Climate Change, Forests, Fire, Water, and Fish: a Synthesis for Land and Fire Managers
Climate Change, Forests, Fire, Water, and Fish: A Synthesis for Land and Fire Managers Charles H. Luce, Penelope Morgan, Kathleen A. Dwire, Daniel J. Isaak, Bruce E. Rieman, and Zachary Holden Introduction As the climate changes in the western United States streams are warming, low flows in summer are declining, and winter floods are occurring more often in places where snowmelt is the main source of water (Stewart et al., 2005; Hamlet and Lettenmaier, 2007a; Luce and Holden, 2009; Isaak et al., 2010). Some of the changes have been subtle, others more noticeable, and they are expected to shift distributions of fishes (Rieman et al., 2007; Wenger et al., 2011a; Wenger et al., 2011b). At the same time, the terrestrial ecosystems surrounding the mountain streams of the west are changing in response to the same climatic signals. Drier years and drier summers have often led to more large fires, many of which are more severe (Dillon et al., 2011). Further, fire regimes are shifting, with fires becoming more frequent in some places and less frequent in others, and potential conversion of forests to shrubs in some places (Pierce et al., 2004; Breshears et al., 2005; Westerling et al., 2006; Morgan et al., 2008; Westerling et al., 2011). Fires have long been prevalent in western mountain landscapes. Many, but not all, ecosystems benefit from the biomass consumption, cycling of nutrients, rejuvenation of vegetation, and changing vegetation composition and structure after fires (Agee, 1993). Indeed many species and ecological communities in the western U.S. depend on fire in some form. Some benefit from frequent fires that consume small amounts of fuel, while others, seemingly paradoxically, thrive as a result of infrequent but severe fires that consume most of the available fuel in their path.
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