Pahsimeroi River Watershed
Western Watersheds Project has filed a 60-day Notice Letter to the Salmon-Challis National Forest, the Bureau of Land Management, the National Marine Fisheries Service and the US Fish & Wildlife Service in regard to failures to comply with the Endangered Species Act.
The Notice Letter involves Forest Service and BLM authorization of livestock grazing that negatively impacts streams that provide habitat for Bull Trout, Chinook Salmon, and steelhead trout. These letters address grazing mismanagement on the Pahsimeroi River watershed of the Salmon-Challis National Forest and the Challis BLM Field Office.
The Pahsimeroi River, a tributary to the Salmon River, is home to populations of Upper Columbia River bull trout, Snake River spring/summer Chinook salmon, and Snake River Basin steelhead, all listed as threatened species under the ESA.
The Upper Columbia River bull trout was listed as threatened in 1998. Bull trout are found in the Pahsimeroi River and many tributaries, including the East and West Forks of the Pahsimeroi River, Mahogany Creek, Burnt Creek, Big Creek, Patterson Creek, Falls Creek, Morse Creek, Morgan Creek, and Cow Creek. A 2008 status review describes the threat rank to the Pahsimeroi core area population as “substantial” and “imminent,” and determined that continued listing as threatened was warranted.
The Snake River spring/summer Chinook salmon was listed as threatened in 1992. Critical habitat was designated in 1993 and revised in 1999. The Pahsimeroi River and many tributaries serve as designated critical habitat for this species. The number of Chinook salmon in the Pahsimeroi River and its tributaries remains significantly depressed compared to historic levels, and a 2005 status review for the species stated that it was still below abundance levels necessary for recovery and remained at risk of becoming endangered in the foreseeable future.
The Snake River Basin steelhead was listed as threatened in 1997, and critical habitat was designated in 2005. The Pahsimeroi River and several tributaries serve as designated critical habitat for this species. Wild steelhead populations are significantly depressed from historic levels, and a 2006 status review determined that the Snake River Basin steelhead remains at risk of becoming endangered in the foreseeable future and population abundance is well below recovery targets.
These species’ populations in the Pahsimeroi watershed are greatly depressed from historical levels due to irrigation withdrawals, habitat degradation, elevated temperatures, and other factors. One common factor contributing to the endangerment of all three listed species is livestock grazing. The species require stable stream channels, clean spawning and rearing gravel, and complex and diverse cover. Livestock grazing degrades habitat in many ways, including by removing riparian vegetation, destabilizing stream banks, widening stream channels, promoting incised channels, lowering water tables, reducing pool frequency, increasing soil erosion, and altering water quality. These effects reduce cover, increase summer water temperatures, promote formation of anchor ice in winter, and increase sedimentation into spawning and rearing habitats. An additional way livestock can harm listed fish is by directly trampling on redds (nests), which contain thousands of eggs. For this reason, livestock should not have direct access to streams, particularly during spawning and incubating periods.