history of land use on Alaska's Kenai River and its implications for sustaining salmon.
详细信息
文摘
The Kenai River Watershed (KRW),in south-central Alaska,is famous for its salmon. Urbanization along the lower river damages habitat and stresses these valuable fish. Are the river's salmon runs sustainable if recent land-use trends continue? I used interdisciplinary approaches from environmental history and landscape science plus technologies such as geographic information systems (GIS) to describe the watershed's land-use history from 1947 to 2010 and to link land use and watershed management to the sustainability of salmon runs. Although the area appears wild compared to many salmon-producing watersheds in other states,it has a long history of intense use and habitat degradation. Over the past 60 years the central Kenai Peninsula showed patterns of intensive riverfront recreational use,coupled with rural exurban sprawl in the uplands. Historic damage to salmon habitat included trampled riverbanks,bank hardening,dredged canals,diverted creeks,toxic spills,poorly built roads with impassable culverts,and the Cooper Lake Dam. More recent threats include cumulative effects,fishing pressure,climate change,invasive species,off-road vehicles,and potential septic leaks. Comparing the Kenai River case with land-use histories in 60 other salmon-producing watersheds suggested that the salmon runs are at risk due to delayed,cumulative effects of development and potential climate change. However,since the late 1980s people have taken unprecedented and progressive steps to protect healthy watershed habitat and reverse past damage. The high level of community commitment and reserves of undamaged habitat provide hope that Alaskans may learn from the grim fate of wild salmon around the world,and take better care of their salmon habitat. I concluded that the sustainability of the salmon runs hangs in the balance and offer a list of recommendations to maintain or enhance the resilience of the system.