Warming climate may impact range of native char species
By Jason D.B. Kauffman, Idaho Mountain Express, Feb. 10, 2010
A proposal to significantly expand habitat protections for bull trout could lead to changes in how irrigation diversions, dams, logging and other potentially harmful activities are managed on federal land in the upper Salmon River watershed and other regional waterways.
It could also lead to expanded habitat restoration efforts in rivers, streams and other waterways in the lower 48 states where the federally protected fish lives.
But this and other actions meant to save the iconic species inhabiting clear, cold streams of northwestern North America may not be enough to save it from disappearing in many lower reaches of rivers due to the impacts of climate change. Many fisheries scientists predict bull trout and other cold-water-dependent fish species will find portions of these waterways uninhabitable if water temperatures climb and river flows drop as predicted.
In Idaho, bull trout occupy segments of the Salmon, Boise, Clearwater, Coeur d’Alene, Clark Fork and Kootenai river systems. The fish is also present in river systems in western Idaho and in one outlying basin spanning the Idaho-Nevada state line, the Jarbidge River system.
Bull trout are not present in the Big Wood, Little Wood or Big Lost river systems of south central Idaho. However, an isolated, remnant population is present in the Little Lost River north of Howe.
Officials with the U.S. Fish and Wildlife Service delighted fish advocates when they announced Jan. 13 their intent to expand by up to five times a 2005 critical habitat designation for bull trout occupying the lower 48 states. The fish was listed as threatened under the federal Endangered Species Act in 1999.
The proposed critical habitat expansion, developed by a team of federal scientists, is intended to provide sufficient habitat to allow for genetic and life-history diversity, ensure bull trout are well distributed across representative habitats, ensure sufficient connectivity among populations and allow for the ability to address threats facing the species.
“We intend to prioritize conservation actions in those habitats most important to the bull trout’s protection and recovery,” said Robyn Thorson, director of the Fish and Wildlife Service’s Pacific Region.
The Fish and Wildlife Service estimates that changes in forest management brought about by expanded bull trout protection efforts, such as the removal of culverts to aid in habitat connection and efforts to reduce in-stream sediment, could cost anywhere from $400,000 to $1.65 million a year. Additional changes could also be required for fish passage improvements on some 70 federal and nonfederal dams in the region.
In all, the Fish and Wildlife Service predicts management changes brought about by the critical habitat expansion could cost an additional $5 million to $7 million per year over the next 20 years.
In early 2006, Montana-based Alliance for the Wild Rockies and Friends of the Wild Swan sued the Fish and Wildlife Service over the 2005 critical habitat designation. They alleged, among other things, that the federal government failed to designate enough habitat and unlawfully excluded areas from the final designation.
Last March, the Fish and Wildlife Service notified the U.S. District Court of Oregon that the agency would seek a remand of the 2005 critical habitat rule based on the findings of an investigative report by the U.S. Department of the Interior inspector general. The report found that Julie MacDonald, a Department of the Interior appointee under the Bush administration, had extensively interfered with the final 2005 designation. She was accused of directing that large habitat areas be excluded from what had been proposed and by not allowing the inclusion of any area unless there was absolute certainty that bull trout were present.
The 1999 ESA listing covers the species’ full range in the coterminous United States in Idaho, Montana, Washington, Oregon and Nevada. Bull trout are grouped with the char, within the salmonid family of fishes. Once plentiful, bull trout are now found in less than half their historic range, according to the Fish and Wildlife Service.
Bull trout have declined due to habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, past fisheries management and the introduction of non-native species such as brown, lake and brook trout. While bull trout occur over a large area, their distribution and abundance continue to decline, and extirpation, where the species has become locally extinct, has been documented in a number of locations, state Fish and Wildlife Service biologists.
Many of the remaining populations of bull trout are small and isolated from each other, making them more susceptible to extirpation.
Most bull trout populations are migratory, spending portions of their life cycle in larger rivers or lakes before returning to smaller streams to spawn. Some populations complete their entire life cycle in the same stream. The fish can grow to more than 20 pounds in lake environments and live up to 12 years. Under exceptional circumstances, they can live more than 20 years.
If finalized, the proposal would increase the amount of stream miles designated as bull trout critical habitat in the five states by 18,851 miles and the amount of lakes and reservoirs designated as critical habitat by 390,208 acres. That includes about 166 miles of critical habitat proposed in the Jarbidge River basin, where no critical habitat was designated in 2005. In Idaho, 9,671 stream miles and 197,915 acres of lakes or reservoirs are proposed as critical habitat for bull trout.
A 2007 report from Trout Unlimited titled “Healing Troubled Waters” that discusses the impacts of climate change on fish species like bull trout states that trout and salmon are especially vulnerable to global warming because of their dependence on clear, cold water. The study states that as cold-water habitats warm, the rising temperatures will have negative impacts on the entire life history of these iconic fish—from eggs to juveniles to adults.
“Climate change is not some uncertain future problem. It is happening right now, and we see evidence in terms of reduced snowpack and earlier spring runoff,” said Jack Williams, Trout Unlimited’s senior scientist and one of the report’s authors.
The study’s authors estimate that migratory bull trout could decline by as much as 90 percent in the face of climate change. They project that annual temperatures will increase by between 2 and 10 degrees Fahrenheit over the next 100 years.
The Trout Unlimited report recommends implementing projects that place more woody debris and variable rock structure within streams and rivers. Such work helps slow fast-moving waters, provides shelter for fish and contributes to the scouring out of deeper downstream pools, where cooler waters would provide fish safe havens when summer temperatures make shallower waters too warm for their survival. The report also recommends reconnecting stream sections separated by man-made irrigation structures.
In the past few years, Trout Unlimited took part in one such project on the Little Lost River that constructed fish passage structures to bypass irrigation diversion dams and reconnect isolated bull trout populations.
Under the ESA, critical habitat identifies geographic areas that contain features essential for the conservation of a listed species and other areas that the Fish and Wildlife Service considers essential for the conservation of the species. Critical habitat designations provide extra regulatory protection to areas that may require special management, and the habitats are then prioritized for recovery actions.
The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve or other conservation area. It does not allow government or public access to private lands. A critical habitat designation does not impose restrictions on nonfederal lands unless federal funds, permits or activities are involved.
Fish and Wildlife officials will discuss the critical habitat proposal during a public meeting in Boise on Thursday, Feb. 25, from 4-6 p.m. The meeting will be held at the Boise Center on the Grove at 850 W. Front St. in downtown Boise. Officials will accept comments during a public hearing from 7-9 p.m.