The potential influence of changing climate on the persistence of salmonids of the inland west

Abstract

Cover. Westslope cutthroat trout (top) and Bonneville cutthroat trout (bottom). Photo courtesy of Kirk Dahle and Mike Ebinger.

Estimating Thermal Regimes of Bull Trout and Assessing the Potential Effects of Climate Warming on Critical Habitats

“…This is particularly true for salmonid species (e.g. trout, char, and salmon) that are strongly influenced by changes in temperature, flow, and physical habitat conditions (Haak et al ., ). Salmonids are especially vulnerable to climate‐induced warming in freshwater ecosystems because of the following: (i) they have ectothermic physiologies; (ii) they require streams and lakes with cold, high‐quality habitats, which are easily fragmented by thermal or structural barriers; (iii) their distributions and abundances are strongly influenced by temperature and stream flow gradients; and (iv) they have narrow tolerances to thermal fluctuations in cold waters (Dunham et al ., ; McCullough et al ., ; Williams et al ., ; Isaak et al ., ).…”

The Past as Prelude to the Future for Understanding 21st‐Century Climate Effects on Rocky Mountain Trout

“…Physiological requirements of these fishes for cold temperatures, combined with historic population declines from a century of intensive land use and development, have raised concerns regarding how climate change may affect their future status across the region. Several recent reviews described a range of potential climate effects (Independent Science Advisory Board 2007; Rahel et al 2008;Haak et al 2010;Rieman and Isaak 2010), but the general conclusions are that stream habitats will become warmer, more variable with regards to thermal and hydrologic conditions, and prone to larger, more frequent disturbances that are significantly different from historical conditions (Jentsch et al 2007). Fish populations, in response, are predicted to adapt in place through phenotypic or genotypic means, move to track suitable habitats, or be extirpated (Crozier et al 2008;McCullough et al 2009).…”

Point‐Counterpoint: Be Flexible in the Number of Talks per Speaker at Meetings!

“…Stream flows in these locations tend to be steady and moderate over winter, which provide safe conditions for the incubation of the eggs of fall-spawning trout species such as Bull Trout Salvelinus confluentus. However, as climate warms, rainstorms in a snowy landscape can melt snow and lead to increasing winter floods (Graybeal and Leathers 2006;Haak et al 2010), which may be particularly detrimental to fall-spawning of Bull Trout and Brook Trout S. fontinalis. Winter floods can scour stream beds and drastically increase erosion.…”

“…In 2009, TU and the U.S. Forest Service initiated a project to reconstruct the historic Crow Creek channel and restore the natural hydrologic processes that had been interrupted when the channel was straightened. The goal of the project was to restore channel function, increase available instream habitat, and improve water quality to buffer Salt River YCT populations from catastrophic environmental events like floods, fires, and droughts that are predicted to increase in the region (Haak et al 2010). Intact stream channels and vegetated floodplains mitigate the effects of those events by attenuating flood flows, storing and slowly releasing ground water back to streams during low flows, and providing lush riparian vegetation that resists fire and filters sediment and ash during run-off events.…”

“…Climate change is rapidly becoming one of the most challenging issues for management of trout, salmon, and other coldwater fisheries. Climate-induced changes in flows and disturbance regimes (Stewart et al 2005;Haak et al 2010) will confound stream restoration efforts as rising temperatures and other stressors reduce suitable coldwater fish habitat (Kaushal et al 2010). Despite the added complexity and uncertainty, stream managers have begun to integrate climate change adaptation into restoration and monitoring efforts.…”