7994 - Laserfiche WebLink

Home Browse Search

indicates that a substantial number of the sub-basins have stream habitat in good to extremely degraded condition (Table 3). There was also a significant level of uncertainty relative to the trend in condition (Table 4). Specific comments pointed to channel dewatering, changes to channel morphology and increased sediment as major factors influencing habitat. The status of Yellowstone cutthroat trout within National Forest lands in Idaho indicates a somewhat higher (53%) occupancy (Table 1). This assessment did not specify population life history and abundance characteristics for Yellowstone cutthroat trout residing in Forest habitats. There was, however, an effort to identify habitat status and factors contributing to current status (Tables 3 and 4). It is important to note that information contained in Tables 3 and 4 may at times seem inconsistent. For some sub-basins more than one condition and/or trend was identified and for other sub-basins condition and/or trend may have been omitted. The same is true for the information associated with factors linked to degradation and the land-use activities associated with those factors. There was also one instance where a sub-basin included two Forests. Of the 19 sub-basins which contained aquatic habitats on National Forests, 47% were identified as having good habitat condition with 37% having a fair rating and 16% having a poor habitat condition (Table 3). For the National Forests, in general, dewatering, changes in temperature, channel modification, limited large woody debris and sediment were viewed as the factors with greatest affect on habitat condition. The land-use that was identified as having the greatest influence was grazing followed by logging, road construction and mining. The Targhee National Forest had the highest proportion of sub-basins (7) with habitat rated as good (86%) and fair (43%). Habitat condition ratings for the Caribou National Forest sub-basins (10) included good (20%), fair (40%) and poor (20%). The Sawtooth National Forest had only three sub-basins with 33% rated as fair and 33% rated as poor. Each Forest had a somewhat different mix of factors and land-use activities which contributed to the condition ratings (Table 4). Channel modification and/or sediment were primarily associated with degraded condition and grazing was identified as the detracting land-use. Wyominq The assessment area included the Snake River drainage from the State boundary with Idaho up- stream to the headwaters and the Yellowstone River from the State boundary with Montana upstream to the headwaters. Also included were the major tributaries (e.g. Clarks Fork of the Yellowstone, Bighorn River and Tongue River) that enter the mainstem Yellowstone River's middle section. Twenty five (25) sub-basin analysis units (Table 5) were established and a questionnaire was completed for each. The mainstem Snake River was divided into two analysis units; one section between Palisades Reservoir and Jackson Lake and another from Jackson Lake to the headwaters. In addition, most of the major tributaries (Salt River, Greys River, Hoback River, Gras Ventre River, Spread Creek, Buffalo Fork and Pacific Creek) were treated as separate analysis units. The Yellowstone River assessment included sub-basins within Yellowstone National Park including a sub-basin that extended from the north Park boundary to Yellowstone Falls and an analysis unit that extended from the Falls to the south Park boundary. The headwaters above the Park were treated as a separate assessment unit. The Clarks Fork of the Yellowstone River drainage was treated as a separate unit. Within the Bighorn River drainage there were 9 sub-basins and there were 3 within the Tongue River drainage. The amount of historical Yellowstone cutthroat trout riverine habitat within Wyoming was estimated at 10,949 miles. This amount included approximately 1,569 miles of stream habitat that would have been occupied by the "fine spotted Snake River" form (Table 5). These mileage estimates are likely an over estimate resulting from the data base from which the information was taken. The particular data base used to provide the mileage information included all perennial streams including many headwater streams that likely would not support fish. Mileage information for the Clarks Fork of the Yellowstone was also included, even though, documentation indicates that the upper portion of the 17