ScholarWorks at University of Montana

Montana’s wild trout fisheries and native aquatic communities depend on connectivity of aquatic habitats. For fish, connectivity (the means to move freely between streams or stream reaches) allows spawning migrations, seasonal movements and complex life history strategies to persist. However, management strategies that prioritize conservation of native fish populations (including genetic integrity) require a balance between connectivity, selective movement and, in some instances, isolation. In western Montana rivers, rainbow trout (Oncorhynchus mykiss, the predominant introduced sport fish), as well as migratory forms of native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisi), require connectivity between rivers and their tributaries in order to thrive. In other instances, physically segregating genetically ‘pure’ stream-resident trout populations (particularly westslope cutthroat trout) is essential to isolate them from hybridization with non-native salmonids and other threats. Balancing the need for both connectivity and isolation creates a paradoxical management situation. Here, I will describe the middle Clark Fork River basin in this context, summarize fisheries management plans, and provide examples of recent fish passage improvements and sustained population isolates.

The goal of the Lolo National Forest Fisheries Program is to conserve and restore native fish habitat and populations. An integral part of this goal is to build a strong program focused on removing barriers and restoring connectivity for fluvial westslope cutthroat trout and bull trout. Culverts used for stream crossings create temporary, partial, or seasonal barriers to fish passage, while others may preclude movement of fishes year-round. They can deny access to seasonally critical habitats, fragment populations, and suppress the recovery of populations following disturbance. Along with being fish passage barriers, undersized culverts can also lead to chronic stream degradation, increased erosion and sedimentation, and eventually road failures.

To address these issues, we implemented an extensive survey of all road crossings of fish bearing streams on the forest in 2002 and 2003. Crews surveyed 696 culverts on the forest. The results showed that 592 (85.1%) of the culverts on the LNF are barriers to juvenile fish passage, while 602 (86.5%) culverts are barriers to adult passage.

Attempting to address stream and population fragmentation, we have completed numerous culvert removal/replacement projects since 1995. Examples of projects across the forest include: Siegel Creek, where an undersized pipe was removed and the road obliterated above; Schwartz Creek, where two side-by-side culverts were removed, opening 5 miles of mainstem habitat; Lost Park Creek, where a 6-foot culvert at the mouth was replaced with a single-span bridge, opening up the entire mainstem; and, Surveyor Creek, where two high priority pipes were removed, opening 1 mile of habitat.

This winter (2005), we will be developing a prioritization process to help identify out-year projects and to create more opportunities to work with partners. The most significant hurdle facing us in restoring connectivity to these systems is the public acceptance of large-scale road removal projects and available funding. Through forest-wide barrier inventory and prioritization, we hope to raise awareness of the impacts of existing road systems and stream crossings, and the need for more funding to complete these important projects.

Fire, landscape-scale management projects and proposals, and regulatory drivers (TMDL) present a unique opportunity for aquatic restoration in the Ninemile drainage. The Ninemile drainage is an important fish production tributary to the middle Clark Fork. Yet is has an extensive legacy of both public and private management that has reduced and limits native fish production. Currently, Westslope cutthroat trout are distributed throughout many tributary watersheds and the upper mainstem Ninemile, but bull trout are only incidental. Non-native salmonids are also established in portions of the watershed. Channel, floodplain, and water temperature modifications from agriculture and valley development (lower 2/3 of the mainstem), coupled with extensive placer mining on the upper main Ninemile, have contributed to the incidental presence of bull trout. Also, the mid to upper portions of most publicly managed tributary watersheds have extensive road networks and associated crossing features that have chronic sediment and fish passage effects. This, coupled with past cumulative effects from vegetation management, and tributary placer activities combine to limit and fragment additional native fish production in the Ninemile watershed.

The fires of 2000 led to the first large-scale proposal for road obliteration, stream crossing improvement, and mine-site restoration in the upper half of the Ninemile drainage (Post-Burn EIS). Some of this proposed work has already occurred (stream crossing improvement), and more (road closure, crossing removal, road relocation, and mine-site restoration) is scheduled to occur in summer 2005 and beyond. Another large vegetation and watershed improvement proposal for the southeast portion of the Ninemile drainage is underway (Frenchtown Face EIS). More than 100 miles of road are proposed to be decommissioned along and up to 16 large pipe, some partial or complete fish passage barriers, are proposed to be removed or replaced. These two projects (Post Burn and Frenchtown Face) fit well with the recently completed Ninemile TMDL and watershed restoration plan that identifies watershed wide sources of pollution and pollutants, and proposal to improve watershed and instream conditions. Additional coordinated mainstem Ninemile and tributary restoration planning and proposal by land and fish management agencies coordinated with the Ninemile watershed group can help further protect and restore this important native fishery.

Nevada Spring Creek is a tributary to Nevada Creek, an impaired tributary of the Blackfoot River. Nevada Spring Creek has been the focus of several restoration projects from 1990-2004. The goal of restoration work was to restore habitat conditions suitable for native trout, specifically westslope cutthroat trout (Oncoryhnchus clarki lewisi) and to improve downstream water quality and reduce thermal stress in Nevada Creek and the Blackfoot River. Restoration of four miles of Nevada Spring Creek took place in several stages, and utilized a variety of methods including complete channel reconstruction, instream wood placement, gravel addition, shrub plantings, sod mat stacking, and riparian grazing management changes. Pre- and post-project monitoring indicates that original project objectives are being met. Temperatures have been moderated throughout the entire length of the spring creek (decreased 10-15o F), to provide the preferred range for trout. Initial fisheries surveys indicate community shifts in the upper and lower portions of the spring creek. Surveys in the upper section, a section previously dominated by brown trout, have found continued increased densities of brown trout and early signs of increased westslope cutthroat trout densities. A dramatic community shift was also detected in the lower spring creek as species diversity increased from three to six species, and a pre-project non-salmonid community shifted completely to an assemblage dominated by 85% salmonids (brown trout, westslope cutthroat and whitefish). In addition, a single bull trout was also collected, the first Montana Fish, Wildlife and Parks documented bull trout in the Nevada Creek watershed in the last 15 years.

Lost Creek is a third order stream entering the upper Clark Fork River near Warm Springs, Montana. Lost Creek’s water quality and habitat issues include nutrient loading, excessive sedimentation, habitat and flow alterations, channelization, loss of woody riparian vegetation, and fish passage barriers. Among all tributaries, Lost Creek is the largest contributor of nitrogen to the upper Clark Fork River above Deer Lodge. The Tri-State Council’s Clark Fork River voluntary nutrient reduction program lists Lost Creek as the number one priority among non-point nutrient sources in the upper Clark Fork River basin. Montana Fish, Wildlife and Parks is undertaking a major watershed restoration effort to reduce excessive nutrient and sediment discharge and improve the degraded channel condition of the lower creek. The Lost Creek watershed project involves the coordination of riparian and upland restoration activities across six ranches and 27 stream miles stretching from the community of Lost Creek downstream to the Clark Fork River. Overall,the project includes installation of two fish passage structures, corral relocation, habitat enhancement, riparian revegetation, bank stabilization, historic channel reactivation, bridge replacement, riparian fencing, and grazing management. In addition, this project will evaluate the effectiveness of various in-stream restoration techniques for improving habitat and reducing bank erosion in Lost Creek. These techniques include the use of root wads, coir logs, straw bales, tree revetments, bank reshaping, channel relocation, willow transplanting, and willow sprigging.