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Lahontan Cutthroat ( clarkii henshawi)

Data: Lahontan Recovery Plan, 1995; A Business Plan for the Conservation of the : A 10-Year Plan for Conservation Through its Range, 2010; Lahontan Cutthroat Trout Status Update, 2009; Updated Goals and Objectives for the Con- servation of Lahontan Cutthroat Trout, 2019 Partners: The states of , , and , and the US and Wildlife Ser- vice, US Forest Service, US Bureau of Land Management, Pyramid Paiute Tribe, and Summit Lake Paiute Tribe

LAHONTAN CUTTHROAT TROUT CREDIT: JOSPHEH R. TOMELLERI © ii | Western Native Trout Status Report - Updated July 2020

Introduction from the East Carson drainage, which has been listed as threatened, and LCT from The Lahontan Cutthroat Trout (LCT; On- the Basin (Virgin-Thousand and corhynchus clarkii henshawi) evolved in the drainages), where the native cut- hydrographically isolated Lahontan Basin of throat trout form is extirpated. northeastern California, southeastern Oregon, These LCT forms developed several life history and northern Nevada (Figure 1) where ancient strategies and traits adapting to the diversity ebbed and flowed over millions of river, stream, and lake habitats with resident, of years. The LCT was listed as endangered by migratory, adfluvial and lacustrine character- the U.S. Fish and Wildlife Service on October istics. Lacustrine forms of LCT are uniquely 13, 1970 (35 FR 16047 16048), and down- adapted to persist in the desert terminal listed and reclassified as threatened (40 FR of the Lahontan Basin—they have an unusual 29863 29864) in 1975 to facilitate management tolerance for alkaline and saline waters. Some and allow regulated . The recovery plan forms have adapted to thrive in oligotrophic al- for LCT was approved in 1995. A status review pine lakes (e.g., and Independence in 2009 determined that LCT continues to Lake). For recovery purposes, the U.S. Fish and meet the definition of threatened. In 2019, the Wildlife Service and recovery partners orga- LCT Management Oversight Group (MOG) nized LCT forms into three Geographic approved updated goals and objectives for the Management Units (GMUs): Western (Truck- conservation of LCT (UGOs) that incorpo- ee, Carson, Walker and Susan ); Eastern rate recent science, improved knowledge, and (); and Northwestern (Quinn a widely accepted conservation framework to River/)(Figure 1). These guide efforts in conjunction with the existing recovery plan.

Historical and Current Distribution Recent work on the of cutthroat trout supports recognizing several unique evo- lutionary forms comprising the LCT lineage (Peacock et al. 2018). These forms include the Western Lahontan Basin (Truckee, Carson, Walker rivers, including Summit Lake); the Northwestern Lahontan Basin (); Eastern Lahontan Basin (Humboldt and Reese rivers); Coyote Lake Basin (Willow and Whitehorse rivers). There are two other forms Figure 1. Lahontan Cutthroat Trout histori- in the LCT lineage— cal distribution. LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | iii

GMUs have been further divided in the UGOs Lahontan Cutthroat Trout native to the into 10 smaller Management Units for conser- Western GMU are most imperiled; few extant vation implementation to meet specific recov- populations persist in these watersheds. In the ery objectives. basin, there are only two natu- rally reproducing stream populations and a In 1800, it is believed that more than 370,000 single naturally reproducing native lake popula- surface acres of lakes (in 12 larger lake systems) tion (Independence Lake). The and more than 7,400 miles of stream habitat has five remaining native fluvial populations, was occupied or had the potential to be oc- whereas the LCT population and cupied by LCT (USFWS 2009). After the all but one Walker basin fluvial population were mid-1800s, immigration and settlement within effectively extirpated by the late 20th century. the Lahontan Basin and Northern California All seven fluvial populations in the Walker resulted in impacts to LCT due to overharvest, Basin today are derived from one small extant mining, timber harvest, , water diver- population, By-Day Creek. The lacustrine sions, dams and reservoirs, and introduction population of Walker Lake was maintained by of non-native trout forms. By the mid-1900s, stocking of hatchery-reared LCT, but was fully LCT were extirpated from a majority of larger extirpated by 2009 due to reduced inflows and drainage basins and generally restricted to lower lake elevations and subsequent water isolated headwater, or small lake, systems. The chemistry changes. LCT has been extirpated from more than 90 percent of historical habitat (Dunham et al. The Western Lahontan Basin retains remnants 1997; Dunham et al. 2003). of Lahontan (Pyramid and Walker lakes). Although the three major river basins Currently, LCT have been documented to oc- that contain LCT in the Western Lahontan cur throughout its historical range except in the Basin (Carson, Walker, and Truckee rivers) Susan River drainage. About 70 self-sustaining were never inundated by the ancient pluvial LCT populations exist in about 10.5 percent lake, these streams originate in the eastern of the historical habitat (752 stream miles and and drain into these lacustrine 1,394 surface acres). Less than 10 percent of habitat remnants. The east and west forks of stream populations remain, mostly in small, join and flow into Walker Lake, isolated, headwater habitat fragments with low although this lake dried up and refilled mul- levels of genetic diversity (Peacock et al. 2018). tiple times in the past 11,000 years (Behnke These small stream populations may have lower 1992). abundances due to poor habitat quality and may not be resilient long term. Significant por- Lake Tahoe is the source for the Truckee River, tions of historical habitat are no longer suitable which flows into . Walker and trout habitat due to climatic and anthropogenic Pyramid are terminal lakes supporting highly factors. LCT currently occupy about 15 percent alkaline and nitrogen-limited . of the remaining potentially suitable habitat The stream drainages flowing into these lakes (LCT MOG 2019). There are also less than 30 historically provided spawning habitat and un- out-of-basin LCT populations. doubtedly formed networked ecosystems that iv | Western Native Trout Status Report - Updated July 2020

supported all life stages prior to water diver- hogany Creek and Snow Creek, which drain sions and introduction of non-native in into the lake, maintain a naturally reproducing the 20th century. LCT fishery. The majority of naturally sustaining fluvial The Coyote Lakes Basin, north of the Quinn LCT populations are found in the Humboldt River, in Oregon, contains Coyote Lake, a small River watershed. The Humboldt River is a large ephemeral lake, and the Willow and White- mainstem river that connected stream habitats horse stream systems. This basin was never con- prior to the European settlement of the Lahon- nected to the larger Lake Lahontan but may tan Basin. Historically, LCT populations were have connected to Lake Alvord during the Late interconnected at various temporal and spatial . Lake Alvord may have connected scales developing fluvial migratory life histories to Lake Lahontan earlier in the Pleistocene and metapopulation dynamics (Dunham et al (Reheis et al. 2002) giving LCT access to these 1997; Neville et al. 2006). two northern basins. The remaining native LCT are found only in streams of the Willow Although water still flows into the main stem and Whitehorse systems. Humboldt River from ancillary drainages, water diversions, poor habitat quality, and Habitat Requirements interspecific competition have largely isolated LCT within headwater reaches in either single Lahontan Cutthroat Trout are found in a streams or small groups of . Recent wide variety of cold-water habitats, including conservation efforts to reconnect tributaries large terminal alkaline lakes, alpine lakes, slow have been successful in some Humboldt sub- meandering rivers, mountain rivers, and small basins. headwater streams. They occur in cool Currently, 13 LCT populations occupy streams flowing water with available cover of well-veg- in the Quinn River drainage, and most of these etated and stable stream banks, in areas where habitats are isolated headwater reaches above there are stream velocity breaks, and in relative- barriers. Streams in the McDermitt Creek ly silt free, rocky riffle-run areas. However, they drainage remain interconnected, but non-native have demonstrated a tolerance for higher water salmonids threaten the integrity of this LCT temperatures for short periods of time. population network (Peacock and Kirchoff Historically, LCT were found in large inter- 2004). The Quinn River basin was inundated connected stream and/or stream and lake eco- by pluvial Lake Lahontan and in the post-lake systems. Demographic and genetic data reveal period, this system had as many as 46 streams a complex population dynamic for the few re- occupied by LCT (Coffin and Cowan 1995). maining interconnected stream systems (Ray et Summit Lake, north of the Black Rock Desert, al. 2000; Neville et al. 2006). Long-term occu- was formed by a landslide about 12,500 years pancy of these stream networks was historically ago and was subsequently isolated, along with achieved via movement of fish among discrete associated streams, from the rest of the western populations and re-colonization of extirpated basin drainages. Summit Lake, including Ma- habitat facilitated by interconnected waterways (Neville et al. 2006). LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | v

Lacustrine LCT populations have adapted 1983, Moyle 2002), whereas only 100–300 eggs to a wide variety of lake habitats, from small were found in females collected from small alpine lakes to large desert waters. Unlike most Nevada streams (Coffin 1981). Eggs are depos- , native lacustrine strains ited in small gravels within riffles or pool crests of LCT have adapted to alkalinity and total (USFWS 1995). Eggs generally hatch within dissolved solid levels as high as 3,000 mg/L 4–6 weeks, depending on water temperature, and 16,000 mg/L, respectively. This ability to and fry emerge 13–23 days later (Lea 1968, tolerate high alkalinity prompted introductions Moyle 2002). of LCT into saline-alkaline lakes in Nevada, Oregon, and for recreational Sportfishing purposes. LCT were reintroduced into Walker Lake, Nevada, where they were extirpated in Despite being listed as Threatened, LCT can the early 20th century due to water diversions, be harvested under a special 4(d) rule under the which prevented access to spawning habitat. Act that allows angling However, in the last several decades, over-allo- and harvest under state regulations. Conse- cated water rights and droughts have severely quently, LCT have played an important part of reduced inflow from the Walker River result- the in Nevada, California, ing in unnaturally high levels of alkalinity (> and Oregon for the past 40 years. They are 20,000 mg/L), and the lake no longer supports raised at state, tribal, and federal hatcher- fish life. Lahontan Cutthroat Trout of the his- ies for both recovery and recreational fishing toric Pilot Peak strain have been reintroduced purposes. There are also numerous other lakes into Pyramid Lake and the Lake Tahoe Basin. and streams in the historic drainages that are These native LCT are currently maintained by stocked with LCT from the Heenan Lake hatchery propagation along with significant broodstock established from Independence recent efforts to establish natural reproduction. Lake. In California, some high angler-use, out-of-basin waters are stocked (e.g., Crowley Reproduction Lake), and some wild, stream populations are managed with special regulations, typically Lahontan Cutthroat Trout inhabit lakes and zero-bag limits (e.g., and streams, but are obligatory stream - Wolf Creek). ers. Small, intermittent, tributary streams In Nevada, numerous LCT waters are open and headwater reaches are sometimes used as to fishing and are very popular, including the spawning sites (Coffin 1981, Trotter 1987). Truckee River and Pyramid Lake. To protect Spawning generally occurs from April through the integrity of fishable populations, special July, depending upon stream flow, eleva- fishing restrictions exist in some waters. Fish- tion, and water temperature (La Rivers 1962, able populations are also supported by hatch- McAfee 1966, Lea 1968, Moyle 2002). Fecun- ery stocking. The sportfish status of LCT and dity of 600–8,000 eggs per female has been increasing notoriety of successful fisheries like reported for lacustrine (lake dwelling) popu- Pyramid Lake has improved angler support for lations (Lea 1968, Cowan 1983, Sigler et al. LCT reintroduction and management. vi | Western Native Trout Status Report - Updated July 2020

Threats loss of many LCT populations. Additionally, Kokanee and are estab- The significant decline in range and numbers of lished in Lake Tahoe and . In LCT is primarily attributable to habitat frag- 2019, evidence of a recent invasion of Rainbow mentation and degradation and the introduc- Trout in Independence Lake was detected by tion of non-native trout throughout the species the discovery of some hybridized fish. This im- range along with dam and diversion structures portant wild lacustrine LCT population is now and water withdrawals in the Western GMU. in serious jeopardy, requiring extensive man- Other impacts include water diversion of rivers agement actions to prevent further damage. and streams as well as degradation of ripar- Fluvial LCT populations have been displaced ian habitat by poor domestic livestock grazing by competition and from introduced management. All of these threats represent sig- and , and from nificant impediments to recovery of naturally hybridization with . Non-native sustaining, networked populations. fish stocking for recreational fishing has been Habitat Degradation Concerns reduced or eliminated in areas important for recovery. In locations in which non-native fish Major impacts to LCT habitat include: 1) stocking is needed to maintain recreational reduction and alteration of stream discharge; 2) fisheries, fishery managers are using sterile trip- alteration of stream channels and morphology; loid Rainbow Trout and to mini- 3) degradation of water quality; and 4) reduc- mize the potential for hybridization with LCT. tion of lake levels and concentrated chemical components in natural lakes. Concentrations of Population Viability Concerns livestock in riparian areas causes habitat altera- Habitat loss and fragmentation have become tions of those areas, such as loss of undercut serious threats for species globally banks and other cover, exposed stream chan- (Green 2003, Reed 2004). Isolation and small nels, and increased silt loads, which lead to population size increase vulnerability to local wider and shallower streams that ultimately extirpation through demographic stochastic- causes elevated water temperatures during the ity in the short term, and genetic stochasticity summer, and colder temperatures during the in the long term (Lande 1998, Frankham and winter. Brook 2004, Munzbergova 2006). Loss of ge- Lacustrine habitat has been altered by con- netic variability through the process of random struction of dams and diversions, pollution, genetic drift can reduce the ability of natural reduced spawning flows, desiccation of lakes, populations to adaptively respond to changing and drought and water withdrawal. environmental conditions. In the case of wide- Non-native Fish Concerns ranging species, the aim is often to identify ge- netically distinct groups of populations whose Non-native Rainbow Trout, Brook Trout, and genetic differences reflect local adaptive dif- Brown Trout have become established in all ferences (Waples 1998, Solorzano et al. 2004, basins inhabited by LCT, contributing to the Ficetola and De Bernardi 2005). The genetic LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | vii

challenge to recovery of imperiled species is to prove the status of LCT include: preserve enough variation to facilitate adap- • Fish population analyses and manipu- tive responses to changing environments and lations (genetic evaluations, extensive maintain evolutionary potential. population surveys, fish translocations Climate Change and fish stockings); Climate change will pose additional threats to • Watershed management planning; inland cutthroat trout due to their narrow tem- • Habitat analyses and manipulations perature tolerance and specific habitat needs (habitat inventory, habitat improvement (Rieman et al. 2007, Williams et al. 2009). activities, changes in grazing practices, Lahontan Cutthroat Trout may be particularly and riparian fencing and enclosures); vulnerable given the high variability in flow and temperature within their range (Platts and • Land exchanges and acquisitions to Nelson 1988, Galbraith and Price 2009). Tem- secure important LCT habitat; perature increases will likely restrict LCT from • Development of fishery management lower elevation habitats and push them higher plans and appropriate fishing regula- into headwater streams, further compounding tions and angling closures; and the impact of fragmentation (Rahel et al. 1996). Populations will also be at increased risk from • Reduction or elimination of stocking fire (Westerling et al. 2006), flooding, drought of non-native trout in recovery waters, (Mote et al. 2003), and invasions of non-native and stocking LCT instead of non-native species and disease pathogens that can express fish. enhanced resilience to increased temperatures. LCT Population Surveys, genetic analyses, Dramatic burns and severe drought are increas- ing, directly impacting several LCT popula- and fish population manipulation tions. Increased wildfire frequency and intensity Key actions will include: diminishes the capacity of habitats, making it unlikely to sustain the long-term persistence • Maintain genetic diversity of extant and viability of many remaining populations LCT populations by securing existing (Wenger et al. 2017). populations and expanding occupied habitat; • Conduct standardized population sur- Conservation veys and implement a genetic monitor- Ongoing and future conservation for LCT is ing program to assess the effectiveness focused on the conservation biology principles of habitat improvement projects on of Representation, Redundancy, and Resil- population size and maintenance of iency (3 R’s), which form the framework of the genetic diversity; recently completed UGOs. • Reduce impacts of non-native - Conservation measures implemented to im- nids by reducing or eliminating repro- viii | Western Native Trout Status Report - Updated July 2020

ducing populations of these species. improving instream and riparian conditions, Conduct non-native trout suppression addressing land use practices conditions, and efforts in selected waters where prior- restoring limited stream fragments. ity LCT populations are at-risk. Stop Key actions will include: artificial stocking of non-native fishes in LCT recovery waters; and • Secure and improve riparian and in- stream habitat for the restoration of • Review and update fishery management LCT fluvial populations; and production plans on a prescribed schedule to incorporate current science. • Identify critical stream and riparian Development of Watershed-based Fishery zone habitats for cooperative manage- ment projects and recovery of LCT; Management Plans • Restore and enhance water flow, includ- Key actions will include: ing restoring the natural hydrograph, not necessarily historic volumes, in key • Develop cooperative management plans habitats; to manage major watersheds focusing on reducing degradation of riparian, • Address public and private land man- stream, and lake ecosystems leading to agement practices to improve watershed improved water temperature profiles habitats for LCT and reduce livestock and manage for LCT for recreational and agricultural impacts; fishing; • Monitor and evaluate natural catastro- • Develop cooperative management phe impacts like fire and drought; and plans to remove movement barriers and • Investigate opportunities to locate, de- provide fish passage to interconnected sign, and construct bar- habitats; and riers that will exclude non-native trout • Assess the impact of climatic changes and help create new connected habitats and drought or other catastrophic following non-native trout eradication events, such as wildfires, on the recovery projects. of LCT. LCT Habitat Manipulations Lahontan Cutthroat Management related to pub- lic use and supplemental stocking Restoration of LCT habitat must address habitat and water quality and quantity issues. Key actions will include: Restoration of a natural hydrograph, in - sonal variation, if not in historic volume, is key • Revise current management plans to to the restoration and maintenance of riparian clarify the role of hatchery-produced habitat and channel function. Current efforts fish conservation and recreational fish- to manage LCT have been directed toward ing; LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | ix

• Evaluate the use of broodstock eggs to detected and removed when encoun- establish self-sustaining populations tered at the lake, or inlet stream, during of LCT in the Western GMU if wild spawning trap operations. Continue LCT are not available. LCT strains na- to operate other ongoing non-native tive to each GMU basin should be used removal efforts, and conduct genetic for basin-specific recovery activities; and analyses to support identification and removal. • Manage sportfishing to preclude adverse angling impacts on LCT through the • Support continuing efforts to maintain use of special fishing regulations and use and enhance Summit Lake LCT popu- of LCT for recreational fishing in place lation resiliency to support long-term of non-natives. persistence. Highest Priority Actions for LCT by major • Support efforts to achieve funding from watershed (Figure 2) the Lake Tahoe Restoration Act to help with priority LCT conservation in the 1) Western Lahontan Basin (Truckee, Carson, Tahoe Basin including: non-native trout and Walker River sub-basins) suppression and removal in the Upper Prevent further losses of genetic variation of Truckee River and Fallen Leaf Lake; extant populations and suitable habitat, and habitat improvements; and expanded restore historically occupied habitat. production of hatchery LCT to increase • Use the Pilot Peak strain LCT for LCT LCT angling opportunities in the basin. restoration in the Pyramid-Truckee- • Engage stakeholders and the public to Tahoe corrido because it is the most increase awareness and support for LCT suitable strain adapted for these termi- restoration. nal lake and interconnected habitats. • Establish a new hatchery rearing pro- Seek to establish a naturally reproduc- gram for Walker River Basin strain of ing population in the Truckee River by LCT at CDFW’s Hot Creek Hatchery. implementing fish passage improvement Build public support for LCT restora- projects and efforts to minimize hybrid- tion by increasing angling opportunities ization with Rainbow Trout. Continue and positive experiences with hatchery to supplement Pyramid and Tahoe Walker LCT produced for recreation. Basin fisheries with hatchery-produced Operate under conservation hatchery Pilot Peak fish. breeding protocols so that LCT may • Implement management actions to be used to support restoration efforts, if prevent and reduce further hybridiza- needed. Investigate lacustrine life his- tion of the Independence Lake LCT tory traits expression of Walker LCT by population. Tag as many individual fish stocking fish produced in differing lake as possible, and collect genetic samples habitats. for each fish so that hybrid fish can be x | Western Native Trout Status Report - Updated July 2020

Figure 2. Lahontan Cutthroat Trout watersheds. 2) Northwestern Lahontan Basin (Quinn 3) Eastern Lahontan Basin (Humboldt and River, Black Rock Desert, and Coyote Lake Reese Rivers) sub-basins) • Prevent further losses of genetic varia- • Prevent further losses of genetic varia- tion of extant populations and suitable tion of extant populations and suitable habitats. habitats. • Maintain existing and establish new • Support efforts to acquire the Disaster connected metapopulations in five Peak Ranch by Western Rivers Conser- Humboldt GMU sub-basins (described vancy so that habitats in the McDermitt in UGOs). Complete efforts to remove Creek system can be secured and efforts non-natives and develop large inter- to restore a resilient meta-population connected habitats in the North Fork system in the GMU can be achieved. Humboldt River. Implement actions to • Continue to monitor population and remove non-natives and establish con- genetic status of LCT in the GMU nected population in the upper Reese along with habitat assessments and River tributaries. improvements. • Develop and implement plans to ad- LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | xi

dress hybridization issues in Marys • 2008 - Maggie Creek fish migration River sub-basin. barrier to protect a Lahontan Cutthroat Trout population in the Maggie Creek • Develop a process to strategically en- Subbasin (NV) gage local stakeholders to help recovery partners collaboratively develop and im- plement unit-based conservation action Literature plans. Develop a “template for success” with stakeholders in the South Fork Behnke R. J. 1992. Native Trout of Western Humboldt sub-basin (pilot project) that . American Fisheries Society, can be used to build partnerships with Bethesda. stakeholders in other parts of the LCT Coffin, P. D., and W. F. Cowan. 1995. Lahon- range. Initiate a multi-step, multi-year tan cutthroat trout (Oncorhynchus clarki hen- process that results in a Collaborative shawi) recovery plan. U. S. Fish and Wildlife Conservation Action Plan. Service, Region I, Portland, Oregon. WNTI Completed/Ongoing Dunham J. B., K. A Young., R. E. Gresswell and B. E. Rieman. 2003. Effects of fire on fish Projects populations: landscape perspectives on persis- tence of native fishes and nonnative fish inva- • 2017 - TROUT at WHCCD (Trans- sions. Forest Ecology Management 178: 183–196. forming Research Opportunities for Undergraduate Training at West Hills Dunham, J. B., G. L. Vinyard, and B. E. Rie- Community College District) (CA) man. 1997. Habitat fragmentation and extinc- tion risk of Lahontan Cutthroat Trout. North • 2016 - Lahontan Cutthroat Trout Re- American Journal of Fisheries Management covery Interpretive Panel (CA) 17:1126-1133. • 2016 - Exploration Lahontan Cutthroat Ficetola, G. F. and F. De Bernardi. 2005. Trout (LCT) Camp (NV) Supplementation or in situ conservation? • 2009 - McDermitt Creek Fish Migra- Evidence of local adaptation in the Italian agile tion Barrier to Protect a Lahontan Cut- frog Rana latastei and consequences for the throat Trout population (NV) management of populations. Conserva- tion 8: 33-40 Part 1. • 2009 - Susie Creek Fish Barrier to Pro- tect High Priority Recovery Habitat for Frankham, R. and B. W. Brook. 2004. The im- Lahontan Cutthroat Trout in Humboldt portance of time scale in conservation biology County (NV) and ecology. Annales Zoologici Fennici 41 (3): 459-463. • 2008 - Lower McDermitt Creek Fish Barrier to Protect Lahontan Cutthroat Galbraith, H., and J. Price. 2009. A framework Metapopulation (NV) for categorizing the relative vulnerability of threatened and endangered species to climate xii | Western Native Trout Status Report - Updated July 2020

change. Page 113. U.S. Environmental Protec- Platts, W. S., and R. L. Nelson. 1988. Fluctua- tion Agency (EPA), Washington, D.C. tions in trout populations and their implica- tions for land-use evaluation. North American Green, D. M. 2003. The ecology of extinction: Journal of Fisheries Management 8:333-345. population fluctuation and decline in amphib- ians. Biological Conservation 111: 331-343. Rahel, F. J., C. J. Keleher, and J. L. Anderson. 1996. Potential habitat loss and population Hanski, I. 1999. Metapopulation ecology. Ox- fragmentation for cold water fish in the North ford University Press, Oxford, England. drainage of the : Hanski, I., and M. E. Gilpin. 1997. Metapopu- response to climate warming. Limnology and lation biology: ecology, and evolution. Oceanography 41:1116-1123. Academic Press, San Diego, California. Reed, D. H. 2004. Extinction risk in fragment- Lande, R. 1998. Anthropogenic, ecological and ed habitats. Animal Conservation 7: 181-191 genetic factors in extinction and conservation. Part 2. Researches on Population Ecology 40 (3): 259-69. Rieman, B. E., D. Isaak, S. Adams, D. Horan, Mote, P. W., E. A. Parson, A. F. Hamlet, W. D. Nagel, C. Luce, and D. Myers. 2007. An- S. Keeton, D. Lettenmaier, N. Mantua, E. ticipated climate warming effects on L. Miles, D. W. Peterson, D. L. Peterson, R. habitats and populations across the Interior Slaughter, and A. K. Snover. 2003. Preparing basin. Transactions of the for climate change: the ater, salmon, and forests American Fisheries Society 136:1552-1565. of the . Climatic Change Solorzano, S., A. J. Baker, and K. Oyama. 61:45–88. 2004. Conservation priorities for Resplendent Munzbergova Z. 2006. Effect of population Quetzals based on analysis of mitochondrial size on the prospect of species survival. Folia DNA controlregion sequences. Condor 106 (3): Geobotanica 41 (2): 137-150. 449-456. National Fish and Wildlife Foundation. 2010. Waples, R. S. 1998. Evolutionarily significant A Business Plan for the Lahontan Cutthroat units, distinct population segments, and the Trout. 22pp. endangered species act: Reply to Pennock and Neville, H. M., J. B. Dunham, and M. M. Dimmick. Conservation Biology 12 (3): 718- Peacock. 2006. Landscape attributes and life 721. history variability shape genetic structure of Wenger, S.J., D.R. Leasure, D.C. Dauwalter, trout populations in a stream network. Land- M.M. Peacock, J.B. Dunham, N.D. Chelgren, scape Ecology 21:901-916. and H.M. Neville. 2017. Viability analysis for Peacock, M. M. and V. S. Kirchoff. 2004. As- multiple populations. Biological Conservation sessing the conservation value of hybridized 216:69-77. cutthroat trout populations. Transactions of the Westerling, A. L., H. G. Hidalgo, D. R. Cayan, American Fisheries Society 133:309-325. and T. W. Swetnam. 2006. Warming and earlier spring increase western U.S. forest wildfire LAHONTAN CUTTHROAT TROUT (Oncorhynchus clarkii henshawi) | xiii

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This publication was funded (or partially funded) by Federal Aid to Sportfish Restora- tion Funds through the Multistate Conser- vation Grant Program (Grant WY M-8-P), a program supported with funds from the Wildlife and Sport Fish Restoration Program of the U.S. Fish and Wildlife Service and jointly managed with the Association of Fish and Wildlife Agencies, 2006-9.