Management history of eastside ecosystems: changes in fish habitat over 50 years, 1935 to 1992
Management history of eastside ecosystems: changes in fish habitat over 50 years, 1935 to 1992
复制标题
东部生态系统管理历史:1935年至1992年50年来鱼类栖息地的变化
DOI:
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发表时间:
1994
期刊:
影响因子:
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通讯作者:
L. A. Brown
中科院分区:
文献类型:
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作者:
B. Mcintosh;J. Sedell;J. Smith;R. Wissmar;S. Clarke;G. Reeves;L. A. Brown
From 1934 to 1942, the Bureau of Fisheries surveyed over 8000 km of streams in the Columbia River basin to determine the condition of fish habitat. To evaluate changes in stream habitat over time, a portion of the historically surveyed streams in the Grande Ronde, Methow, Wenatchee, and Yakima River basins were resurveyed from 1990 to 1992. Streams were chosen where the primary impacts were natural disturbance (unmanaged), such as wilderness and roadless areas, and where human impacts (managed) were the major disturbances. In addition, historical changes in land-use, stream-flow, and climate regimes were also analyzed. Many of these streams had been degraded from land-use activities (riparian timber harvest, splash dams, stream channelization, livestock grazing, and mining) prior to the historical survey. While the general trend throughout the Columbia River basin has been towards a loss in fish habitat on managed lands and stable or improving conditions on unmanaged lands, the data for these four river basins suggest there is a regional pattern to this change. Based on this information, along with data on the status of anadromous fish runs in these basins, fish habitat has shown some improvement from past abuses in eastern Washington, while continuing to decline in eastern Oregon. This appears to be the result of different land-use histories in the two regions. The river basins of eastern Washington apparently had a period of recovery after World War I from past land-use practices, as the impacts of development decreased. In contrast, river basins of eastern Oregon have been affected continuously by land-use practices over the entire development period (1850-present). From this information, it is clear that land-use practices have degraded fish habitat throughout eastern Washington and Oregon. Strategies to protect, restore, and maintain anadromous and resident fish populations and their habitat, must be based on a watershed approach that protects the remaining habitat and restores historical habitats. changes in habitat over and the current condition of in In reviewing changes in we also surveyed, with varying degrees of changing patterns of and over From this overview, we identified with give A series of reports published from 1949-1952 by the U.S. Fish and Wildlife Service are the primary basis for current estimates of the loss of anadromous fish habitat in the Columbia River basin. The reports were brief, qualitative accounts of over 8000 km of stream surveys conducted by the Bureau of Fisheries from 1934-46 (Bryant 1949; Bryant and Parkhurst 1950; Fulton, 1968, 1970; Northwest Power Planning Council 1986; Parkhurst 1950a, 1950b, 1950c, Parkhurst and others 1950; Thompson 1976). The Bureau of Fisheries surveys were undertaken with the objective of determining the condition of streams in the Columbia River basin that provided, or had provided, spawning and rearing habitat for salmon and steelhead (Rich 1948). Recently, the original field notes from the Bureau of Fisheries surveys were discov-ered. The data are now being archived and stored in the Forest Science DataBank at Oregon State University. These records are the earliest and most comprehensive documentation available on the condition and extent of anadromous fish habitat in the Columbia River basin. They provide the best available data for quantifying change and setting benchmarks for future restoration of anadromous fish habitat throughout the basin. The Pacific Northwest Research Station has been using the Bureau of Fisheries surveys, in conjunction with current surveys, to determine how the condition of stream habitat in the Columbia River basin has changed over the past 50 years. The Pacific Northwest Research Station study, conducted from 1987 to the present, has examined streams across a broad range of geological conditions, land ownerships, and land-use histories (McIntosh 1992, Sedell and 1990). the functional role of large woody in and high quality fish and and Ashkenas and 1991, and others 1991. Large woody a wide array of physical and biological functions in stream ecosystems, include providing cover and habitat complexity for storage, in-channel roughness, reducing the erosional effects of high flows, and enhancing pool development and maintenance. Many studies have shown that the loss of large woody debris reduces salmonid production and others 1987, and others 1985, MacDonald and others 1991.