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Hudec et al. Front Matter 1 1 Climate Change Vulnerability and Adaptation in 2 Southwest Washington 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Editors 33 J.L. Hudec is an ecologist, U.S. Department of Agriculture, Forest Service, Gifford Pinchot 34 National Forest, Mt. Adams Ranger District, 2455 Hwy 141, Trout Lake, WA 98650; J.E. 35 Halofsky is a research ecologist, University of Washington, College of the Environment, School 36 of Environmental and Forest Sciences, Box 352100, Seattle, WA 98195-2100; D.L. Peterson is 37 a senior research biological scientist, U.S. Department of Agriculture, Forest Service, Pacific 38 Northwest Research Station, 400 N 34th St., Suite 201, Seattle, WA 98103; J.J. Ho is a research 39 economist, University of Washington, College of the Environment, School of Environmental and 40 Forest Sciences,DRAFT Box 352100, Seattle, WA 98195-2100. Hudec et al. Front Matter 2 41 Climate Change Vulnerability and Adaptation in 42 Southwest Washington 43 44 J.L. Hudec, J.E. Halofsky, D.L. Peterson, and J.J. Ho 45 46 47 Editors 48 49 50 51 52 53 U.S. Department of Agriculture, Forest Service 54 Pacific Northwest Research Station 55 Portland, Oregon 56 General Technical Report PNW-GTR-xxxx 57 Month year 58 DRAFT Hudec et al. Front Matter 3 59 Abstract 60 61 Hudec, J.L.; Halofsky, J.E.; Peterson, D.L.; Ho, J.J., eds. 201X. Climate change vulnerability 62 and adaptation in Southwest Washington. Gen. Tech. Rep. PNW-GTR-xxx. Portland, OR: 63 U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. Xxx p. 64 65 The Southwest Washington Adaptation Partnership (SWAP) was developed to identify climate 66 change issues relevant for resource management in Southwest Washington, specifically on 67 Gifford Pinchot National Forest. This science-management partnership assessed the vulnerability 68 of natural resources to climate change, and developed adaptation options that minimize negative 69 impacts of climate change on resources of concern and facilitate transition of diverse ecosystems 70 to a warmer climate. The vulnerability assessment focuses on fish and aquatic habitat, 71 vegetation, special habitats, recreation, and ecosystem services. 72 Projected changes in climate and hydrology will have far-reaching effects on aquatic and 73 terrestrial ecosystems, especially as frequency of extreme climatic events (drought, low 74 snowpack) and ecological disturbances (flooding, wildfire, insect outbreaks) increases. 75 Distribution and abundance of cold-water fish species are expected to decrease in response to 76 higher water temperature, although effects will vary as a function of local habitat and 77 competition with nonnative fish. 78 Higher air temperature, through its influence on soil moisture, is expected to cause 79 gradual changes in the distribution and abundance of plant species, with drought-tolerant species 80 becoming more dominant. Increased frequency and extent of wildfire will facilitate vegetation 81 change, in some cases leading to altered structure and function of ecosystems (e.g., more forest 82 area in younger age classes). Special habitats such as riparian areas and wetlands are expected to 83 be especially sensitive to altered soil moisture, especially as drought frequency increases. 84 The effects of climate change on recreation activities are difficult to project, although 85 warmer temperatures are expected to create more opportunities for warm-weather activities (e.g., 86 hiking, camping) and fewer opportunities for snow-based activities (e.g., skiing, snowmobiling). 87 Recreationists modify their activities according to current conditions, but recreation management 88 by federal agencies has generally not been so flexible. 89 Of the ecosystem services considered in the assessment, timber supply and carbon 90 sequestration may be affected by increasing frequency and extent of disturbances. Native 91 pollinators may be affected by altered vegetation distribution and phenological mismatches 92 between insects and plants. 93 Resource managers convened at a SWAP workshop and developed adaptation options in 94 response to the vulnerabilities identified in each resource area, including both high-level 95 strategies and on-the-ground tactics. Many adaptation options are intended to increase the 96 resilience of aquatic and terrestrial ecosystems, or to reduce the effects of existing stressors (e.g., 97 removal of nonnative species). In terrestrial systems, a dominant theme of adaptation in 98 Southwest Washington is to accelerate restoration and fuel treatments, particularly in drier forest 99 types, to reduce the undesirable effects of extreme events and high-severity disturbances 100 (wildfire, insects). In aquatic systems, a dominant theme is to restore the structure and function 101 of streams to retain cold water for fish and other aquatic organisms. Many adaptation options can 102 accomplish multiple outcomes; for example, fuel treatments in dry forests reduce fire intensity, 103 which in turn reduces erosion that would degrade water quality and fish habitat. Furthermore, 104 many existingDRAFT management practices are already “climate-informed” or require minor adjustment Hudec et al. Front Matter 4 105 to make them so. Long-term monitoring is needed to detect climate change effects on natural 106 resources of concern and to evaluate the effectiveness of adaptation options that are 107 implemented. 108 109 Keywords: Adaptation, aquatic ecosystems, climate change, fire, climate-informed 110 management, ecosystem services, fisheries, recreation, science-management partnership, 111 Southwest Washington, terrestrial ecosystems, vegetation. 112 113 114 DRAFT Hudec et al. Front Matter 5 115 Summary 116 117 The Southwest Washington Adaptation Partnership (SWAP) is a science-management 118 partnership consisting of Gifford Pinchot National Forest, the U.S. Forest Service Pacific 119 Northwest Region and Pacific Northwest Research Station, and the University of Washington. 120 These organizations worked together over a period of two years to identify climate change issues 121 relevant to resource management in Southwest Washington and to find solutions that can 122 minimize undesirable effects of climate change and facilitate transition of diverse ecosystems to 123 a warmer climate. SWAP provided education, conducted a climate change vulnerability 124 assessment, and developed adaptation options for Gifford Pinchot National Forest and adjacent 125 landowners. 126 Global climate models for a high-end greenhouse gas emission scenario (RCP 8.5; 127 comparable to current emissions) project that climatic warming will continue throughout the 21st 128 century. Compared to observed historical temperature (1950-1979), average warming is 129 projected to increase from 1.3 to 2.3 °C from 2010 to 2039, 2.5 to 4.2 °C for 2040-2069, and 4.3 130 to 6.4 °C for 2070-2099. Seasonally, the largest increases in temperature are projected for 131 summer (+5.7-6.8 °C on average for June–August in 2070-2099). Mean summer precipitation is 132 projected to decrease from 162 mm historically to 87-21 mm by the end of the century, while 133 extreme precipitation events are likely to increase. 134 Projected changes in climate and hydrology will have far-reaching effects on aquatic and 135 terrestrial ecosystems, especially as frequency of extreme climatic events (drought, low 136 snowpack) and associated effects on ecological disturbance (flooding, wildfire, insect outbreaks) 137 increase. Vulnerability assessment and development of adaptation options for Southwest 138 Washington conclude the following: 139 140 Fisheries and aquatic habitat— 141 • Effects: Higher winter streamflows, decreased summer streamflows, and warmer water 142 temperature will reduce habitat quality and extent for cold-water-dependent fish species. 143 Anadromous fish species will be susceptible to higher thermal stress during summer 144 upstream migrations, reduced access to upstream spawning areas, increased pre-spawn 145 mortality rates or reduced viability of eggs and embryos, and harsher conditions due to 146 greater disturbances while juveniles rear in streams or migrate downstream. Based on 147 projected stream temperatures in a warmer climate, coho salmon, which currently access 584 148 km of streams and rivers, may lose 40-65 percent of their current habitat. Chinook salmon 149 occupy a more restricted area (approximately 359 km) within the same river systems as coho, 150 and are susceptible to the same amount of habitat loss. Steelhead occupy the largest extent 151 (900 km of streams) of the anadromous fish species. Bull trout, which require very cold 152 water, live in fragmented habitats and have relatively small populations. In addition to 153 aforementioned stressors, bull trout will be increasingly susceptible to competition with 154 brook trout and other nonnative species in a warmer climate. 155 • Adaptation options: Primary adaptation strategies for fisheries and aquatic habitat focus on 156 storing more water on the landscape, increasing resilience to disturbance, maintaining and 157 restoring riparian and wetland vegetation complexity, and maintaining and restoring natural 158 thermal conditions in streams. Strategies in response to increased peak streamflows include 159 increasing spawning habitat resilience by restoring stream structure and processes and by 160 reducingDRAFT threats from roads and infrastructure, particularly in floodplains. A key strategy to Hudec et