Feasibility Assessment for the Reintroduction of Fishers in Western Oregon, USA

Home , Elliott State Forest, Western Cascades

Prepared by

Tim L. Hiller

March 2015

Feasibility assessment for reintroduction of fishers in western Oregon, USA 2

This report completed in partial fulfillment of U.S. Fish and Wildlife Service Cooperative Agreement Award F14AC00861.

Suggested citation:

Hiller, T. L. 2015. Feasibility assessment for the reintroduction of fishers in western Oregon, USA. U.S. Fish and Wildlife Service, Portland, Oregon, USA.

Cover figure courtesy of Oregon Department of Wildlife (Oregon State Game Commission, Game Division, 1962 annual report).

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TABLE OF CONTENTS

ACKNOWLEDGMENTS ...... 4 OBJECTIVES OF THIS ASSESSMENT ...... 6 LIST OF TABLES ...... 8 LIST OF FIGURES ...... 9 INTRODUCTION ...... 11 HABITAT AVAILABILITY...... 12 Coarse-scale Habitat Availability ...... 13 Fine-scale Habitat Assessment ...... 14 PREY BASE ...... 16 INTERSPECIFIC EFFECTS ...... 18 Interspecific Killing of Fishers ...... 18 Potential Effects on Species of Concern ...... 21 POTENTIAL SOURCE POPULATIONS ...... 26 POTENTIAL REINTRODUCTION THREATS ...... 29 Land Management Decisions ...... 29 Climate Change and Wildfires ...... 37 Vehicle collisions ...... 38 Incidental Harvest ...... 39 Anticoagulant Rodenticides ...... 40 Risks of Small Populations ...... 41 Pathogens and Parasites ...... 42 LEGAL AND REGULATORY REQUIREMENTS ...... 43 State...... 43 Federal...... 43 NECESSARY ELEMENTS ...... 45 POTENTIAL STAKEHOLDERS AND COOPERATORS ...... 48 CONCLUSIONS AND RECOMMENDATIONS ...... 48 LITERATURE CITED ...... 51

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ACKNOWLEDGMENTS

Many individuals from various agencies and organizations provided assistance and expertise to help complete this assessment. Special thanks to Sue Livingston for drafting the Federal Regulations section, reviewing several drafts of the document, and assisting with several other aspects of the assessment; Steve Niemela for drafting the State Regulations section; Craig Thompson for drafting the section on anticoagulant rodenticides; Greta Wengert for drafting the section on interspecific killing of fishers; and Larry Reigel (U.S. Fish and Wildlife Service) for GIS support. Jeff Lewis provided background information, numerous helpful suggestions, and reviewed an initial draft of the assessment. Finally, thanks to all of the reviewers, as their efforts improved the quality and accuracy of this assessment. Inclusion of the names of contributors and reviewers does not necessarily imply endorsement of the contents of this assessment. The U.S. Fish and Wildlife Service provided funding to produce this document.

Dr. Tim L. Hiller Forest and Wildlife Research Center Mississippi State University Mississippi State, Mississippi Email: [email protected]

List of Contributors

Sue Livingston U.S. Department of the Interior Fish and Wildlife Service Oregon Fish and Wildlife Office Portland, Oregon

Steve Niemela Rogue Watershed District Oregon Department of Fish and Wildlife Central Point, Oregon

Dr. Craig Thompson U.S. Department of Agriculture Forest Service Pacific Southwest Research Station Fresno, California

Dr. Greta Wengert Integral Ecology Research Center Blue Lake, California

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List of Reviewers (accepted invitation to review and returned comments)

Dr. Keith Aubry Sue Livingston U.S. Department of Agriculture U.S. Department of the Interior Forest Service Fish and Wildlife Service Pacific Northwest Research Station Oregon Fish and Wildlife Office Olympia, Washington Portland, Oregon

Josh Chapman Jamie E. McFadden-Hiller U.S. Department of Agriculture Forest and Wildlife Research Center Forest Service Mississippi State University Pacific Northwest Region Mississippi State, Mississippi Portland, Oregon

John Chatel Sean Mohren U.S. Department of Agriculture National Park Service Forest Service Crater Lake National Park Region 6, Threatened and Endangered Crater Lake, Oregon Species Program Portland, Oregon

Joe Doerr Steve Niemela U.S. Department of Agriculture Rogue Watershed District Forest Service Oregon Department of Fish and Wildlife Willamette National Forest Central Point, Oregon Springfield, Oregon

Dr. Dwayne Etter Michael Rochelle Wildlife Division Weyerhaeuser Company Michigan Department of Natural Resources Lebanon, Oregon East Lansing, Michigan

Bruce Hollen Dave Vesely U.S. Department of Interior Oregon Wildlife Institute Bureau of Land Management Corvallis, Oregon Oregon/Washington State Office Portland, Oregon

Dr. Jeff Lewis Washington Department of Fish and Wildlife Olympia, Washington

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OBJECTIVES OF THIS ASSESSMENT

The objective of this feasibility assessment is to review and evaluate available information on factors that could affect the success of a fisher reintroduction in western Oregon. The assessment area coincides with the Oregon portion of the proposed West Coast Distinct Population Segment (DPS) delineated by the U.S. Fish and Wildlife Service for the proposed listing of fishers under the federal Endangered Species Act (federal ESA; U.S. Fish and Wildlife Service 2014a,b). It includes all or portions of Benton, Clackamas, Clatsop, Columbia, Coos, Curry, Deschutes, Douglas, Hood River, Jackson, Jefferson, Josephine, Klamath, Lane, Lincoln, Linn, Marion, Multnomah, Polk, Tillamook, Wasco, Washington, and Yamhill counties (Fig. 1). Information about fishers in Oregon was given the highest priority in this assessment, but to fill in various knowledge gaps, it was necessary to also use information from California, Washington, and other areas. A reintroduction (a type of translocation) is, “…an attempt to reestablish a population where one no longer exists within a species’ historical range” (Lewis et al. 2012:2). Consequently, this assessment does not consider the potential consequences of augmenting either of the two extant populations of fishers in southwestern Oregon.

A reintroduction of fishers in Oregon would be considered successful in the short term if it resulted in a viable population in the release area(s); it would be successful in the long term if it resulted in population persistence with the opportunity for connectivity with adjacent populations. Beyond assessing whether reintroduction of fishers in western Oregon is feasible, a formal feasibility assessment can have benefits such as increasing public awareness and garnering support of stakeholders, providing the foundation for an implementation plan, and initiating planning efforts for a complex reintroduction project that involves coordination among multiple government agencies and other groups (Berg 1982, Lewis et al. 2012). Although the audience targeted for this assessment is designed to be natural resource managers, other groups and individuals will also undoubtedly have interest in participating in fisher reintroduction efforts.

Topics in this reintroduction feasibility assessment specific to western Oregon include to:

1. Describe the availability and configuration of fisher habitat and determine if one or more areas can support a population,

2. Describe the fisher prey base expected to occur based on habitat characteristics,

3. Assess potential interspecific interactions and effects (e.g., fisher predators, other furbearers, effects of fishers on species of concern),

4. Identify potential source populations (considering suitable genetics and effects of removal on the founder population),

5. Assess existing threats that may affect reintroduction success,

6. Identify and describe legal and regulatory requirements of a reintroduction, Feasibility assessment for reintroduction of fishers in western Oregon, USA 7

7. Identify and describe elements needed to implement a reintroduction program, including long-term support and monitoring after release, and

8. Identify potential stakeholders and cooperators.

This assessment is organized based on these topics, many of which follow the Guidelines for Reintroductions and Other Conservation Translocations, published by the International Union for Conservation of Nature (2014). The conclusions and recommendations have been developed using the best available supporting evidence from scientific publications, white papers, historical documentation, government information, and other sources.

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LIST OF TABLES

Table 2. Estimated amount of high-quality habitat for fishers in western Oregon, USA, based on U.S. Fish and Wildlife Service (2014c).

Table 3. Regional comparison for potential reintroduction of fishers in western Oregon, USA. Feasibility assessment for reintroduction of fishers in western Oregon, USA 9

LIST OF FIGURES

Fig. 1. Area of interest for fisher reintroduction feasibility assessment includes counties shown (excluding Lake and Sherman counties) in western Oregon, USA. Shaded area represents the proposed West Coast Distinct Population Segment boundary (U.S. Fish and Wildlife Service 2014a). Figure courtesy of U.S. Fish and Wildlife Service.

Fig. 2. Indigenous and reintroduced fisher populations in California, Oregon, and Washington, USA. NCSO = northern CA-southwestern OR, NSN = northern Sierra Nevada, ONP = Olympic Peninsula, SSN = southern Sierra Nevada. Figure courtesy of U.S. Fish and Wildlife Service.

Fig. 3. Proposed West Coast Distinct Population Segment of fisher, including pre- and post- 1993 fisher detections. Recent data from Olympic Peninsula reintroduction efforts in Washington were not available at the time of this assessment. Figure courtesy of U.S. Fish and Wildlife Service. Detections with high reliability described in U.S. Fish and Wildlife Service (2014c:28–29).

Fig. 4. Amount (%) of canopy cover of all live trees in A) western Oregon, USA (county boundaries shown in black), and B) U.S. Forest Service National Forests (boundaries shown in red), based on data from LEMMA (2012).

Fig. 5. Distribution of elevation ranges within A) U.S. Forest Service lands (boundaries shown in red), B) spatial description and labeled U.S. Forest Service lands, and distribution of elevation ranges within C) western Oregon, USA (county boundaries shown in black). Dark gray = 0– 1,000 m (0–3,300 ft), light gray (limited to area east of approximate crest of Cascade Range) = 1,000–2,200 m (3,300–7,200 ft).

Fig. 6. Estimates of habitat quality for fishers based on models developed by the U.S. Fish and Wildlife Service (2014c; Fitzgerald et al. 2014), western Oregon, USA. Light black lines represent county boundaries and bold black line represents proposed West Coast Distinct Population Segment boundary in Oregon. Figure courtesy of U.S. Fish and Wildlife Service.

Fig. 7. Distribution of land ownership in western Oregon, USA. Light black lines represent county boundaries and bold black line represents proposed West Coast Distinct Population Segment boundary in Oregon. Figure courtesy of U.S. Fish and Wildlife Service.

Fig. 8. Lands under federal management with estimated high-quality habitat for fishers based on models developed by the U.S. Fish and Wildlife Service (2014c), western Oregon, USA. Bold black line represents proposed West Coast Distinct Population Segment boundary in Oregon.

Fig. 9. Amount (%) of cover of down wood ≥25 cm (9.8 in) in diameter at large end and ≥3 m (9.8 ft) long in A) western Oregon, USA, (county boundaries shown in black) and B) U.S. Forest Service National Forests (boundaries shown in red), based on data from LEMMA (2012).

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Fig. 10. Density of snags, defined as number of trees ≥25 cm (9.8 in) diameter-at-breast height and ≥2 m tall/ha (6.6 ft tall/2.5 ac), in A) western Oregon, USA (county boundaries shown in black), and B) U.S. Forest Service National Forests (boundaries shown in red), based on data from LEMMA (2012).

Fig. 11. Locations of marijuana cultivations sites that were eradicated in western Oregon, USA, during 2004–2012. Light black lines represent county boundaries and bold black line represents proposed West Coast Distinct Population Segment boundary in Oregon. Data based on Oregon High Intensity Drug Trafficking Area (2013) and presented in U.S. Fish and Wildlife Service (2014c). Figure courtesy of U.S. Fish and Wildlife Service.

Fig. 12. Feasible release areas (red border) for reintroduction of fishers within three U.S. Forest Service National Forests (light black lines represent boundaries) on the west slope of the Cascade Range, western Oregon, USA. Each potential release area represents approximately 1,280 km2 (494 mi2), or 20 non-overlapping home ranges of female fishers (64 km2/fisher [24.7 mi2/fisher]) based on data from Washington (Lewis 2014). Bold black lines represent major paved roads and blue lines represent major rivers (rivers shown at 1:2,000,000 scale); selected roads and rivers are labeled for spatial reference.

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INTRODUCTION

The distribution of fishers (Pekania pennanti) across much of northern North America generally has been stable or increasing since the 1950s, with successful population recovery seemingly linked to areas with continuous boreal forests (Powell 1981, Gibilisco 1994). However, relatively small and isolated populations currently exist at the edges of their distribution, some of which have become peninsular in the Pacific Northwest, including through reintroduction efforts (Gibilisco 1994, Zielinski et al. 1995, Aubry and Lewis 2003).

The fisher was once widely distributed throughout forested areas of western Oregon, but due to logging, unregulated harvest, and perhaps incidental mortalities associated with predator-control efforts, the range of the species has been reduced to one remnant indigenous population and one reintroduced population in southwestern Oregon (Mace 1979, Aubry and Lewis 2003, ODFW 2006a; Fig. 2). The indigenous Siskiyou population is limited to the Klamath Mountains west of Ashland and south of Grants Pass and into northern California. The southern Cascades population, located near Crater Lake National Park, was reintroduced by the Oregon Department of Fish and Wildlife (ODFW) with fishers from British Columbia and Minnesota (Kebbe 1961, Oregon State Game Commission 1961, Aubry and Lewis 2003, Hiller 2011). Records suggest that more fishers were released in southwestern compared to northeastern Oregon (Aubry and Lewis 2003), which may partially explain reintroduction success in the former (Lewis et al. 2012).

Although monitoring has been limited there is no evidence that the two populations in western Oregon have increased in size or expanded their range during the past 20 years. There has been no evidence of genetic interchange between populations. Apparent genetic isolation between the two populations (separated by about 75 km [47 mi]) may be the result of potential anthropogenic (e.g., Interstate Highway 5, urban and agricultural development) and ecological (e.g., Rogue River, open grassland, oak savanna) movement barriers (Aubry et al. 2004; see also Tucker 2013). There is, however, recent genetic evidence that a male from the indigenous population crossed these barriers and was detected within 30 km (19 mi) of the reintroduced population (Pilgrim and Schwartz 2012). Also, very recent detections of fishers suggest potential limited expansion of the indigenous population (e.g., about 24 km (15 mi) west and about 40 km (25 mi) south of Crater Lake) and potential for genetic interchange with the reintroduced population (J. Chatel, U.S. Forest Service, personal communication). In addition to the successful reintroduction that resulted in the current southern Cascades population, various other reintroduction attempts during 1961–1981 apparently failed in Oregon, including near Klamath Falls (Cascades in southwestern Oregon) and near La Grande (Wallowa Mountains in northeastern Oregon) (Kebbe 1961, Aubry and Lewis 2003).

Fishers have been classified as Martes pennanti, although re-classification to the genus Pekania has recently been suggested (Sato et al. 2012) and adopted by the U.S. Fish and Wildlife Service (2014a,c), Bradley et al. (2014), and others. Three subspecies of fishers were designated by Hall (1981), although this taxonomy has been questioned and has received little attention in the scientific literature (Hagmeier 1959, Powell et al. 2003). The use of subspecies designations is largely avoided in this assessment, although reference to some published research may require mention of subspecies. Feasibility assessment for reintroduction of fishers in western Oregon, USA 12

The fisher currently is not listed under the Oregon Endangered Species Act (Oregon ESA), but is listed by ODFW in the Oregon Conservation Strategy as a Strategy Species, and is also considered a Sensitive Species, Critical Category, with the suggestion that the feasibility of reintroduction be assessed if populations fail to expand (ODFW 2006a). Harvest of fishers in Oregon has been prohibited since 1937 (Aubry and Lewis 2003). However, as with adjacent states, the protected status of fishers in Oregon has not resulted in population recovery. The fisher in the proposed West Coast DPS, including western Oregon (Fig. 3), was classified as a candidate for listing as a federally threatened or endangered species by the U.S. Fish and Wildlife Service in 2004. During March 2013, the U.S. Fish and Wildlife Service opened an information collection period to assess whether fishers in western California, Oregon, and Washington continued to warrant protections under the federal ESA. A proposal to list the West Coast DPS as threatened under the federal ESA was published in the Federal Register on 7 October 2014, with comments accepted until 4 February 2015 (U.S. Fish and Wildlife Service 2014a,b). More detailed information on petitions to list, court actions, and references to other fisher-related Federal Register publications are provided by Lofroth et al. (2010) and U.S. Fish and Wildlife Service (2014a).

Among carnivores, the fisher is one of the most successfully reintroduced species. Of 30 reintroduction efforts examined by Lewis et al. (2012), 77% with known outcomes were successful. The successful reintroduction of fishers in western Oregon north of the existing populations would broaden the distribution of the fisher in its historical range and over time may restore connectivity among fisher populations in the Pacific Northwest, particularly with the recent and ongoing reintroductions of fishers in Washington (e.g., Lewis 2014). The conservation goals of reintroducing fishers into western Oregon include establishing additional viable populations, but also in the long-term, for these populations to become connected to each other and to existing populations. The alternative to reintroduction efforts (i.e., maintain status quo) is unlikely to achieve recovery because the two existing populations likely have not experienced more than very limited, if any, expansion during past decades.

HABITAT AVAILABILITY

The strong positive relationship between reintroduction success (i.e., re-establishing a viable population) and habitat quality is intuitive and has been described for translocations involving both avian and mammalian taxa (Griffith et al. 1989). Indigenous populations of fishers once existed throughout much of western Oregon, but it cannot be assumed that current habitat conditions are appropriate. An assessment of habitat conditions is necessary to minimize risks of reintroduction failure, particularly for species that require large areas for home ranges such as fishers (e.g., Powell 1981, Weir and Almuedo 2010).

Releases into suboptimal habitat have been cited as one of the primary issues related to reintroduction failures for fishers (Lewis et al. 2012). An assessment of habitat availability is a critical step to determine the feasibility of reintroduction and such assessments should be considered at multiple spatial scales (Aubry and Lewis 2003). A description of habitat may be parsed into a coarse spatial-scale assessment (i.e., geographic distribution in western U.S.) and a fine spatial-scale assessment (i.e., within home range and finer scales). Coarse spatial scales Feasibility assessment for reintroduction of fishers in western Oregon, USA 13

may be the most useful for assessing habitat selection by fishers (Carroll et al. 1999). A recent synthesis of fisher habitat in western North America (Raley et al. 2012) and a recent meta- analysis on fisher habitat related to resting sites (Aubry et al. 2013) were important sources of information to describe potential fisher habitat availability in western Oregon. A recent modeling effort of potential fisher habitat in western Oregon (Fitzgerald et al. 2014, U.S. Fish and Wildlife Service 2014c) provides the primary basis for determining coarse-scale habitat availability in this assessment.

Coarse-scale Habitat Availability

General patterns of coarse-scale habitat for fishers include complex forest structure (as opposed to tree species composition); wet-to-mesic mid- to late-seral forests (as opposed to strictly old- growth forests); preference of relatively high canopy closure and avoidance of open areas (in terms of both horizontal and vertical structure); and preference of areas with no snow, or shallow or packed snow (rather than deep powdery snow), are important factors (e.g., Buskirk and Powell 1994, Weir and Harestad 1997, Zielinski et al. 2004a, Davis et al. 2007). Moderate-to-high canopy closure has been described as a critical habitat component for fisher at all spatial scales, is associated with resting sites and foraging activities, and may offer thermal benefits and decreased predation (Raley et al. 2012). Dense canopy cover may mediate effects of high snowfall to some extent while also reducing predation risk, therefore providing multiple benefits to fishers (Raley et al. 2012). However, some level of flexibility in these general patterns may exist. For example, a mosaic of structural stages (i.e., a mixture of successional stages as opposed to domination by either early or late stages) may be beneficial for or used by fishers in British Columbia (Weir and Almuedo 2010), in southwestern Oregon (Clayton 2013), and in California, including managed forests (Self and Kerns 2001). Similarly, detections of fishers in northwestern California did not seem to be related to stand age or old-growth forests, although the latter was uncommon in that area (Klug 1997). In Washington, fishers have also been observed using mixed landownerships, including state, federal, tribal, and private lands (Happe et al. 2014). Positive population responses of some small mammal species to some timber management practices (e.g., Waldien 2005; see Prey Base section), resulting in earlier successional stages that retain some desirable structural components, may influence use of these areas by fishers.

In the Pacific Northwest, habitat-selection studies have shown that fishers are strongly associated with low- to mid-elevation forest cover, mixed hardwood-conifer forests, high canopy closure, complex horizontal and vertical structure, and forests with medium- to large-sized trees (e.g., Carroll et al. 1999, Zielinski et al. 2010, Raley et al. 2012). In western Oregon, relatively high levels of canopy cover exist in the Cascade and Coast Ranges, particularly on the Mt. Hood, Umpqua, and Willamette National Forests in the Cascades (Fig. 4). Historically, fishers in the Pacific Northwest were most common at elevations <2,500 m (8,200 ft), but amount of snow cover and snow type may affect their elevational distribution; for example, wetter and deeper snow on the west slope of the Cascades could result in few fishers at >1,000 m (3,300 ft), whereas the shallower snow on the east slope may result in few fishers at >2,200 m (7,200 ft) (Aubry and Houston 1992, Powell and Zielinski 1994). Most of the forested area west of the peak of the Cascades is <1,000 m in elevation, whereas within the western Oregon counties generally east of the peak of the Cascades there is a substantial amount of forested area between Feasibility assessment for reintroduction of fishers in western Oregon, USA 14

1,000 and 2,200 m (Fig. 5). U.S. Forest Service lands in western Oregon include a substantial amount of contiguous forest within these elevational ranges (Fig. 5).

An assessment of fisher habitat value and connectivity in portions of California, Oregon, and Washington, which includes the feasibility assessment area, was conducted by the U.S. Fish and Wildlife Service (2014c; Fitzgerald et al. 2014; see these references for detailed information) as part of the species evaluation for the proposed listing as threatened under the federal ESA (U.S. Fish and Wildlife Service 2014a). For modeling purposes, western Oregon was divided into 6 regions: Oregon Coast; South Oregon Coast; Klamath and South Cascades; Coast Range and Klamath Overlap (collectively, Coast-Southwestern Oregon); Western Cascades, and Eastern Cascades (collectively, Oregon Cascades). Habitat suitability throughout the Coast- Southwestern Oregon was modeled using the software Maxent (see Baldwin 2009 for more information on maximum entropy modeling in wildlife research) and habitat characteristics (independent variables related to climate [e.g., temperature and precipitation characteristics], topography [e.g., slope, elevation, ruggedness], forest structure [e.g., forest type, stand age]) related to fisher detections (presence only). This approach was used for regions that contained suitable fisher detections and extrapolated to include regions that were environmentally similar but that included no suitable detections. This complex process included, among other steps, constructing a full model of covariates using logistic methods, evaluating that model, and reducing model complexity without significantly reducing model performance (i.e., prediction quality), which resulted in the final model.

Habitat suitability for the Oregon Cascades, where fisher detection data were insufficient and environmental conditions were different from regions containing such data, was modeled using information obtained from an expert panel (i.e., an expert model). This approach was based on independent variables similar to those used during the Maxent approach and deemed important from the literature and by experts, indexing or otherwise quantifying values in each spatial data set, and using a logistic regression approach with thresholds to determine habitat value. Outputs from the Maxent model and the expert model were combined to categorize habitat quality for fishers (Fig. 6).

Qualitative results suggest that in western Oregon, large contiguous high-quality habitat exists on the west slope of the Cascade Range, from about 120 km (75 mi) north of the California border and continuing north to the Washington border (Fig. 6). Several large tracts (but smaller and more fragmented compared to the west slope of the Cascades) of high-quality habitat may also exist in the Coast Range from about 150 km (93 mi) north of the California border and continuing north to the Washington border. Similar to a fisher habitat assessment conducted for Washington (Lewis and Hayes 2004), high-quality fisher habitat in Oregon seems largely confined to lands under public management and ownership, particularly U.S. Forest Service lands (Figs. 7 and 8).

Fine-scale Habitat Assessment

Fine-scale habitat for fishers can be parsed into two primary activities: resting and foraging (Buskirk and Powell 1994), but denning is also included here. Habitat related to foraging activities is closely associated with prey base and is included in the Prey Base section below. Feasibility assessment for reintroduction of fishers in western Oregon, USA 15

Resting Sites

Based on a meta-analysis, Aubry et al. (2013) found that the attributes fishers selected for at resting sites (i.e., used more than expected, based on availability) included steeper slopes, denser overhead cover, greater amounts of coarse woody debris, and larger forest structures. Specific structures may include branches (typically with abnormal growths caused by mistletoe or brown rusts [fungi]; collectively called witch’s brooms), tree cavities, coarse woody debris, and ground dens (e.g., rock piles; burrows excavated by other species, including mountain beavers [Aplodontia rufa]) (Weir et al. 2004, Lewis and Happe 2009). Cavities may be selected more often by females, whereas platforms (e.g., nests, mistletoe or witch’s brooms) may be selected more often by males (Zielinski et al. 2004b). However, live trees (e.g., Douglas-fir [Pseudotsuga menziesii], western hemlock [Tsuga heterophylla]) with mistletoe brooms were highly used by both males and females, particularly the latter, in the southern Cascades of Oregon (Aubry and Raley 2006). Structures used as resting sites were typically 40–240% larger than randomly selected structures and throughout western North America, decadent live trees were most commonly used (see Raley et al. 2012). Selection of resting sites has potential benefits associated with reduced thermal stress (an energetic advantage), reductions in predation risk due to dense cover, and perhaps increased prey access and consumption based on coarse woody debris and other factors (see Raley et al. 2012, Aubry et al. 2013).

During cold weather extremes, fishers in central British Columbia selected rest sites associated with coarse woody debris (e.g., large single pieces of debris, smaller multiple pieces of debris associated with logging activities), that offered the greatest thermal benefit compared to other types of resting sites (Weir et al. 2004). During winter, cavities in live trees may offer greater thermal benefits than cavities in dead trees by buffering the effects of ambient temperatures (Coombs et al. 2010), although subnivean spaces were highly selected by fishers during the coldest temperatures (Weir et al. 2004). A meta-analysis of studies conducted from the southern Sierra Nevada to northern British Columbia suggested that fishers selected resting sites that were cooler and wetter than what was available (Aubry et al. 2013). The highest amounts of cover of down wood in western Oregon are along the west slope of the Cascades, particularly in the Mt. Hood, Umpqua, and Willamette National Forests, and in northwestern Oregon primarily on state lands (Figs. 7–9).

Denning Sites

Appropriate den sites used for reproduction are also a critical fine-scale habitat feature because female fishers are obligate cavity users in snags, decadent trees, and suitable large live trees, and females require multiple dens sites within a season for relocating young (Powell 1993, Powell et al. 1997, Raley et al. 2012). Availability of den sites may be critical for population recovery because of the low reproductive rates of fishers (Powell and Zielinski 1994). A literature review that included data describing 330 dens indicated that a majority of den sites were in larger, older trees, in cavities caused by heartwood decay, and with relatively small entrances high off the ground (Raley et al. 2012). In the southern Cascades of Oregon, female fishers used snags as natal (i.e., birthing) dens in incense cedar (Calocedrus decurrens), western white pine (Pinus monticola), and true fir (Abies spp.), with mean diameter-at-breast height, height, and height to cavity entrance of 89 cm (35 in), 26 m (85 ft), and 16 m (52 ft), respectively (Aubry and Raley Feasibility assessment for reintroduction of fishers in western Oregon, USA 16

2006). Cavities used for maternal (i.e., post-natal, as kits start becoming mobile) dens were more variable (e.g., live trees, snags, hollow logs) and often larger structures than those used as natal dens (Aubry and Raley 2006). In western Oregon, the density of snags is generally highest on the west slope of the Cascades, the majority of which falls within the Mt. Hood, Umpqua, and Willamette National Forests (Fig. 10), subject to potential differences in sampling rates in stands that experienced burns or disease with stands that did not (H. Roberts, Landscape Ecology, Modeling, Mapping & Analysis Team, personal communication). Potential selection of release areas suitable for reintroduction of fishers can rely on the coarse-scale habitat modeling conducted by the U.S. Fish and Wildlife Service (2014c), the primary source in this assessment. However, consideration of specific release sites should also consider fine-scale habitat features (e.g., proximity to roads, proximity to other potential release sites) during decision making (see Table 3).

PREY BASE

Buskirk and Powell (1994) suggested that fishers are less selective in areas used for foraging than in areas used for resting. In contrast to their routine selection of elevated rest and den sites, fishers forage primarily in a terrestrial manner (see Powell and Zielinski 1994). Open expanses, even those that may contain higher prey abundance, are avoided during foraging, as with other behaviors (Powell and Zielinski 1994). Fishers are considered generalist and opportunistic predators, and with the possible exception of porcupines (Erethizon dorsatum), fishers appear to have little effect on prey population dynamics or community structure (Aubry et al. 2003).

Important food items for fishers include snowshoe hares (Lepus americanus), porcupines, other rodents (e.g., squirrels [Sciuridae]), and carrion (Powell 1981, Roy 1991, Martin 1994, Powell and Zielinski 1994). However, fishers persist in areas and have higher diet diversity where snowshoe hares and porcupines are rare or absent (e.g., southern Sierra Nevada, California; Zielinski et al. 1999, Zielinski and Duncan 2004). Proportions of prey species in fisher diets vary across their range, with prey diversity lowest in mid-western and western states (Martin 1994). Size of prey items consumed may be related to sexual-size dimorphism in fishers, with larger males more frequently consuming larger prey (Kelly 1977, Weir et al. 2005, Raley and Aubry 2009). Fishers may respond to annual fluctuations or cycles in prey species by switching to alternative prey (Bowman et al. 2006). In addition to prey abundance, the availability, accessibility, size, and behavior of prey species and populations may affect habitat selection and space use by fishers (Buskirk and Powell 1994). For example, in areas with sufficient overhead cover, fishers may select areas with higher diversity of prey species (Kelly 1977). Within the reintroduced southern Oregon Cascades population, Leporidae (e.g., snowshoe hares, brush rabbits [Sylvilagus bachmani]) and Sciuridae (e.g., California ground squirrel [Otospermophilus beecheyi], Douglas’ squirrel [Tamiasciurus douglasii], golden-mantled ground squirrel [Callospermophilus lateralis], northern flying squirrel [Glaucomys sabrinus]) were important prey items, especially during denning periods (Aubry and Raley 2006, Raley and Aubry 2009). Populations of several small mammal species are positively associated with early successional forest stages, particularly stages that retain structural complexity and a mosaic of patches containing different tree densities (e.g., Carey and Wilson 2001, Waldien 2005, Klenner and Sullivan 2009). Feasibility assessment for reintroduction of fishers in western Oregon, USA 17

Snowshoe Hares

The range of snowshoe hares overlaps much of the range of fishers throughout North America, and hares are one of the most common prey species for fishers (Powell and Zielinski 1994). Snowshoe hare populations in southern portions of their range, including Oregon, apparently do not exhibit a periodic cycle (Murray 2000), which could provide a more stable annual food source for fishers than in areas with strongly cyclic hare populations. In north-central Washington, hare densities were positively correlated with density of large shrubs, saplings, and medium trees in areas dominated by Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) (Lewis et al. 2011). Hares in western Oregon on managed forests have been associated with second-growth Douglas-fir containing slash piles and western hemlock (Black 1965), and with areas of greatest canopy closure (Verts and Carraway 1998 [using data from Black 1965]). Densities of snowshoe hares have been positively correlated with vegetation cover density (Ivan et al. 2014). No population estimate or index is known to exist for hares in Oregon.

Porcupines

Where porcupines and fishers are sympatric, porcupines are a prey item, but snowshoe hares are usually more common in fisher diets (Powell and Zielinski 1994). Porcupines are distributed throughout Oregon (Verts and Carraway 1998), but may reach relatively high densities in mixed- conifer forests (e.g., Douglas-fir, ponderosa pine [Pinus ponderosa]) and on the west slope of the Cascades (see Verts and Carraway 1998). The impetus behind reintroduction of fishers in southwestern Oregon during the 1970s and 1980s was the desire to control porcupines that were causing substantial damage to trees with high economic value (Aubry and Lewis 2003, Lewis et al. 2012). No population estimate or index is known to exist for porcupines in Oregon. Populations of porcupines may have decreased during recent decades (or may exist at very low densities in western Oregon; J. Doerr, J. Chapman, U.S. Forest Service, personal communications), perhaps in response to damage-control efforts or an epizootic in some areas.

Other Rodents

During winter, fishers generally hunt above the snow because, unlike smaller mustelids, they are incapable of effectively preying on small mammals in subnivean spaces. With the hibernation or inactivity of many small mammals, winter probably offers the fewest number of prey species available by season (Powell 1993). Species composition of small mammal communities in the western hemlock zone in Washington was found to be similar among naturally regenerated, managed (clearcutting-regenerated), and old-growth forests, although abundance was highest in old-growth forests (Carey and Johnson 1995).

The Douglas’ squirrel and northern flying squirrel are two common sciurids in western Oregon (Carey 1995). Douglas’ squirrel populations are important to southern Cascades fisher populations in Oregon (Aubry and Raley 2006, Raley and Aubry 2009). Populations of this species can fluctuate substantially by both season and year; abundance is believed to be positively associated with cone production by Douglas-fir and western hemlock and may be higher in old-growth forests (Buchanan et al. 1990, Verts and Carraway 1998; but see Carey Feasibility assessment for reintroduction of fishers in western Oregon, USA 18

1995). The northern flying squirrel was a common prey item of reintroduced fishers in Oregon (Aubry and Raley 2006, Raley and Aubry 2009). Abundance of this arboreal squirrel seems to be positively associated with abundance of large snags and ericaceous shrubs (e.g., salal [Gaultheria shallon], huckleberry [Vaccinium spp.]), and forests dominated by Douglas-fir had higher squirrel abundances compared to forests dominated by western hemlock (Carey 1995).

Mountain beavers were described as a potentially important prey species in Washington, and fishers have used dens of mountain beavers as rest sites (Lewis and Hayes 2004, Lewis and Happe 2009). Mountain beavers occur throughout forested areas in western Oregon, with abundances higher in early to mid-seral stage second-growth forests with diverse vegetation and sufficient ground debris (Carraway and Verts 1993). Industrial timber managers routinely implement lethal and non-lethal control measures in forest seedling plantations in an effort to mitigate the economic losses on their properties that occur as the result of mountain beaver foraging (e.g., Arjo 2006). No population abundance estimate or index is known to exist for mountain beavers in western Oregon. However, their purported abundance in western Oregon may be beneficial to fishers, especially in areas with low abundance of snowshoe hares or porcupines.

Another potentially important group of prey species in western Oregon are woodrats. Bushy- tailed woodrats (Neotoma fuscipes) are distributed throughout Oregon, whereas dusky-footed woodrats (Neotoma cinereus) occurs in western Oregon except for the Coast Range (Verts and Carraway 1998). The more widespread (in Oregon) bushy-tailed woodrat may be abundant on rocky bluffs on the west slope of the Cascades and also mixed-conifer forests (Carey et al. 1999). Woodrats were detected in only a very small percentage of fisher scats in the reintroduced fisher population in the southern Cascades (Aubry and Raley 2006), but were used as prey more than expected in northern coastal California (Golightly et al. 2006). Lastly, although white-footed (Peromyscus leucopus) and deer mice (Peromyscus maniculatus), along with meadow (Microtus pennsylvanicus) and red-backed voles (Clethrionomys gapperi), are common in both fisher habitat and in fisher diets, their relative value as prey items is probably not as high as larger prey species (Powell and Zielinski 1994).

INTERSPECIFIC EFFECTS

Interspecific effects related to fishers include interspecific killing of fishers (i.e., other carnivores killing fishers) and potential negative effects of fishers on other wildlife species of concern (e.g., competition, predation). The discussion of interspecific killing is limited to carnivore species that have been known to cause direct mortality of fishers and that are relatively common in western Oregon. Wildlife species in western Oregon that may be negatively affected by the reintroduction of fishers are limited to those of state and federal concern (Table 1).

Interspecific Killing of Fishers

Carnivore communities in western Oregon include black bears (Ursus americanus), bobcats (Lynx rufus), coyotes (Canis latrans), gray foxes (Urocyon cinereoargenteus), mountain lions (Puma concolor), raccoons (Procyon lotor), red foxes (Vulpes vulpes), ringtails (Bassariscus Feasibility assessment for reintroduction of fishers in western Oregon, USA 19

astutus), river otters (Lontra canadensis), and others. However, bobcats, mountain lions, and coyotes are the primary species of interest with regards to interspecific killing of fishers.

It has become widely accepted that fishers in the western U.S. are subject to high rates of predation by larger carnivores (Lofroth et al. 2010). Recent, as well as older, investigations of fisher mortality indicate that the primary mortality source for fishers in most California populations is interspecific killing by other carnivores (Buck et al. 1983, Truex et al. 1998, Gabriel 2013, Wengert et al. 2014a). Wengert et al. (2014a) found that 61% of all fisher mortalities and 73% of female fisher mortalities were attributed to interspecific killing. In California, Gabriel (2013) found that 52% of all fisher mortalities and 71% of female fisher mortalities were a result of interspecific killing. Unfortunately, similar information related to interspecific killing of fishers in Oregon is generally lacking.

Bobcats and mountain lions appear to be the most frequent carnivores associated with interspecific killing of fishers in California (Wengert et al. 2014a). Both coyotes and great- horned owls (Bubo virginianus) have been suspected (Buck et al. 1983) and coyotes have been confirmed as having killed fishers in at least four cases, but in general, the frequency of coyotes having killed fishers seems low (Wengert et al. (2014a). Bobcats accounted for >42% of all female fisher mortalities in California, demonstrating the importance of bobcat-fisher interactions in this population (Wengert et al. 2014a). Data on interspecific killing of fishers in Oregon is very limited. Within the indigenous population in southwestern Oregon, a radiomarked male fisher was killed by a mountain lion (G. M. Wengert, Integral Ecology Research Center, and C. M. Thompson, U.S. Forest Service, unpublished data), but the small sample of fisher mortalities from that project precludes any generalizations about the frequency of interspecific killing in that population.

Historically, interspecific killing was thought to be more influential in translocated fisher populations than in resident populations (Powell and Zielinski 1994). Aubry and Raley (2006) monitored fishers in the established reintroduced population in the southern Cascades of Oregon and identified coyotes and mountain lions as predators, although only 2 female fishers experienced interspecific killing of the 22 captured and radiomarked during the 6-year study; no males were known to have been killed by predators. Additionally, the 2 predation events comprised only about 33% of all female mortalities, a much smaller percentage of overall mortality compared to resident populations in California (see Gabriel 2013). In a reintroduced fisher population in the Olympic Peninsula of Washington, 58–68% of total female fisher mortalities with known causes (n = 19) were the result of interspecific killing, whereas 43–71% of total male fisher mortalities with known causes (n = 7) were the result of interspecific killing (Lewis 2014). In most instances, the carnivore species involved could not be identified, although for at least 2 female fisher mortalities, bobcats were documented as responsible. In a fisher reintroduction project in the northern Sierra Nevada of California, 15 fisher mortalities were recovered, though only 9 were in a condition suitable to make inferences about cause-specific mortality. Of these 9 mortalities, 5 were suspected to have been interspecific killing; of these 5 mortalities, 4 were confirmed or strongly suspected to have been from bobcats (Powell et al. 2014).

Feasibility assessment for reintroduction of fishers in western Oregon, USA 20

Given the similar percentages of mortality due to interspecific killing in reintroduced and resident populations in California, Oregon, and Washington, it seems likely that any newly reintroduced fisher populations in western Oregon would experience similar rates of interspecific killing. Many factors probably affected the rates of interspecific killing for mesocarnivore populations, including interspecific competition for prey, predator population abundance, and habitat characteristics that foster or inhibit this interaction. Prey populations are typically heterogeneous across a landscape, being influenced by vegetation types, stage of succession, and other biotic and abiotic features (see Prey Base section). Additionally, population densities of predators may not have a direct relationship with rates of interspecific killing (Vucetich et al. 2002), as higher-order interactions among predator species, such as competition and intraguild predation, may decrease predation pressure on the intraguild prey species (in this case, fishers).

Risk of interspecific killing is likely strongly influenced by habitat structure (Janssen et al. 2007). Timber-harvest regimes, fuel breaks, agricultural breaks, wildfire, and other forms of disturbance likely affect carnivore densities and resource selection. However, very few studies of habitat use by bobcats have been conducted in coniferous or mixed coniferous-hardwood forests in the western U.S. A study on bobcat and coyote resource selection in the Coast Range of southwestern Oregon found that both species used forested and open areas in relation to their availability (Witmer and deCalesta 1986). Within clear-cuts, bobcats more frequently used shrub stages of clear-cuts, whereas coyotes more frequently used earlier successional stages, such as grass and forb vegetation types. Because research on bobcats in Oregon is very limited, an understanding of how bobcats select resources must rely on studies conducted in other areas with comparable habitat characteristics. For example, bobcats highly selected open, brushy, and open shrubby areas over forested areas in northern coastal California (Wengert 2013). Bobcats in the coniferous and mixed coniferous-hardwood forests of the southern Sierra Nevada selected herbaceous areas over any other forest type (Wengert et al. 2014b). Based on these studies, it is likely that bobcats occupying forested areas of the Pacific Northwest select brushy and open shrubby areas over those that are heavily forested.

The most informative study on the potential for reintroduced fishers to be killed by bobcats was conducted in northern coastal California; this study included an investigation of simultaneous space use of bobcats and fishers and characterized the habitat conditions at sites where interspecific killing of fishers occurred (Higley et al. 2013, Wengert 2013). Higley et al. (2013) found that fishers were at greatest risk of interaction with bobcats where drivable road density was high, where ecotones between forest and non-forest habitat types were more common, or in or near brushy or open areas. Wengert (2013) found that the portions of fisher home ranges that overlapped with bobcat core-use areas contained a higher proportion of open areas than the portions of fisher home ranges that did not overlap bobcat core-use areas.

Although bobcats seem to be the primary carnivore responsible for mortalities of female fishers in the western U.S., mountain lions were responsible for most mortalities of both male and female fishers at the southern extent of the fisher range in California (Wengert et al. 2014a). No data exist on space use or resource selection by sympatric mountain lions and fishers, but a recent study on mountain lions in the central Sierra Nevada may offer some insights into how these large carnivores use the types of coniferous and mixed coniferous-hardwood forests that fishers might also use. In this study, mountain lions frequently used roads to travel between Feasibility assessment for reintroduction of fishers in western Oregon, USA 21

foraging or resting areas (Orlando 2008), which may increase the likelihood of interactions with fishers. Additionally, mountain lions selected for montane hardwoods and chaparral and selected against conifers (Orlando 2008).

Mandatory harvest reporting by hunters and trappers indicates that bobcats are distributed throughout the state and that harvests in western Oregon are highest in Douglas, Lane, and Linn counties (Hiller 2011). However, no population estimate or index currently exists for bobcats in Oregon, and basic harvest data alone do not necessarily reflect population trends. Mountain lions are also distributed throughout Oregon, with the greatest relative densities in western Oregon occurring in the southwestern Cascades, the lowest occurring from the Willamette Valley west to the Pacific coast, and intermediate occurring in the remainder (ODFW 2006b). Lastly, as with bobcats, no population estimate or index exists for coyotes in Oregon. Mandatory harvest reporting by hunters and trappers in western Oregon indicates that harvest of coyotes is highest in Douglas and Linn counties (Hiller 2011). However, in certain situations (e.g., damage management) there is no regulatory mechanism that requires reporting coyote harvest in Oregon, so the total number of mortalities from anthropogenic sources other than regulated hunting and trapping activities is unknown.

Some conclusions may be drawn about bobcat and mountain lion habitat use in areas with sympatric fishers that may be important for selecting release areas for fisher reintroductions in Oregon. Interactions, and thus, the risk of predation by bobcats on fishers probably increases in open, brushy, or shrubby areas, and decreases in mature and young, multi-storied forest. In addition, road density and substantial ecotones between forested and non-forested areas facilitate bobcat movement and activity and may pose increased risks of interspecific killing of fishers by both bobcats and mountain lions. Finally, although population estimates or indices for bobcats (and coyotes) are not available, both the indigenous and the reintroduced fisher population in southwestern Oregon occur in areas containing relatively high mountain lion populations. Interspecific killing may be a contributing factor to the lack of or very limited expansion of either or both of these fisher populations, although each population has maintained long-term viability.

Potential Effects on Species of Concern

During the past century or more, the composition and distribution of wildlife communities in Oregon (and other states) has changed dramatically. Numerous species have been extirpated (e.g., grizzly bears [Ursus arctos]), are currently in low densities (e.g., wolverines [Gulo gulo]), or are experiencing population recovery (e.g., gray wolves [Canis lupus]) in Oregon. Balancing the costs or risks of a reintroduction effort (e.g., potential effects on species of concern) with the benefits (e.g., improving conservation status, restoring ecosystem function) should be included in a feasibility assessment (International Union for Conservation of Nature 2014). Reintegration of a mesocarnivore into western Oregon ecosystems requires consideration of the potential effects of that species on other species of concern to the greatest extent possible. In this document, species of concern include a relevant subset of those listed in the Oregon Conservation Strategy (ODFW 2006a), Oregon ESA, federal ESA, and federal Interagency Special Status/Sensitive Species Program (ISSSSP) (Table 1).

Feasibility assessment for reintroduction of fishers in western Oregon, USA 22

Marten

In North America, fishers and martens (American marten [Martes americana], Pacific marten [M. caurina]; see Dawson and Cook [2012] for recent proposed taxonomic changes) are sympatric over much of their distribution, particularly in some Great Lakes and northeastern U.S. states, and Canadian provinces (see Gibilisco 1994). In Oregon, martens occur in the Cascade, Blue, and Wallowa Mountains, and to a much lesser extent, the Coast Range and coastal forests (Verts and Carraway 1998, Zielinski et al. 2001). Interspecific competition between fishers and martens, and marten mortalities caused by fishers, do not generally seem to affect their populations, but may have been a contributing factor in the decline of Humboldt marten (M. a. [c.] humboldtensis) populations in coastal California (Krohn et al. 1997, Aubry et al. 2003).

The Humboldt marten, a lower-elevation coastal subspecies, was thought to be extinct until the rediscovery of a remnant population in coastal California during 1996 (see Zielinski et al. 2001). Oregon has two known populations of coastal martens, one in the central coast (generally Douglas, Lane, and Lincoln counties) and one in the southern coast (generally Coos and Curry counties). These populations are assumed to be isolated, separated by about 64 km (40 mi), with the southern coastal population about 80 km (50 mi) from the single known population in coastal California. Although sample sizes were very limited, a genetics study suggested that martens in coastal Oregon were more similar (e.g., shared a common haplotype) to those in coastal California than to martens in Oregon’s Cascades (Slauson et al. 2009). The U.S. Fish and Wildlife Service (2014d) issued a scoping notice requesting information on the status of coastal martens in California and Oregon during June 2014, with a 12-month finding to be published in April 2015.

Krohn et al. (1995) described the hypothesis that deep, soft snow reduces fitness of fishers (e.g., through increased energetic demands, thereby affecting survival or reproduction) and therefore is one factor that limits their populations, whereas sympatric marten populations may be limited by presence of fishers. These hypotheses were later tested by Krohn et al. (1997) using historical and current distribution data of both species in California; their results suggested that mean monthly snowfall during winter months (Dec–Mar) in forested areas occupied by each species may affect distributions such that fishers were associated with <13 cm (<5 in) of snow, martens with >23 cm (>9 in) of snow, and both species with 13–23 cm (5–9 in) of snow. However, fishers and martens were once sympatric in coastal areas of Oregon (Bailey 1936), where snowfall is generally absent. In such areas, fishers and martens may co-exist by partitioning food resources (Aubry et al. 2003). Furthermore, coastal martens are strongly associated with dense understory cover, which appears to limit competitively dominant species such as the fisher (Slauson et al. 2007). Decreased snowpack would seem to favor fishers over martens and may result from climate change (Krohn et al. 2004).

Using baited camera stations at elevations ranging from 586 to 2237 m (1,923 to 7,339 ft), McFadden-Hiller and Hiller (2015) detected marten from 1,252 to 2,237 m (4,107 to 7,339 ft) in elevation during a 2-year study in the Oregon Cascades. Radiomarked fishers in the reintroduced southern Oregon Cascades population rarely used areas >1,554 m (5,100 ft) in elevation (Aubry and Raley 2006), suggesting relatively minimal overlap in elevation between species in the Cascades, although other factors affecting distribution are also likely involved. Feasibility assessment for reintroduction of fishers in western Oregon, USA 23

Fishers seem to exhibit greater plasticity in their diet than martens, although dietary overlap between species seems relatively high (Martin 1994). However, the primary prey species in many instances were snowshoe hares and porcupines for fishers and voles for martens (e.g., Martin 1994, Powell and Zielinski 1994). Some level of prey overlap would be expected in western Oregon, but the actual level of direct competition for food resources is unknown at this time. However, given the putative differences in elevation and occupancy overlap, potential negative effects of fishers on marten populations should be minimal in the Cascade Range compared to the Coast Range in Oregon.

Gray Wolf

Gray wolves are currently listed as endangered throughout the state under the Oregon ESA and as endangered under the federal ESA in western Oregon within the assessment area (ODFW 2014b). Reproduction by gray wolves in the Oregon Cascades was documented during June 2014, the first since the 1940s (ODFW 2014a). With the statewide wolf population increasing in both distribution and abundance since 2009 (ODFW 2014b), multiple resident packs could establish in the Cascades. There has been no documentation of negative effects between fishers and wolves.

Marbled Murrelet

The marbled murrelet (Brachyramphus marmoratus) is listed as threatened under both the Oregon ESA and the federal ESA (Table 1). This small diving seabird nests in low-elevation old-growth coniferous forests (or mature forests with an old-growth component) typically within about 80 km (50 mi) of the shoreline of the Pacific Ocean (see U.S. Fish and Wildlife Service 1997), which seemingly limits their nesting habitat in Oregon to the Klamath Mountains and the Coast Range. The dependence of marbled murrelets on coastal forests for nesting probably results from the energetic limitations of flying between nests and near-shore foraging habitat (Hamer and Nelson 1995). Major reasons for population declines include a high rate of loss of nesting habitat (which takes 100–200 years for replacement through regrowth) and increased risk of nest predation in fragmented landscapes (U.S. Fish and Wildlife Service 1997). Nesting platforms include those formed as witch’s or mistletoe brooms and limb deformations in larger, older trees (Hamer and Nelson 1995). Such platforms are also often used by fishers as rest sites (Weir et al. 2004). Nelson and Hamer (1995) stated that predation was a major factor for nest failures and that even small increases in predation rates could substantially impact murrelet populations; they mentioned that there was no documentation of any mammalian predation on nests, but also included the fisher among several potential nest predators. Experiments using artificial nests have shown that some species of small mammals, particularly rodents, should not be ruled out as potential predators of nests or nestlings (see McShane et al. 2004). However, the lack of evidence for predation on marbled murrelet nests by mammalian predators, and the naturally low densities and extensive movements of fishers result in little concern about fishers having a negative effect on murrelet populations in western Oregon.

Feasibility assessment for reintroduction of fishers in western Oregon, USA 24

Northern Spotted Owl

The northern spotted owl (Strix occidentalis caurina) has been listed as federally threatened since 1990, with >1.8 million ha (>4.5 million ac) of critical habitat designated within western Oregon (U.S. Fish and Wildlife Service 2012b). In Oregon, old-growth forests with complex structures are characteristic of northern spotted owl habitat, and have also been described as suitable habitat for fishers (e.g., Buskirk and Powell 1994). Known predators of northern spotted owls are limited to other raptors (see U.S. Fish and Wildlife Service 2011a). Dietary overlap of fishers and northern spotted owls may occur, particularly for snowshoe hares, northern flying squirrels, and woodrats. Hares may constitute only a small proportion in owl diets compared to other prey species, but may have seasonal importance from a biomass perspective (Forsman et al. 1984). Lewis and Hayes (2004) expressed little concern about potential negative effects (e.g., competition, predation) of reintroduced fishers on northern spotted owls in the Olympic Peninsula of Washington. Similarly, there is little reason to expect negative effects of reintroduced fishers on this species in Oregon.

Oregon Spotted Frog

The Oregon spotted frog (Rana pretiosa) was listed as threatened under the federal ESA during 2014 (U.S. Fish and Wildlife Service 2014e). The historical distribution of this frog included aquatic habitats below 1,520 m (5,000 ft) and with relatively warm waters in the Klamath and Willamette Basins (Hayes 1994). Currently, these frogs are found only in Deschutes, Klamath, Jackson, Lane, and Wasco counties in Oregon (U.S. Fish and Wildlife Service 2014f). Although fisher diets can exhibit high species diversity, no mammalian predators were listed for this federally threatened species (see Cushman and Pearl 2007), suggesting that any risks to Oregon spotted frogs would be extremely low.

Red Tree Vole

The North Oregon Coast DPS of the red tree vole (Arborimus longicaudus) is a candidate for listing under the federal ESA (U.S. Fish and Wildlife Service 2011b). Red tree voles have very specialized diets, feeding almost exclusively on conifer needles, especially from Douglas-fir; they also are arboreal, spending the majority of their lives in the tops of trees and spend little time on the ground (Maser et al. 1981). In Oregon, they are found primarily in late-successional forests in the western portion of the state (Verts and Carraway 1998). Although fishers are a documented predator of tree voles (Arborimus spp.) in California (Golightly et al. 2006), this species was only a small portion of their diet. Because red tree voles are primarily arboreal and fishers spend most foraging time on the ground, fishers are unlikely to have a substantial negative effect on red tree vole populations.

Sierra Nevada Red Fox

Montane red foxes in the Oregon Cascades were once lumped with the Washington subspecies (Cascade red fox; V. v. cascadensis), but are now considered to represent the northern extent of the range of Sierra Nevada red fox (V. v. necator; Sacks et al. 2010). A determination by the U.S. Fish and Wildlife Service (2012a) about whether a listing under the federal ESA is Feasibility assessment for reintroduction of fishers in western Oregon, USA 25

warranted is scheduled to be published during 2015, which may include this subspecies in Oregon. However, very few data have been collected on Sierra Nevada red foxes, one of two indigenous montane fox subspecies (the other being the Rocky Mountain red fox [V. v. macroura] in the northeastern portion) in Oregon. Consequently, information on distribution, habitat use, demographics, prey selection, and other aspects of their ecology in Oregon are unknown at this time. The only known collection of recent field data has been from a 2-year project in the northern Cascades in portions of the Deschutes and Willamette National Forests (McFadden-Hiller and Hiller 2015; T. L. Hiller, unpublished data). Detections (digital images from baited camera stations, genetic sample analysis) of Sierra Nevada red foxes occurred at elevations ranging from 1,439 to 1,990 m (4,720 to 6,530 ft; T. L. Hiller, unpublished data). Evidence of presence of high-elevation red foxes ranges from the Mount Hood National Forest south to Crater Lake National Park and Diamond Lake in the Umpqua National Forest (e.g., A. Dyck, Mount Hood National Forest, personal communication; Hansen et al. 2013), but data related to population characteristics have not yet been collected. Potential effects of fishers on Sierra Nevada red fox are unknown, but interactions between these species are expected to be limited based on evidence of minimal elevational overlap.

Yellow-billed Cuckoo

As a Neotropical migrant, yellow-billed cuckoos (Coccyzus americanus) breed in North America and winter in parts of South America. Few studies have been conducted on this western subspecies. In the western U.S., the yellow-billed cuckoo has been described as a riparian obligate with populations that may do well in continuous riparian corridors that have undergone post-inundation revegetation (Sechrist et al. 2013). This species is listed as federally threatened in the western (U.S.) DPS, including Oregon, but currently does not appear to breed in this state (U.S. Fish and Wildlife Service 2014g). Predation of yellow-billed cuckoos generally has been limited to avian species and does not seem to be a significant threat to their populations as concluded by the U.S. Fish and Wildlife Service (2014g). Therefore, there is little reason to be concerned that reintroduced fishers would negatively affect populations of yellow-billed cuckoos in western Oregon.

Other Species

The Columbia River population of Columbian white-tailed deer (Odocoileus virginianus leucurus) is found in Clatsop and Columbia counties in northwestern Oregon, and Cowlitz and Wahkiakum counties in southwestern Washington. This population of the western-most subspecies of white-tailed deer is federally listed as endangered (see U.S. Fish and Wildlife Service 2013). Deer are generally only known in the diets of fishers as carrion and no other interspecific interactions were found in the published literature. Therefore, the reintroduction of fishers in western Oregon would not seem to have a measurable effect on Columbian white- tailed deer.

The Canada lynx (Lynx canadensis) is federally listed as threatened in the contiguous U.S. DPS, which includes Oregon, although no critical habitat designation occurs in Oregon (U.S. Fish and Wildlife Service 2014h). Between 1987 and 1993, ODFW records show 17 verified Canada lynx specimens and recognized that lynx are occasional dispersers from northern portions of their Feasibility assessment for reintroduction of fishers in western Oregon, USA 26

range and no breeding population is known to exist in the state (Hiller 2011). In western Oregon (including all of the Cascades), ODFW records show only 1 confirmation of a wolverine since initiation of record-keeping, which was on Three Fingered Jack in Linn County in 1965 (Hiller 2011). There seems to be no detections of wolverines otherwise in western Oregon despite implementation of several forest carnivore surveys during the past several decades (e.g., Farrell et al. 1996, Schlexer 2004, McFadden-Hiller and Hiller 2015). Based on the information above, any potential reintroductions of fishers in western Oregon are unlikely to have a negative impact to either wolverines or Canada lynx.

Southwestern Oregon represents the northern-most limit for ringtails (Verts and Carraway 1998). Although ringtails are considered abundant in many portions of their range, in Oregon they are listed as a Strategy Species in the Oregon Conservation Strategy (ODFW 2006a). Ringtails are currently sympatric with fishers in southwestern Oregon, so it is unlikely that potential reintroductions of fishers would negatively affect this species in Oregon.

POTENTIAL SOURCE POPULATIONS

Source populations for reintroductions should be able to sustain removals of individuals, and those removals should not affect any key ecosystem function of the source population (International Union for Conservation of Nature 2014). In addition to genetic similarity, considerations related to similarity of wildlife communities and ecosystems of source populations and reintroduction areas are important. Selection of a source population may also depend on developing reintroduction goals based on the presence of the established reintroduced non-indigenous population in western Oregon, such as potential genetic implications should populations interbreed.

Twelve haplotypes (i.e., haplotypes 1–12) have been documented among fishers in North America. Indigenous fishers in the Pacific Northwest (primarily coastal British Columbia, Washington, Oregon, and California; originally, M. p. pacifica) have one unique haplotype (#2) and share one haplotype (#1) with fishers indigenous to British Columbia (i.e., M. p. columbiana), although frequencies differed among groups for the shared haplotype (Drew et al. 2003). The reintroduced population of fishers in Oregon shares haplotypes found only in British Columbia (#9) and Minnesota (#10), which were documented to be source populations for Oregon (Aubry and Lewis 2003, Drew et al. 2003).

In an assessment of genetic consequences of translocation efforts, Drew et al. (2003) suggested that reintroduction efforts in Oregon should utilize fishers from British Columbia as the source populations because of strong evidence that historical gene flow occurred between British Columbia and California. Proximity of the source population to the reintroduction site, whereby the probability of reintroduction success decreases with increasing distance, may be one of several important considerations during reintroduction efforts of fishers (Lewis et al. 2012). However, population status and availability of fishers from candidate source populations must be incorporated into decision making (e.g., Harrington et al. 2013). Assuming that indigenous haplotypes are more desirable for potential fisher reintroduction efforts in Oregon, discussions Feasibility assessment for reintroduction of fishers in western Oregon, USA 27

start with the indigenous populations closest to Oregon and proceed with increasing distance from western Oregon for consideration of potential source populations.

Southwestern Oregon-Northern California

A high level of uncertainty is associated with the population status of indigenous fishers in southwestern Oregon-northern California. Based on a literature review by the U.S. Fish and Wildlife Service (2014c:38–39), the estimated population of fishers in this region could range from 258 to 4,018 individuals, but noted that issues may exist with estimation of bounds. Estimated fisher densities on different study areas within this population showed substantial variation, ranging from <1 fisher/100 km2 (<1 fisher/39 mi2) to 52 fishers/100 km2 (52 fishers/39 mi2) (Zielinski et al. 2004b, Thompson 2008, Matthews et al. 2011, Swiers 2013, U.S. Fish and Wildlife Service 2014c:40). Powell et al. (2012) reported that 40 fishers were removed from this population for reintroduction into the northern Sierra Nevada during 2009–2012. California may have the capacity to serve as a source population for reintroductions in Oregon at some point in the future; an assessment of effects or removals on California populations, outcomes of current pending state and federal listing decisions and other factors would need to be incorporated into such a decision (R. Callas, California Department of Fish and Wildlife, personal communication).

Southern Sierra Nevada, California

There is also a high level of uncertainty associated with estimates of abundance for the southern Sierra Nevada fisher population, but the population size is assumed to be very low (U.S. Fish and Wildlife Service 2014c), perhaps less than 300 adults (Spencer et al. 2011). During 2002–2009, Zielinski et al. (2013) could not detect a population trend, suggesting that the population may have been stable. Additionally, this small population occupies a linear-shaped area about 5–15 km (3–9 mi) wide along its length, making habitat fragmentation (e.g., from wildfire) a particularly critical issue (Spencer et al. 2011). Lastly, there is genetic evidence that indicates that fishers in California are genetically distinct (based on haplotypes) from all other groups (Knaus et al. 2011), and that the southern Sierra Nevada population contracted to its current, isolated distribution prior to European settlement (Tucker et al. 2012). The southern Sierra Nevada population currently is unlikely to be considered as a source population for reintroductions.

Washington

During the decades preceding the initiation of reintroduction efforts in 2008 in the Olympic Peninsula, fishers were believed to have been extirpated in Washington (Aubry and Houston 1992, Lewis and Stinson 1998). Fishers historically occurred throughout much of western Washington (e.g., Dalquest 1948, Aubry and Lewis 2003). Lewis and Stinson (1998:26) stated that, “Recovery of the fisher in Washington would probably not occur without reintroductions.” Following the development of a reintroduction feasibility assessment which indicated that the reintroduction of fishers could be successful in the Olympic Peninsula and the Cascades (Lewis and Hayes 2004), a recovery plan (Hayes and Lewis 2006), and an implementation plan for the reintroduction of fishers to Olympic National Park (Lewis 2006) were developed, after which Feasibility assessment for reintroduction of fishers in western Oregon, USA 28

reintroduction efforts for fishers began in Washington. During 2008–2010, 90 fishers from central British Columbia were released in Olympic National Park on the Olympic Peninsula of Washington and consequently monitored (Lewis 2014). A recent implementation plan for the reintroduction of fishers to the Washington Cascades (Lewis 2013) proposed the release of about 160 fishers total in two stages. The first stage includes releasing approximately 80 fishers in the southwestern portion of the Cascades recovery area, after which the second stage would involve the release of approximately 80 fishers in the northwestern portion of the Cascades recovery area. The Cascades reintroductions are scheduled to begin during fall 2015 (J. Lewis, Washington Department of Fish and Wildlife, personal communication). Given that reintroduction efforts have been implemented very recently and the current status of the reintroduced population is not well-understood, Washington currently cannot be considered as a source for fishers to reintroduce into western Oregon.

British Columbia, Canada

Fishers from British Columbia have been the source of numerous reintroduction efforts in the western U.S. for decades (e.g., Idaho [Jones 1991], Montana [Weckworth and Wright 1968], Oregon [Aubry and Lewis 2003], Washington [Lewis 2014]), and have been recommended as the source for future reintroductions in Oregon (Drew et al. 2003). An epidemic of mountain pine beetles (Dendroctonus ponderosae) has resulted in widespread mortality of overstory pines, and consequently salvage clearcuts of all trees in the affected areas, in British Columbia; this may in turn negatively affect fisher populations (Weir and Corbould 2010). The successful reintroduction of fishers in the southern Cascades of Oregon included individuals from British Columbia (Aubry and Lewis 2003). The well-established process used by several U.S. states to secure fishers from British Columbia, and the relatively close proximity and relatedness of fishers in British Columbia, make this province a primary candidate as a source for reintroductions in western Oregon. However, as previously mentioned, British Columbia is the source for fishers for reintroduction into Washington, so close coordination among agencies in British Columbia, Oregon, and Washington would be critical for obtaining fishers for reintroduction efforts in Oregon. This includes preventing a level of removal from source populations in British Columbia that would negatively affect those populations. Fishers in British Columbia are currently ranked as S2S3 on the Blue List, which puts them between imperiled and vulnerable within the province (British Columbia Conservation Data Centre 2015). Current rates of forest harvest in central British Columbia may complicate efforts to obtain fishers from that area for reintroductions; however, fisher populations from northeastern British Columbia may be able to support removals, although these are more genetically similar to fishers in Alberta (R. Weir, British Columbia Ministry of Environment, personal communication).

Alberta, Canada

Fishers are present in western and northern Alberta (Gibilisco 1994). Additional genetic analysis conducted by the Washington Department of Fish and Wildlife (Warheit 2004) suggested that fishers in western Alberta shared no common haplotypes with 3 samples (haplotypes 1 and 4) obtained from Washington. However, one sample from Washington included haplotype 6 (J. Lewis, Washington Department of Fish and Wildlife, personal communication), which is also found in western Alberta samples and which may have been derived from haplotype 4. As Feasibility assessment for reintroduction of fishers in western Oregon, USA 29

Oregon and Alberta do not seem to share any common haplotypes for fishers, if genetic similarity is a concern, Alberta may not be a suitable candidate as a source for fishers to reintroduce into Oregon.

Great Lakes Populations

Several Great Lakes states (e.g., Michigan, Minnesota, Wisconsin) have fisher populations. Increased harvest restrictions have recently been implemented in Michigan in response to declining fisher populations. Fisher populations in northern Wisconsin have decreased substantially during the past decade, but have increased in central Wisconsin during the same time period. Fishers in central Wisconsin are primarily on private lands, which may be a difficult situation to address from a source population perspective. At this time, state wildlife agencies in Michigan and Wisconsin are not able to consider providing fishers for reintroduction efforts in another state (A. Bump, Michigan Department of Natural Resources, personal communication; J. Olson, Wisconsin Department of Natural Resources, personal communication). Minnesota has served as a source population for several fisher reintroductions in the western U.S.. In fact, Minnesota has also served as a source population during reintroductions of fishers to Michigan and Wisconsin (see Williams et al. 2007). Minnesota may be able to provide fishers for future reintroduction efforts in other states (J. Erb, Minnesota Department of Natural Resources, personal communication). Minnesota served as one of the source populations for the successful reintroduction of fishers to the southern Cascades in Oregon, and although one haplotype (#10) in Minnesota occurs in the reintroduced population, it is not known to be present among indigenous fishers in southwestern Oregon (Aubry and Lewis 2003, Drew et al. 2003). As with Alberta, if genetic similarity is a concern, Minnesota may not be a suitable candidate as a source for fishers to reintroduce into Oregon.

POTENTIAL REINTRODUCTION THREATS

Potential threats to reintroduction success (i.e., re-establishment of a viable population) of fishers may be based on historical threats, i.e., the factors (if known) associated with population decline or extirpation in the area of interest, and factors that are potential threats under current conditions. Identifying and eliminating, minimizing, or adjusting for these threats are critical for reintroduction success (International Union for Conservation of Nature 2014).

Land Management Decisions

Federal

U.S. Forest Service.—The feasibility assessment area in western Oregon includes >3.7 million ha (>9.3 million ac) of U.S. Forest Service land (Table 2). National Forest management is directed by the Multiple-Use Sustained-Yield Act of 1960, as amended (16 U.S.C. §§ 528 et seq.) and the National Forest Management Act of 1976, as amended (90 Stat. 2949 et seq.; 16 U.S.C. §§ 1601 et seq.). The National Forest Management Act specifies that the Forest Service must have a Land and Resource Management Plan (LRMP) to guide and set standards for all natural resource management activities on each National Forest or National Grassland. The Feasibility assessment for reintroduction of fishers in western Oregon, USA 30

Forest Service has recently revised their National Forest Management Act planning rules (U.S. Forest Service 2012), which will apply to future LRMPs. Current LRMPs were developed under the 1982 planning rule (U.S. Forest Service 1982), which required the U.S. Forest Service to maintain viable populations of existing native and desired non-native vertebrate species in the planning area. The revised rule requires plans to use an ecosystem and species-specific approach to provide for the diversity of plant and animal communities and maintain the persistence of native species in the plan area. This would include contributing to the recovery of federal ESA- listed species, conserving proposed and candidate federal ESA species, and maintaining viable populations of species of conservation concern (U.S. Forest Service 2012). Directives for implementing this rule have not been finalized. While there is concern over the removal of the requirement to maintain viable populations of vertebrate species, and the increase in discretionary language compared to the previous rule (Schultz et al. 2013), the obligation to ensure that populations of native species persist remains in effect.

The U.S. Forest Service policy manual (U.S. Forest Service 2005) allows for designation of sensitive species of management concern. The fisher was previously identified as a sensitive species throughout the feasibility assessment area (U.S. Forest Service 2007, 2011, unpublished data) and would again be identified as such depending on the pending federal ESA listing decision. The Sensitive Species Policy is contained in the U.S. Forest Service Manual (U.S. Forest Service 2005: section 2670.32) and calls for National Forests to assist and coordinate with other federal agencies and states to conserve these species. Special consideration for the species is made during land-use planning and activity implementation to ensure species viability and to preclude population declines that could lead to a listing under the federal ESA (U.S. Forest Service 2005: section 2670.22). Additionally, programs and activities must be analyzed for their potential effect on sensitive species. If species viability is a concern, impacts are to be avoided or minimized; if impacts cannot be avoided, a further analysis of the significance of potential adverse effects is required; the action must not result in loss of species viability or create significant trends toward listing under the federal ESA (U.S. Forest Service 2005: section 2670.32). How sensitive species status protects fishers depends on LRMPs for individual forests, and on site-specific project analyses and implementation.

Bureau of Land Management.—Lands under management of the Bureau of Land Management (BLM) include >945,000 ha (>2.3 million ac) in the feasibility assessment area in western Oregon (Table 2), and management is directed by the Federal Land Policy and Management Act of 1976, as amended (FLPMA; 43 U.S.C. §§ 1704 et seq.). This legislation provides direction for resource planning and establishes that BLM lands shall be managed under the principles of multiple use and sustained yield. This law directs development and implementation of Resource Management Plans (RMPs), which guide management of BLM lands at the local level. The RMPs are the basis for all actions and authorizations involving BLM-administered lands and resources and may contain specific direction regarding fisher habitat, conservation, or management, but to date, none specifically address requirements for fishers. BLM lands are also managed under the Oregon and California Railroad and Coos Bay Wagon Road Grant Lands Act (O&C Lands Act of 1937, Public Law 75-405), which requires the agency to deliver a predictable supply of timber on a sustained yield basis.

Feasibility assessment for reintroduction of fishers in western Oregon, USA 31

Fishers are also designated as a sensitive species throughout the feasibility assessment area on BLM lands (Bureau of Land Management 2008a, 2010, unpublished data). The special status species policy contained in the BLM Manual (Bureau of Land Management 2008b:section 6840.02B) directs BLM to initiate conservation measures that reduce or eliminate threats and minimize the likelihood of listing under the federal ESA. RMPs must address sensitive species, while implementation-level planning should consider site-specific procedures needed to bring species and their habitats to the condition where sensitive species policies would no longer be necessary (Bureau of Land Management 2008b:section 6840.2A1B).

Protection afforded the fisher as a sensitive species on Forest Service and BLM lands largely depends on the management plan (LRMP or RMP) for the individual unit and on site-specific project analyses and implementation. In western Oregon, National Forests and BLM districts do not have fisher-specific standards and guidelines within their management plans.

Northwest Forest Plan.—The Northwest Forest Plan was adopted by the U.S. Forest Service and BLM in 1994 to guide the management of >9.7 million ha (>24 million ac) of federal lands in portions of western Washington and Oregon, and northwestern California within the range of the northern spotted owl (U.S. Forest Service and Bureau of Land Management 1994a,b). The Northwest Forest Plan amends the management plans of National Forests and BLM districts and is intended to provide the basis for conservation of the spotted owl and other late-successional and old-growth forest-associated species on federal lands. This plan is important for fishers because it created a network of late-successional and old-growth forest that currently provides fisher habitat, and the amount of habitat is expected to increase over time. The following descriptions of the Northwest Forest Plan land allocations and standards therefore define the existing regulations that guide forest management of fisher habitat in the referenced areas.

Of the 4.3 million ha (10.7 million ac) of Northwest Forest Plan lands in Oregon, 2.0 million ha (4.9 million ac) are within reserved land allocations (Congressionally Reserved Areas and Late Successional Reserves) and are managed to retain existing natural features or to protect and develop late-successional and old-growth forest ecosystems. There is approximately 1.4 million ha (3.4 million ac) of the Northwest Forest Plan area that is classified as matrix, where scheduled timber harvest is permitted (U.S. Forest Service and Bureau of Land Management. 1994b). Protections for occupied marbled murrelet sites, spotted owl sites, and other species also overlay matrix lands, further reducing the area available for timber harvest (U.S. Forest Service and Bureau of Land Management. 1994b). Riparian reserves overlay all land allocations and emphasize protection of riparian-dependent resources from a minimum of 30–91 m (100–300 ft) wide on each side of the stream, depending on the water body (U.S. Forest Service and Bureau of Land Management. 1994b). Timber harvest is restricted in riparian reserves to vegetation- management activities that are consistent with Aquatic Conservation Strategy objectives (U.S. Forest Service and Bureau of Land Management. 1994b). Although timber harvest is not programmed in Late Successional Reserves, vegetation management activities such as thinning and understory removal of vegetation may occur in this allocation to develop late-successional forests or to reduce the risk of large-scale stand-replacement disturbances; treatments must meet the objectives of conserving and developing late-successional conditions.

Feasibility assessment for reintroduction of fishers in western Oregon, USA 32

The annual volume of timber offered for sale in the entire three-state Northwest Forest Plan area has been greatly reduced since 1990, in part due to implementation of this plan. The annual probable sales quantity (PSQ or targeted timber volume) under the plan is just over 800 million board-feet, only 18% of the volume offered annually during the 1980s by federal agencies in the area included in this plan (Grinspoon and Phillips 2011). The actual effect has been less because actual harvested timber sales from inception of the plan through 2008 have averaged 469 million board-feet/year, or 58% of PSQ (E. Grinspoon, U.S. Forest Service, personal communication1). Thus, the threat of habitat loss from forest-management activities on federal lands within the area included in the Northwest Forest Plan has been substantially reduced.

Implementation of the Northwest Forest Plan is intended over time (about 100 years) to provide a network of large block reserves of late-successional forest habitat connected through riparian reserves surrounded by a matrix of younger, more intensively managed forest. As the forests within reserved land allocations mature, current habitat conditions for fishers are expected to improve on federal lands. In assessing the effects of the draft Northwest Forest Plan on fishers, the Forest Ecosystem Management Assessment Team (1993) projected a 63% likelihood of achieving an outcome in which habitat is of sufficient quality, distribution, and abundance to allow the fisher population to stabilize and be well distributed across federal lands. The team further concluded that there was a 37% likelihood that habitat was sufficient to allow fishers populations to stabilize, but that there would be significant gaps in the species distribution on federal lands and the ratings for fisher reflected a general “uncertainty about the future welfare of this species regardless of option” (Forest Ecosystem Management Assessment Team 1993:IV- 173). Additional mitigation measures were added to the final Northwest Forest Plan to increase the overall outcome for fishers (Appendix J2, p. J2–471). Measures such as specifying down wood amounts in matrix allocations, increasing riparian reserves, and retaining dispersed patches of late-successional forest all increased the likelihood ratings of fishers being well distributed across federal lands from 63% to >80% (U.S. Forest Service and Bureau of Land Management. 1994a). In conclusion, however, the species analysis team stated that due to cumulative effects, fisher populations are likely to “…continue to be rare and have disjunct distributions” (Appendix J2, p. J2–471).

Non-Northwest Forest Plan.—The Forest Service and BLM manage an additional 1.0 million ha (2.5 million ac) of land within the feasibility assessment area outside of the Northwest Forest Plan area (87% U.S. Forest Service, 13% BLM). These are those lands outside of the range of the northern spotted owl, and mainly comprise those areas east of the Cascade Range. Management in this area focuses on additional riparian and old-forest structure protections described in the PACFISH and INFISH strategies. Under the PACFISH strategy (U.S. Forest Service and Bureau of Land Management 1995), National Forests and BLM units with anadromous fish watersheds are required to provide riparian habitat conservation area buffers ranging from 15 to 90 m (50 to 300 ft) on either side of a stream, depending on the stream type and size. With limited exceptions, timber harvesting is generally not permitted in riparian habitat conservation areas (U.S. Forest Service and Bureau of Land Management 1995). Riparian protections similar to PACFISH were incorporated for those watersheds containing non-

1 Cited in U.S. Fish and Wildlife Service (2014c). Feasibility assessment for reintroduction of fishers in western Oregon, USA 33 anadromous fish species (INFISH) on National Forests outside of the Northwest Forest Plan and PACFISH strategies (U.S. Forest Service 1995a). The INFISH strategy does not apply to BLM lands. Finally, National Forests in Oregon that are outside of the Northwest Forest Plan also must provide additional protection of late and old-forest structure (U.S. Forest Service 1995b,c,d). Commonly referred to as eastside screens, this interim direction proclaims no net loss of late and old-structure habitat in areas with levels below historic range of variability (U.S. Forest Service 1995d). Very little of the area under any of these strategies occurs within the feasibility assessment area, and even less in areas occupied by fishers. However, the additional protection guidelines may provide refugia and connectivity among more substantive blocks of fisher habitat.

National Park Service.—Statutory direction for National Park Service lands in western Oregon is provided by provisions of the National Park Service Organic Act of 1916, as amended (16 U.S.C. §§ 1 et seq.) and the National Park Service General Authorities Act of 1970 (16 U.S.C. §§ 1a-1). Land management plans for the National Parks within the feasibility assessment area do not contain specific measures to protect fishers, but areas not developed specifically for recreation and camping are managed toward natural processes and species composition and are expected to maintain fisher habitat. Prescribed fire is often used as a habitat-management tool by the National Park Service. The effects of these burns on fishers are not known, but if key fisher habitat elements can be retained, fuels reduction through prescribed fire may benefit fishers in the long term by reducing the threat of fisher habitat loss from stand-replacing wildfires (Truex and Zielinski 2013, Zielinski 2014).

National Parks within the feasibility assessment area in western Oregon include only Crater Lake National Park (almost 74,000 ha [almost 183,000 ac]). In addition, the National Park Service manages other lands in western Oregon (e.g., Oregon Caves National Monument and Preserve). Relatively little high-quality habitat for fishers occurs within National Park Service lands in western Oregon (Table 2).

Tribal Governments

A variety of tribal governments exist in western Oregon, many of which own forest lands or have rights for management of lands not currently under tribal ownership (e.g., the Klamath Tribes). None of the tribes in Oregon specifically manage for fisher or fisher habitat on their lands.

The Warm Springs Indian Reservation is the largest block of Indian land in Oregon, at approximately 263,100 ha (650,000 ac), primarily in Jefferson and Wasco counties. Forest lands on the reservation comprise 178,100 ha (440,000 ac), with approximately 110,500 ha (273,000 ac) available for commercial timber harvest (Warm Springs 2013). The reservation is outside the known current fisher populations.

The Confederated Tribes of Siletz Indians manage approximately 5,900 ha (14,500 ac) of tribal forest in Lincoln and Douglas counties (Confederated Tribes of Siletz Indians 1999, 2010; M. Feasibility assessment for reintroduction of fishers in western Oregon, USA 34

Kennedy, Confederated Tribes of Siletz Indians, personal communication2). Most of this land is managed for commercial timber harvest, but almost 1,700 ha (4,300 ac) were recently acquired as compensation for injuries to marbled murrelets as a result of a 1999 oil spill from the freighter vessel M/V New Carissa. The Tribes have entered into a conservation easement wherein the property will be managed as habitat for the marbled murrelet, with habitat protections to be sustained even if the marbled murrelet no longer is afforded protection under the federal ESA. Existing habitat will be protected, while remaining property will be managed to move even-aged stands towards more diverse structure, providing for other late-successional forest species including the fisher (Confederated Tribes of Siletz Indians 2010). Maintaining this area as murrelet habitat may also be beneficial for fisher habitat because many of the forest structures and stand conditions found in murrelet habitat can benefit fishers by providing rest and den sites, although fishers are not known to occur in the area.

The former Klamath Indian Reservation is currently part of the Fremont-Winema National Forest. The Klamath Tribes and U.S. Forest Service have signed a memorandum of agreement describing the process for government-to-government relations regarding management of the former reservation (Klamath Tribes and U.S. Forest Service 2005). In the memorandum of agreement, the U.S. Forest Service agrees to incorporate the Tribes and Tribal policy and guidelines into their development of plans and natural-resource activities. Management activities proposed by the Klamath Tribes on the Fremont-Winema National Forest are generally consistent with the Northwest Forest Plan, and follow a Tribal plan to restore forests to structurally complex forests dominated by ponderosa pine and mixed-conifers (Johnson et al. 2008). Fishers have been observed on former reservation lands. Fishers are not explicitly managed for under the Northwest Forest Plan or by the Klamath Tribes, although restoration of structurally complex forests per the Tribe’s forest plan (Johnson et al. 2008) could be beneficial to fishers.

The Confederated Tribes of Grand Ronde manage approximately 10,000 ac (4,050 ha) of tribal forest in Yamhill County, Oregon, outside the known current fisher populations. The tribal forest is managed for commercial timber harvest (Confederated Tribes of the Grand Ronde 2012).

The Coquille Indian Tribe manages the 2,200-ha (5,400-ac) Coquille Forest located in Coos County, just north of the indigenous fisher population in southwestern Oregon. This land was formerly managed by the BLM (Coos Bay District) and is to be managed according to the standards and guidelines of the district’s final resource management plan, as amended by the Northwest Forest Plan (Coquille Indian Tribe 1998). Although the Coquille Forest is managed in accordance with the Northwest Forest Plan, the land allocations on the forest are matrix overlain by riparian reserves (Coquille Indian Tribe 1998). Consequently, the only habitat components provided for fishers are structural features provided by green tree, snag, and down wood retention requirements within the matrix, and protection provisions of the riparian reserves. In addition to the Coquille Forest, the Tribe manages another 405 ha (1,000 ac) of tribal trust lands on which operational forestry occurs (J. Robison, Coquille Indian Tribe, personal

2 Cited in U.S. Fish and Wildlife Service (2014c). Feasibility assessment for reintroduction of fishers in western Oregon, USA 35

communication3). While canopy cover suitable for fisher occupancy would likely not be maintained under the Tribe’s management, residual levels of resting structures and small patches of late-successional forest retention may facilitate fisher movements across the landscape between surrounding federal lands. No high-quality habitat for fishers was assigned within Coquille Tribal lands through modeling efforts by the U.S. Fish and Wildlife Service (2014c; Table 2).

State

Oregon Parks and Recreation Department.—State parks in Oregon comprise 45,000 ha (112,000 ac), much of which may provide forested habitats suitable for fishers. These parks are managed by the Oregon Parks and Recreation Department, with a mission to, “…provide and protect outstanding natural, scenic, cultural, historic, and recreational sites for the enjoyment and education of present and future generations” (Oregon Parks and Recreation Department 2014:1). Fisher habitat modeling indicates that >7% of state park land in western Oregon is high-quality habitat (Table 2). Most of the state parks are scattered and relatively small parcels that provide mainly recreational opportunities such as camping and picnicking, with little benefit to fishers. Some of the larger parks (e.g., Silver Falls at 3,600 ha [9,000 ac]) may provide areas of intact forest habitat that may provide suitable fisher habitat now or in the future.

The Oregon Forest Practice Administrative Rules (Oregon Administrative Rules Chapter 629, Division 600, as revised) and Forest Practices Act (Oregon Revised Statutes 527.610 to 527.770, 527.990[1], and 527.992) (Oregon Department of Forestry 2010a) apply to all non-federal and non-tribal lands in Oregon, regulating activities that are part of the commercial growing and harvesting of trees; this includes timber harvesting, road construction and maintenance, slash treatment, reforestation, and pesticide and fertilizer use. Oregon Administrative Rules provide additional guidelines intended for conserving soils, water, fish and wildlife habitat, and specific wildlife species while engaging in tree growing and harvesting activities, but these rules do not directly protect fishers or fisher habitat. Application of the rules may, however, retain some structural features (e.g., snags, green trees, down wood) that contribute to fisher habitat. For example, in regeneration harvest units >10 ha (>25 ac), operations must retain two snags or two green trees, and two downed logs per 0.4 ha (per 1 ac). Green trees must be >28 cm (>11 in) diameter-at-breast height and >9 m (>30 ft) in height, and down logs must be >1.8 m (>6 ft) long and >0.28 m3 (>10 ft3) in volume (Oregon Revised Statute 527.676). These residuals, however, are substantially smaller than those typically selected by fishers at resting sites (Aubry et al. 2013).

Prohibition of timber harvest within a maximum of 6 m (20 ft) of streams may provide some narrow, linear strips of older forests, which may contain some structural features of benefit to fishers. Additional retention of green trees (and in some cases hardwoods and snags) are required up to 30.5 m (100 ft) from the stream, depending on stream type, with amounts varying according to stream type and basal area within the 6.1-m (20-ft) no-cut stream buffer (Oregon Administrative Rules 629-640-0100 through 629-640-0400. In addition, retention buffers are

3 Cited in U.S. Fish and Wildlife Service (2014c). Feasibility assessment for reintroduction of fishers in western Oregon, USA 36

required on private lands around northern spotted owl nest sites (28 ha [70 ac] of suitable habitat) (Oregon Administrative Rule 629-665-0210), bald eagle (Haliaeetus leucocephalus) nest sites (100-m [330-ft] buffer) (Oregon Administrative Rule 629-665-0220), bald eagle roost sites (100- m [330-ft] buffer) (Oregon Administrative Rule 629-665-0230), and great blue heron (Ardea herodias) nest sites (91-m [300-ft] buffer) (Oregon Administrative Rule 629-665-0120). Also, foraging trees used by bald eagles (Oregon Administrative Rule 629-665-0240) and osprey (Pandion haliaetus) nest trees and associated key nest site trees (Oregon Administrative Rule 629-665-0110) are also protected from timber harvest. In all cases, protections of these sites are lifted when the site is no longer considered active (Oregon Administrative Rule 629-665-0010). These retention areas might provide some small pockets of mid- to late-successional habitat, and some old-forest structures that are desirable fisher habitat components may occur within these retention patches. However, with the exception of the no-cut riparian buffer, these are not intended to be retained long-term. Furthermore, these areas, at best, would only provide individual structures and small pockets of habitat in a landscape that is otherwise typically managed for industrial timber harvest with short rotations and limited opportunity to become suitable fisher habitat.

Oregon Department of Forestry.—There are approximately 332,300 ha (821,000 ac) of state forest lands within western Oregon that are managed by the Oregon Department of Forestry. These lands include small scattered parcels, but most occur within one of six state forests, the largest being the Tillamook State Forest at 147,300 ha (364,000 ac). Management of state forest lands are guided by forest management plans (Oregon Department of Forestry 1995; 2010b,c; 2011). The Oregon Department of Forestry has a species of concern policy for managing those species “…at risk due to factors such as declining populations, limited range, or low quality or quantity of habitat” (Oregon Department of Forestry 2010d:9). Only Oregon Department of Forestry districts in northwestern Oregon have identified their sensitive species to date, and fishers are not on these lists (Oregon Department of Forestry 2010d:10–11).

State forests in western Oregon are managed for specific amounts of forest structural stages. The objective is to develop 15–25% of the landscape into older forest structure (e.g., 81 cm [32 in] minimum diameter trees, multiple canopy layers, diverse structural features, and diverse understory) and 15–25% into layered structure (e.g., two canopy layers, diverse multi-species shrub layering, and >46 cm [>18 in] diameter trees mixed with younger trees) over the long term (Oregon Department of Forestry, No Date). State forests in northwestern Oregon currently have 6% of their land base in the layered and older forest structure categories, combined (Oregon Department of Forestry, No Date). The U.S. Fish and Wildlife (2014c) fisher habitat model indicates that 36% of state forest land currently provides high-quality fisher habitat (Table 2). Managing for the structural habitats as described should increase habitat for fishers on state forests.

Management plans for Oregon’s state forests do not provide specific provisions for conserving the fisher or its habitat, although management for other species and resources may provide retention of some fisher habitat elements and patches of fisher habitat. Examples include 400 to 2,400 ha-units (1,000 to 6,000 ac-units) of anchor habitats designed to benefit species associated with older forest and interior habitat conditions in the short term, allowing them to persist and re- colonize new habitat created on the landscape over time (Oregon Department of Forestry 2010b; Feasibility assessment for reintroduction of fishers in western Oregon, USA 37

L. Dent, Oregon Department of Forestry, personal communication4). Spotted owl nest sites are protected by a 100-ha (250-ac) core, maintenance of 202 ha (500 ac) of suitable habitat within 1.1 km (0.7 mi) of the nest, and 40% of habitat within the provincial home range (ranging from 1.9 to 2.4 km [1.2 to 1.5 mi] radius of the nest, depending on in which physiographic province the nest is located) (Oregon Department of Forestry 2008, 2010e). Marbled murrelet management areas (MMMAs) are established around marbled murrelet occupied sites (Oregon Department of Forestry 2010f). Management activities within MMMAs need to maintain habitat suitable for nesting and minimize disturbance of reproductive activities (Oregon Department of Forestry 2010g). Sizes of MMMAs vary with local conditions and habitat. In the northern Coast Range, MMMAs total 2,542 ha (6,281 ac), averaging 61 ha (150 ac) in size (J. Weikel, Oregon Department of Forestry, personal communication5). In the south-central Coast Range on the Elliott State Forest, 1,370 ha (3,385 ac) of MMMAs are designated, with an additional 4,375 ha (10,811 ac) that overlap designated spotted owl protection areas (L. Dent, affiliation Oregon Department of Forestry, personal communication5). Many of these retention blocks are not large enough to support a fisher home range, but they may provide habitat patches that allow fisher movements across the landscape.

Retention of green trees and snags within harvest units differs among state forests, ranging from 4.9 to 9.9 live trees/ha (2 to 4 live trees/ac) on the Elliott State Forest to landscape-level targets of 12.4 trees/ha (5 trees/ac) and 4.9 snags/ha (2 snags/ac) (L. Dent, affiliation Oregon Department of Forestry, personal communication4). Riparian buffers include a 7.6-m (25-ft) no- cut area, with varying tree retention requirements out to 30 to 52 m (100 or 170 ft), depending on stream size, use, and whether fish are present (Oregon Department of Forestry 2010b; L. Dent, Oregon Department of Forestry, personal communication5). These sites would not meet fisher habitat requirements post-harvest due to reduced stand densities and lack of crown continuity (e.g., Oregon Department of Forestry 2010c). However, the retained trees would contribute to the development of the older forest and layered structural stages that the state is working to develop which may provide habitat for fishers in the future.

Climate Change and Wildfires

Projections of climate change over the next century throughout the geographic distribution of fishers generally include increases in both temperature and precipitation, which may result in a northward expansion and southward contraction in fisher distribution (Lawler et al. 2012). Concomitant with climate change, both the frequency and duration of large wildfires and the length of the wildfire season have been increasing in the western U.S. during the past three decades (Westerling et al. 2006). In Oregon, the average number of wildfires that burn >400 ha (>1,000 ac) annually has doubled, and spring and summer temperatures have increased on average 0.11 °C/decade (0.19 °F/decade) and 0.17 °C/decade (0.30 °F/decade), respectively, since the 1970s (Climate Central 2012). Areas with historically higher severity fire regimes, complex topography, and greater continuity of fuels may be affected more by predicted increases of wildfires than other areas (Cansler and McKenzie 2014). Fire has the potential to cause

4 Cited in U.S. Fish and Wildlife Service (2014c).

Feasibility assessment for reintroduction of fishers in western Oregon, USA 38

landscape changes at large spatial scales that could decrease the amount and quality of habitat, fragment its distribution, or convert it to non-suitable land-cover types for fishers (and other wildlife species).

Descriptions of fisher habitat include dense and structurally complex mid- to late-seral forests (e.g., Buskirk and Powell 1994, Raley et al. 2012). Forests with these characteristics are vulnerable in the event of a large fire, but variations in the range of habitat conditions in a given stand may also affect time to recovery following fire (Thompson et al. 2011). Fuels treatments to reduce risks associated with large, stand-replacement fires are dependent on site conditions and such prescriptions may have multiple goals, which could include ecosystem restoration, species conservation, public safety, and reduced risk of property losses. Although outcomes are difficult to project, the positive effects of fuels treatments (i.e., reduced risk of large wildfires that cause habitat loss) may outweigh the negative effects (e.g., decreased habitat quality) for fishers (Scheller et al. 2011). This is particularly true if adequate resting and denning structures are retained and forest composition and configuration across the landscape continue to meet habitat requirements for fishers (Thompson et al. 2011, Zielinski et al. 2014). Western Oregon generally is considered to be in a low fire-danger class based on weather characteristics (e.g., temperature, humidity, precipitation), properties of fuels (e.g., live or dead fuels, moisture content), and other factors (Bradshaw et al. 1983, U.S. Forest Service 2014). Therefore, the potentially negative effects of wildfire may be much lower for western Oregon than the western U.S. in general, and certain aspects of climate change may result in a long-term northward range shift for fishers. To minimize potential negative effects of wildfire during reintroduction efforts of fishers in western Oregon, selection of specific release sites could incorporate information on the relative risk of wildfire in western Oregon based on fire suitability models. Additionally, monitoring populations in areas that experience post-reintroduction wildfires will provide information on how fishers respond to these large-scale perturbations in western Oregon and aid in any future reintroduction efforts.

Vehicle collisions

Radiomarked animals allow for assessments of cause-specific mortality, although frequent monitoring increases the ability to accurately assess such causes by minimizing loss of evidence through post-mortality scavenging. Mortalities that result from vehicle collisions often relate to factors such as animal behavior, traffic volumes and speeds, road densities, and for recently translocated individuals, perhaps unfamiliarity with the area, within the animal’s home range. Davis et al. (2007) found that fishers were associated with paved roads, but also speculated that this result might have been confounded by road locations near waterways and high-value timber stands at elevations typical for fishers. Mortalities of fishers associated with vehicle collisions were 4% of total mortalities in a heavily harvested population in Maine (Krohn et al. 1994). In eastern Ontario, Koen et al. (2007) reported that <11% of radiomarked fishers were killed in vehicle collisions, although they pooled this cause with ≥1 other anthropogenic cause of mortality. In the southern Cascades of Oregon (reintroduced population), paved county roads did not seem to influence fisher home-range selection and no mortalities of radiomarked fishers were attributed to vehicle collisions (Aubry and Raley 2006). Vehicle collisions on paved roads accounted for 20% of mortalities of fishers reintroduced in the Olympic Peninsula of Washington (Lewis 2014). This was identified as an important source of mortality, but also Feasibility assessment for reintroduction of fishers in western Oregon, USA 39

seemed linked to a highway (U.S. Highway 101) in the interior of the study area and within large expanses of high-quality fisher habitat. In general, other than major highways, roads would not seem to present a substantial risk for fishers reintroduced into western Oregon. However, selection of release areas to minimize density of paved roads and with low traffic volumes would reduce this mortality risk.

Incidental Harvest

In areas with human access where harvest occurs, fishers are generally considered vulnerable to unsustainable harvest, at least at local scales, if appropriate regulatory mechanisms are not in place (e.g., Powell 1979, Strickland 1994). Regulatory adjustments have been implemented to prevent unsustainable harvest (e.g., Michigan [Hiller et al. 2011]). In areas where harvest of fishers is legal, juveniles seem to have the greatest vulnerability to harvest, whereas adult females seem to have the lowest (e.g., Douglas and Strickland 1987, Krohn et al. 1994, Strickland 1994). The loss of adult females in a recently reintroduced population would be very undesirable. There has been no harvest season open for fishers in Oregon since 1946 (Aubry and Lewis 2003).

Incidental capture of fishers in Oregon is rare (5 known since 1975, with 2 resulting in mortality; described in U.S. Fish and Wildlife Service 2014c). In annual game reports during 1946–1989, ODFW made no mention of any incidental captures of fishers, but brief descriptions of reintroduction efforts and potential sightings were included (e.g., Oregon State Game Commission 1951, 1961). Incidental harvest of one other mustelid, the wolverine, was occasionally mentioned in these reports, so it is unclear whether incidental harvest did not occur for fishers because of low populations (or other reasons) or whether incidental harvest occurred but simply was not reported.

Aubry and Raley (2006) reported that 2 fishers were incidentally captured by trappers in the northern Siskiyou Mountains (indigenous population) of Oregon. This source was not cited in the descriptions of incidental captures in U.S. Fish and Wildlife (2014c), so these 2 individuals may not have been included in the known incidental captures previously described. During the past decade, no other incidental captures are known to have been reported to either ODFW (S. Niemela, Oregon Department of Fish and Wildlife, personal communication) or to U.S. Forest Service (D. Clayton, personal communication) for either of the two extant fisher populations in Oregon. In northern California, incidental captures of fishers (n = 72) occurred during regulated trapping for bobcats, gray foxes, and raccoons at a rate of about 0.001 fisher/trap-night from a sample of 5 trappers over a cumulative total of 42 seasons (Lewis and Zielinski 1996).

Most types of traps (e.g., rotating-jaw traps, foothold traps, cable-restraints, snares) have become prohibited in California (since 1998) and Washington (since 2000) through ballot initiatives, whereas trapping regulations in Oregon are more consistent with the majority of U.S. states (see Association of Fish and Wildlife Agencies 2007). In Oregon, training and testing in the form of trapper education are required for applicants of trapping licenses in order to minimize the potential take of non-target species, such as fishers (ODFW 2014c). Trapping is typically allowed on most reservations and tribal lands, but is usually restricted to tribal members. Whereas a few tribal governments utilize existing state trapping regulations, most have enacted Feasibility assessment for reintroduction of fishers in western Oregon, USA 40

trapping regulations under their respective tribal codes. However, trapping activities are not known to be common on tribal lands.

Low rates of incidental capture in previous studies and coordination of reintroduction efforts with the Oregon Trappers Association should minimize potential risks associated with incidental capture of fishers reintroduced in western Oregon. To further reduce these low incidental capture rates, release areas with low road densities should be selected because of reduced access by trappers. The development of educational materials to help trappers avoid incidental take of protected species during regulated harvest activities have been completed for Canada lynx (Golden and Krause 2003) and wolverines (Hiller and White 2013) and could also be completed for fishers (see British Columbia Ministry of Forest, Lands, and Natural Resource Operations 2014:93 for brief example). Regulatory adjustments may also be a consideration in select areas during initial reintroduction efforts should incidental harvest become a concern. Although the concern for incidental captures of fishers is low, several options exist that may be implemented to further reduce risks.

Anticoagulant Rodenticides

Anticoagulant rodenticides have been identified as a threat to fishers in the western U.S. (U.S. Fish and Wildlife Service 2014a). For most of the west coast populations, illegal marijuana cultivation sites on public lands are implicated as the main source of these toxicants (U.S. Fish and Wildlife Service 2014c). On the Olympic Peninsula where some fisher home ranges overlap the edges of urban areas, legal uses around existing structures may also be a source. However, during 2013–2014, only 1 of 5 fishers either born or existing in that area for >4 years showed exposure to anticoagulant rodenticide during necropsy; that fisher’s home range included low- density housing and commercial development (P. Happe, National Park Service, personal communication). A recent analysis of fisher translocation efforts identified the number of breeding-age females and the number of large, dominant males released as predictors of reintroduction success (Lewis et al. 2012). Yet animals in these two life-history categories may be disproportionally impacted by exposure to toxins associated with cultivation sites, as described below. Furthermore, translocated animals typically experience high mortality rates and any anthropogenic factor inflating mortality rates could increase the risk of reintroduction failure. Ingestion of rodenticides may occur through the consumption of poisoned rodents or insects, scavenging of other poisoned animals, or the direct consumption of rodenticide which is often flavored with bacon, cheese, or peanut butter-based baits (Gabriel et al. 2012a).

Evidence from field projects in the Sierra Nevada region of California indicates that nearly all direct mortality from anticoagulant rodenticides associated with marijuana cultivation sites occurs during the spring. Of 12 fishers documented to have died from rodenticide poisoning statewide, 10 occurred during the denning season between March and June (M. Gabriel, Integral Ecology Research Center, personal communication). During this period, growers use large amounts of rodenticides to protect young marijuana plants from ground squirrels and other rodents. At the same time, adult female fishers are raising young and are under substantial physiological and nutritional stress. The loss of a single adult female causes the loss of an entire litter, but even if the female survives, anticoagulant rodenticide compounds can also be transferred to dependent kits through lactation (Gabriel et al. 2012a). Spring is also a period of Feasibility assessment for reintroduction of fishers in western Oregon, USA 41

highly variable weather conditions, and exposure to sublethal doses of pesticides has been shown to reduce an animal’s capacity for thermoregulation (Grue et al. 1991). This may be particularly critical for young kits exposed through lactation; as mothers are required to leave the den and forage, fisher kits may be exposed to more variable temperature fluctuations (Paragi et al. 1994).

It has also been shown that the more likely a fisher is to encounter a cultivation site, the more likely the animal is to die (Thompson et al. 2014). While this is a correlative relationship, it strongly suggests that wide-ranging animals are at greater risk of encountering a cultivation site and either consuming contaminated prey or consuming baited toxins directly. Dominant male fishers, while desirable translocation candidates, also range widely in the spring in search of mating opportunities. On the Hoopa Reservation in northern California, marijuana cultivation was directly implicated in 35% of male fisher mortalities (M. Higley, Hoopa Tribal Forestry, personal communication). Furthermore, evidence from fisher translocations in California and Washington indicate that all translocated animals can be expected to range widely in search of suitable habitat and home ranges, increasing their likelihood of encountering an illegal marijuana cultivation site.

Possibly more insidious than direct mortality is the probability that exposure to sublethal doses of rodenticides or insecticides can inflate supposedly natural causes of mortality. Exposure to organophosphate pesticides has been shown to reduce the immune response and increase an animal’s susceptibility to infection or disease (Vidal et al. 2009, Zabrodskii et al. 2012). Sublethal exposure to anticoagulant rodenticides has also been repeatedly linked to the likelihood that an animal will be unable to recover from the type of physical injury associated with predation activities, either minor wounds inflicted by prey or more substantial wounds incurred while escaping predators (Townsend et al. 1984, Erickson and Urban 2004). Finally, exposure to pesticides has been directly linked to an increased risk of predation (Cooke 1971, Farr 1977, Hunt et al. 1992). Taken together, the likely inflation of natural mortality plus the added direct mortality represent substantial risk to a tenuous, wide-ranging, translocated fisher population.

Whether these factors pose a significant risk to fishers reintroduced into Oregon may depend upon the location of proposed release sites. Due to variation in growing conditions, illegal marijuana cultivation appears to be more prevalent in southern Oregon than elsewhere in western Oregon, as detections of these illegal cultivation sites decrease northward (Fig. 11). It is not known at this time how the recent legalization of marijuana in Oregon (Ballot Measure 19) may affect the presence and distribution of illegal cultivation sites.

Risks of Small Populations

Due to financial and logistical constraints, founder populations for reintroductions typically are small in comparison to most established populations. These small populations are vulnerable to several environmental (e.g., food availability, weather) and demographic (e.g., birth rate, death rate, sex ratio) factors that can increase the risk of extinction, and therefore, reintroduction failure (Haig and Wagner 2001, van Wieren 2012). Loss of even a few individuals during initial periods of reintroductions can have major consequences for establishing populations. Similarly, small isolated populations of fishers that have persisted over time are also subject to similar risks (e.g., fishers in the southern Sierra Nevada, California; Tucker et al. 2012). Fishers in the Pacific Feasibility assessment for reintroduction of fishers in western Oregon, USA 42

coastal region have high levels of genetic structuring, indicative of limited gene flow and population isolation and therefore at higher risk of extinction (Wisely et al. 2004).

Inbreeding depression can occur in small populations from related individuals and can negatively affect fitness through accumulation of deleterious alleles and decreased heterozygosity, with expression of deleterious recessives at a higher-than-expected rate. One option to address the expression of deleterious alleles is the introduction of new genes into that small population, such as through population augmentation, described as genetic rescue (Weeks et al. 2011).

Random genetic drift may be caused through a founder effect, whereby a small number of colonizing individuals breed and the resulting population has different allelic frequencies from which the founders originated. One potential solution to inbreeding depression in small populations is the introduction of individuals from another population to increase genetic variation. Conversely, adaptation to local conditions may be difficult if the source population is from a distant area and adapted for different environmental conditions. However, it is also possible for genetically diverse individuals to avoid potential inbreeding and result in highly successful reintroductions (e.g., river otters; Mowry et al. 2014). Whether fishers are locally adapted or whether conditions (e.g., timber harvest, human development, predator communities) changed in Oregon to become more favorable for fishers from other, perhaps more developed, regions (Roy 1991, Drew et al. 2003) are unknown, but may partially explain the successful reintroduction of fishers with non-native haplotypes in southwestern Oregon. Consideration of how founders may affect the genetic and demographic stability of new populations should occur during the planning stages for reintroductions (Haig and Wagner 2001).

In addition to other factors mentioned in other sections of this assessment, successfully establishing a reintroduced population of fishers is also dependent on selection of unrelated individuals within the source population and selection of release areas to allow for increased connectivity and distributional increase of those populations (e.g., Haig and Wagner 2001, Mills et al. 2003). Selecting unrelated individuals based on a genetic assessment may not always be pragmatic. Selection of individuals over a large area within the source population and assuming low levels of relatedness may be a feasible alternative.

Pathogens and Parasites

Despite relatively few studies that focused on pathogens and parasites of fishers, this species is known to have shown exposure and susceptibility to canine distemper virus (Keller et al. 2012), rabies viruses (Larkin et al. 2010), toxoplasmosis (Larkin et al. 2011), and parvoviruses (Gabriel et al. 2012b), which are also associated with other mammalian carnivores. Although it is thought that diseases generally are not a primary source of mortality for fishers (e.g., Lewis and Hayes 2004), their potential effect, especially in combination with other factors (e.g., synergistic effects of ≥1 disease, exposure to toxins), may be of conservation concern for small insular populations, including reintroduced populations (see Gabriel et al 2012b). Gabriel et al. (2012b) offered several suggestions designed to reduce disease-associated risk to reintroduced fishers. These included disease-screening of the carnivore community at proposed release sites during the planning stages, for all founder animals, and potentially during any post-release recapture events. Also, disinfection protocols should be established and followed for all capture, handling, and Feasibility assessment for reintroduction of fishers in western Oregon, USA 43 transportation processes, and facilities and equipment. Finally, potential pre-release vaccinations should be considered and necropsy of all mortalities should be conducted by a wildlife pathologist, if possible.

During 2010, at least 10 gray foxes (Urocyon cinereoargenteus) and 1 coyote (Canis latrans) tested positive for rabies in a localized area in Josephine County in southwestern Oregon (Hiller 2011). Exposure of sympatric fishers to rabies during that time period was unknown, but this highlights the importance of disease-screening of carnivore communities at proposed release sites, even if sampled opportunistically.

LEGAL AND REGULATORY REQUIREMENTS

All State of Oregon and federal regulations must be followed and approvals obtained from the relevant agencies prior to any reintroduction efforts. If the proposed federal rule to list the fisher in all or part of its western coastal range results in listing in western Oregon, reintroduction efforts would be a cooperative venture between the U.S. Fish and Wildlife Service and ODFW. If the proposed federal listing does not include Oregon, management authority remains with ODFW; however, certain circumstances (described below) would require federal involvement.

State

The importation and release of live fishers into Oregon may be administered under the authority of ODFW and the Oregon Department of Agriculture (Oregon Administrative Rules 603-011- 0255 and 603-011-0382; see Oregon Department of Agriculture 2013). The party requesting importation and release of endemic wildlife in Oregon must obtain approval from the ODFW Wildlife Division Administrator and relevant field staff and secure an import permit number from the Oregon Department of Agriculture’s State Veterinarian. A Certificate of Veterinary Inspection must be conducted by a federally accredited veterinarian or agency wildlife veterinarian, must include the import permit number provided by the receiving state Department of Agriculture State Veterinarian, and must accompany the animals from the state or province of origin. Staff from ODFW will initiate the agency translocation communication and protocols through ODFW’s Wildlife Translocation Approval Forms (Forms A and B) for Intrastate Import or Export of Live Wildlife.

Federal

As proposed, the West Coast DPS in the proposed federal listing for fishers includes western Washington, western Oregon, and northwestern California south through the Sierra Nevada Range (U.S. Fish and Wildlife Service 2014a; Fig. 3). In Oregon, the proposed West Coast DPS generally encompasses the area from the Pacific coast east to and including the Cascade Range (Fig. 1). Because this DPS is currently a proposal for listing, its boundary may change with any final listing rule. No federal ESA permits for the reintroduced animals would be required while the species is proposed for listing. Furthermore, fishers are not currently listed under the federal ESA in any potential source populations. Any federal ESA requirements described below would only apply to fishers within the final, as yet undetermined, West Coast DPS boundary, should the Feasibility assessment for reintroduction of fishers in western Oregon, USA 44 population become listed. Additional federal ESA requirements include the assessment of fisher reintroductions on other listed species (see below).

Translocations of species listed under the federal ESA will require a permit from the U.S. Fish and Wildlife Service Division of Management Authority per Section 10(a)(1)(A) of the Act. In the case of reintroductions of fishers in Oregon, either of two conditions would require a permit: 1) obtaining fishers from a source population that was listed under the federal ESA; or 2) reintroducing fishers into the listed DPS, regardless of whether the source population was listed under the federal ESA. Fishers obtained from a population that is not listed under the federal ESA and reintroduced into an area outside of any established DPS would not require a federal ESA permit.

If fishers will be brought in from another country, in this case Canada, no U.S. permits are required; however, Wildlife Declaration Form 3-177 must be completed and presented to U.S. wildlife inspectors at the port of entry into the U.S. Importing wildlife is limited to specific ports, and coordination with the Fish and Wildlife Service Office of Law Enforcement should occur well in advance of import.

Regardless of the outcome of the proposed federal ESA listing, if reintroduction is authorized, funded, or carried out by any federal agency, or occurs on federal lands, the U.S. Fish and Wildlife Service will need to assess the effects of the action on other listed species through Section 7 of the ESA. For example, the U.S. Fish and Wildlife Service must determine whether reintroducing fishers into a specific area will affect other listed species and if so, whether it will jeopardize the continued existence of those species. Thus, a biological opinion completed under Section 7(a)(2) of the federal ESA will be required prior to the translocation if it is determined that fisher reintroductions may affect listed species.

Actions authorized, funded, or carried out by the federal government are also subject to the National Environmental Policy Act (NEPA). With respect to fisher reintroductions, this would include, but not necessarily be limited to: 1) issuance of any federal ESA permit; 2) federal funding of the translocation effort; 3) removing fishers from federal lands; or 4) putting fishers onto federal lands. Agencies are required by NEPA to assess the environmental impacts of actions under their jurisdiction. Most federal ESA Section 10(a)(1)(A) permits have met the requirements of NEPA by falling under a categorical exclusion wherein it has already been determined that actions under these permits do not have a significant effect on environmental quality; however, larger and potentially more controversial projects like fisher translocations could require further environmental analysis under NEPA before permit issuance. Actions involving federal ownership may require an Environmental Assessment to determine whether the action had a significant impact on the environment, providing the action wasn’t already covered under a NEPA categorical exclusion. Actions that have a significant impact would require completion of an Environmental Impact Statement before proceeding. For example, prior to reintroduction efforts in Washington, the National Park Service (2007) completed an Environmental Assessment for Olympic National Park.

If fishers are listed under the federal ESA in the area of reintroduction, taking of those animals would be federally prohibited, although exemptions for certain kinds of take are allowed. Taking Feasibility assessment for reintroduction of fishers in western Oregon, USA 45

that is incidental to and not the purpose of an otherwise lawful activity can be permitted by the U.S. Fish and Wildlife Service, although different conditions apply for federal and non-federal lands. Some management flexibility or regulatory assurances can be provided to landowners who have agreements with the U.S. Fish and Wildlife Service, such as Safe Harbor Agreements or Candidate Conservation Agreements. Currently, no such agreements exist for fishers in Oregon, but could be developed prior to any reintroductions. Also, the U.S. Fish and Wildlife Service could designate a reintroduced population as a non-essential experimental population, which would remove any federal ESA take prohibitions from that population and reduce the regulatory burden of the receiving landowner.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) ensures that international trade in plants and animals does not threaten their survival. The fisher is not listed in any CITES appendices and therefore does not require additional permitting as part of implementing CITES.

NECESSARY ELEMENTS

The reintroduction of fishers in western Oregon requires several elements that are critical for successful population re-establishment (e.g., Griffith et al. 1989, International Union for Conservation of Nature 2014). Prior to reintroduction efforts, surveys should be conducted in areas not previously surveyed during the past 20 years to determine if any unknown fisher population exits. Surveys conducted to detect presence of populations, as opposed to dispersing individuals, would be much more useful for decisions related to selection of reintroduction areas. Surveys could focus on areas containing high-quality habitat (e.g., northern Coast Range, northern Cascades; Figs. 3 and 6) and that may be potential reintroduction areas to prevent release of fishers into an area already containing a population. New funding and close coordination among state and federal agencies would be necessary to meet these objectives in most areas of interest in western Oregon.

Lewis et al. (2012) determined that two factors were positively associated with reintroduction success for fishers (number of females released, number of males released) and that one factor was negatively associated with reintroduction success (distance between source population and reintroduction area). Within financial and logistical constraints, these three factors can be controlled. If all other factors are held constant, the probability of reintroduction success should increase with an increasing number of fishers released, including transitioning from population establishment to persistence. The best sex-age composition of founder animals for a successful fisher reintroduction is female- (55–60%) and adult-biased (Lewis et al. 2012). Reintroduced fishers obtained from source populations in close proximity to release sites may be better adapted to conditions at the release site, thereby increasing the probability of re-establishing a viable population. However, strict adherence to this approach may be overly conservative in some situations, such as when this would result in severely limiting translocation options or when the potential for increased vigor from mixed populations would address the current loss of local adaption by a small population, particularly under rapidly changing environmental conditions (Weeks et al. 2011).

Feasibility assessment for reintroduction of fishers in western Oregon, USA 46

Lewis et al. (2012) also found an effect based on region, with translocations of fishers more successful in eastern versus western North America. Region is typically a factor that cannot be controlled, but regional differences in land cover and wildlife communities may at least partially explain this variation. For example, the mesopredator release hypothesis has been used to explain the disparity in range expansions (since most contracted range) between fisher populations in the western U.S. and those in the eastern and central U.S., with the latter two regions associated with reduced large carnivore communities (LaPoint et al. 2015). However, reintroduction projects often have constraints that affect maximizing the probability of population viability, including minimizing project costs, maximizing positive relationships with stakeholders and the public, so clearly trade-offs exist in many situations (Converse et al. 2013).

Financial and logistical constraints may limit the number of fishers available for reintroduction efforts. However, to be successful, such efforts require suitable levels of funding and the flexibility to adjust to changing conditions. The length of time over which reintroduction efforts occur is associated with reintroduction success (Griffith et al. 1989), but increasing the duration of efforts requires additional of funding. To maximize project success during a multi-year project, planning should include the possibility that funding in later years may be at reduced levels, or perhaps even become unavailable due to unforeseen circumstances.

Funding levels must also be appropriate to allow for long-term monitoring (e.g., resource selection, space use, survival, reproduction) and assessment of reintroduced fisher populations. For example, monitoring is a necessary element for assessing the extent to which management objectives have been achieved. The duration and intensity of post-release monitoring efforts should be consistent with the goals of reintroduction efforts to assess uncertainty and risk, but also to assess whether project goals and expectations are being met (International Union for Conservation of Nature 2014). Monitoring allows for progressive improvements in understanding and that information can be applied in an adaptive management approach to help ensure project success by reducing uncertainty during decision making (e.g., Williams and Brown 2012).

For reintroduced fishers, monitoring can include pre- and post-release disease-screening efforts (see Pathogens and Parasites section). Monitoring efforts more typically include data collection on radiomarked animals, capture efforts to mark new individuals as the project progresses, and capture efforts to re-mark individuals (i.e., to replace radiomarks), if possible. Data collection should be rigorous (Griffith et al. 1989) to assess project progress and, if necessary, protocols may be adapted accordingly. Data collected from radiomarked fishers includes survival, cause- specific mortality, reproductive success, den and resting-site locations and structures, dispersal movements and barriers, diet analysis through scat collection at den sites, habitat use and connectivity, and changes in spatial distribution of reintroduced populations. For example, prior to establishing home ranges, movements of translocated fishers may be considerable (Weir and Harestad 1997, Lewis 2014). Juvenile dispersal in lightly harvested populations in Massachusetts included distances ≤100 km (60 mi) (York 1996), although dispersal may be male-biased in non-harvested populations (Aubry et al. 2004). Resources must be in place to allow for monitoring individuals that disperse long distances and across multiple land ownerships from release areas. Ecological monitoring at release sites, for example of certain species of concern (e.g., martens, murrelets) and for potential predators (e.g., bobcats), may also Feasibility assessment for reintroduction of fishers in western Oregon, USA 47

be beneficial for assessing potential ecological consequences of reintroductions and selection of future release areas.

Consideration of animal welfare is another necessary element for planning and implementing a reintroduction (Harrington et al. 2013). In addition to meeting state and federal regulatory requirements, capture, handling, holding, and health assessment of fishers from the source population should follow established protocols (e.g., Association of Zoos and Aquariums 2010, Sikes et al. 2011, Gabriel et al. 2012b). Monitoring and research activities must also follow established guidelines (e.g., Sikes et al. 2011) and if relevant, approval through appropriate committees (e.g., Institutional Animal Care and Use Committee). Consideration of how fishers are released is also important. Whether a release of reintroduced individuals was classified as hard (i.e., no food or shelter provided at release site) or soft (e.g., food or shelter provided at release site, delayed release at sites; intended to increase probability of survival) did not seem to influence reintroduction success for fishers (Lewis et al. 2012) or for a suite of other avian and mammalian species (Griffith et al. 1989).

Identification of groups and individuals that may be affected by potential reintroductions is another element necessary to ensure reintroduction success. These groups should be considered for inclusion in the planning process, including addressing any pre-reintroduction concerns and post-reintroduction issues or conflicts that may arise (International Union for Conservation of Nature 2014). Planning activities should be designed to develop trust and understanding, minimize potential conflicts or surprises, and integrate stakeholders into the process. Information on processes and procedures should be shared with groups, including any state and federal legal and regulatory requirements and how affected groups can meet any such requirements with state and federal logistical assistance. Project updates should be consistently provided, especially during milestone activities such as release events, to stakeholders and other interested groups. Dissemination of information through project collaborators via web sites, social networks, and other media outlets should be designed to reach target audiences. For the scientific community, publication of results in peer-reviewed scientific outlets is critical to increase scientific understanding and to document and evaluate the process such that it may be used with success in other applications.

Any translocation should yield a measurable conservation benefit to the population, the species, or an ecosystem (International Union for Conservation of Nature 2014). A structured process from planning to project completion is often beneficial, especially for large research and management projects. An adaptive management approach (e.g., Williams and Brown 2012) may be implemented to reduce uncertainty as the reintroduction process proceeds by using an objective step-wise framework (e.g., translocations on an annual basis, translocations in subsequent and unoccupied areas). Similarly, decision trees have been developed for reintroduction processes (e.g., Harrington et al. 2013) and may be adapted for species-specific projects. Such approaches include documentation of the process, which will allow for evaluation of progress, assessment of whether objectives are being met, and justification should management objectives need revision (International Union for Conservation of Nature 2014).

Feasibility assessment for reintroduction of fishers in western Oregon, USA 48

POTENTIAL STAKEHOLDERS AND COOPERATORS

At the time of this writing, management of fishers in Oregon falls under the authority of the Oregon Department of Fish and Wildlife. However, the U.S. Fish and Wildlife Service has proposed to list the proposed West Coast DPS of fishers as threatened under the federal ESA, and would be a necessary cooperator should listing occur. Regardless of whether the fisher becomes listed under the federal ESA, the Oregon Department of Fish and Wildlife will be a critical agency while developing and implementing any potential reintroduction efforts.

Cooperation and coordination with public land-management agencies will also be critical for reintroduction success. The U.S. Department of Agriculture’s Forest Service has the majority of modeled fisher habitat within their land-management authority (Table 2; Fig. 7), has expressed interest in actively participating in potential reintroductions of fishers, and has provided assistance and input with drafting this feasibility assessment. Other potential state and federal agencies that are expected to have interest in reintroduction efforts include the Department of Interior’s Bureau of Land Management, Oregon Department of Forestry, and Oregon Parks and Recreation Department. Tribal organizations in western Oregon are also likely to have interest in any future reintroduction efforts, and federal agencies will need to engage with the tribes under their tribal consultation requirements. Private landowners with substantial forest land ownership in western Oregon should also be invited to participate in the planning and implementation stages. Private forest landowners, as well other non-federal parties, can aid in the success of reintroductions and may be willing to provide conservation measures for fishers if they are given regulatory certainty should the fisher become listed under the federal ESA. More information on mechanisms to provide such certainty if fishers become listed is included in the Legal and Regulatory Requirements, Federal section of this assessment. As of early 2015, the U.S. Fish and Wildlife Service, Oregon Department of Wildlife, Oregon Department of Forestry, Oregon Forest Industries Council, and representatives from major forest landowners in Oregon are discussing potential conservation measures that would be necessary to address threats to fishers sufficient to either preclude listing or to provide regulatory certainty for affected landowners should the fisher become listed.

Any reintroduction efforts should be coordinated with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service-Wildlife Services due to their potential wildlife damage management activities in or near areas that might be utilized for reintroductions. The Oregon Trappers Association has expressed interest in fisher reintroduction efforts, and coordination with member activities (e.g., during harvest seasons) and sharing knowledge would also be beneficial for re-establishing fisher populations.

CONCLUSIONS AND RECOMMENDATIONS

The two extant fisher populations in southwestern Oregon seemingly have experienced little or no increase in distribution or abundance in recent years despite their long-term persistence. If long-term goals include increasing fisher population abundance and distribution in western Oregon, then there does not appear to be a suitable conservation alternative to reintroduction. By following protocols established in successful reintroductions previously described, fishers are a Feasibility assessment for reintroduction of fishers in western Oregon, USA 49

good candidate species for reintroduction into large landscapes of contiguous forested habitat (e.g., National Forests in Oregon). Several reintroductions in adjacent states (CA, WA) are currently underway and may be utilized as a template that can be adapted during planning stages should reintroduction efforts occur in western Oregon. This should help minimize the risk that reintroduction efforts in western Oregon would not meet project objectives.

Fishers naturally occur at low densities and no evidence suggests any substantial negative effects to species of concern in western Oregon or of undesirable ecosystem effects as a result of reintroducing fishers. Due to their generalist diet and opportunistic selection of prey species, fishers seem able to adapt to diverse prey conditions. Although population data are lacking for one (i.e., bobcats) of two primary predators associated with interspecific killing of fishers, relative densities of the other (i.e., mountain lions) are highest in areas with established fisher populations in Oregon. If founding individuals come from a source population with a similar carnivore community and landscape conditions (e.g., British Columbia), then reintroduced fishers would be expected to have a suitable level of adaptation for western Oregon.

Based on available evidence, the reintroduction of fishers in western Oregon is feasible. Based on coarse-scale habitat characteristics (U.S. Fish and Wildlife Service 2014c), high-quality habitat occurs within portions of central and northern coastal areas and within a larger extent of the west slope of the Cascade Range (Fig. 6). The west slope of the Cascades is the most suitable candidate area for reintroductions in western Oregon based on habitat quality (Fig. 6), contiguous forest conditions (Fig. 4), public landownership (Table 2, Fig. 7), lower risk of anticoagulant rodenticides (Fig. 11), specific forest and topographic characteristics (Figs. 4, 5, 9, and 10), and other factors (see Table 3). In addition to habitat conditions, there is potentially more land-use management control on the predominantly federal lands (i.e., Mount Hood, Umpqua, and Willamette National Forests) in this area. Although fragmented habitat should be avoided, at least during initial reintroduction efforts, if habitat is fragmented, reintroductions could be considered at multiple release sites in close proximity such that connectivity exists and metapopulations will have some level of emigration and immigration. If reintroduction efforts proceed within the west slope of the Cascades, information from that (and other efforts in California and Washington) may be applied to consider whether reintroductions should occur within coastal areas of Oregon.

Because the reintroduction of fishers in western Oregon is considered to be feasible, a reintroduction implementation plan would be a critical next step to clearly develop project objectives and provide detailed guidance on the process, to further examine proposed release areas, to develop a strategy to secure founders from a source population (ideally, British Columbia), and to develop a budget and strategy to secure the appropriate funding. Development of the implementation plan would require input and involvement from state and federal agency biologists, and would benefit by inclusion of tribal biologists, non-governmental conservation organizations, private timber industry companies, interested sporting groups, and other cooperators and stakeholders.

Using a home-range size of 64 km2 for female fishers reintroduced into the Olympic Fisher Recovery Area in Washington (Lewis 2014), and based on the areas containing high-quality habitat (Table 2), a coarse assessment suggests that the Willamette National Forest could support Feasibility assessment for reintroduction of fishers in western Oregon, USA 50

approximately 78 females with non-overlapping home ranges. Similarly, Mount Hood and Umpqua National Forests contain about 35 and 39 potential non-overlapping female home ranges, respectively. These coarse estimates do not incorporate habitat characteristics such as connectivity, and assume that all high-quality habitat would be occupied, but these three National Forests contain primarily contiguous high-quality habitat (Figs. 6 and 8). More specifically, at least 5 release areas, each encompassing approximately 1,280 km2 (494 mi2) to accommodate 20 non-overlapping home ranges for female fishers (Lewis 2014), could be considered for Mount Hood, Umpqua, and Willamette National Forests (Fig. 12). Each release site should be further examined and prioritized, including for potentially negative anthropogenic influences (e.g., sites B and E include paved roads), natural within-site barriers (e.g., sites A and C include bisecting major rivers), and other factors. This examination could occur in an implementation plan for reintroduction of fishers in western Oregon. Major roads and major rivers are unavoidable when considering potential barriers to large-scale habitat connectivity, but initial reintroduction decisions should attempt to minimize these factors during planning efforts.

An assessment of the potential negative effects of removing fishers from proposed source populations should be conducted to minimize any potential negative population effects in those areas. This also could be included in an implementation plan for reintroduction. Based on proximity to western Oregon, similarity of genetics, similarly of wildlife communities, and potential availability, fishers from British Columbia are the most appropriate founders for western Oregon. However, at some point in the future, potential also exists for southwestern Oregon (indigenous population), California, or Washington to serve as source populations if assessments of population status and effects of removals provide evidence that any are suitable candidates. Although the southern Oregon Cascades contain a reintroduced fisher population with non-native haplotypes, a situation that cannot be ignored, population recovery and connectivity of fishers in western Oregon will not be possible without its inclusion. This may be a departure from strict genetic baselines, but excluding this population in some manner may limit species-level recovery efforts for fishers and eliminate a potential benefit of increased genetic diversity (Jachowski et al. 2015). In addition, the current role of the existing reintroduced population in the ecosystem would not be expected to change and the genetic composition of fishers in the assessment area has changed substantially compared to the historical composition.

Feasibility assessment for reintroduction of fishers in western Oregon, USA 51

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Table 1. Vertebrate species of concern in western Oregon, USA; S = Oregon Conservation Strategy Species; P = Proposed, C = Candidate, T = Threatened, E = Endangered under Oregon Endangered Species Act or federal Endangered Species Act; I = listed in federal Interagency Special Status/Sensitive Species Program for western Oregon. Status Class Species Scientific name State Federal Known occurrence Aves Marbled murrelet Brachyramphus marmoratus S, T T, I Coast Northern spotted owl Strix occidentalis caurina S, T T, I Coast, Cascades Yellow-billed cuckoo Coccyzus americanus - T, I Coast, Cascades

Mammalia American (Pacific) marten Martes americana (caurina) S - Coast, Cascades Canada lynx Lynx canadensis - T, I Resident status unknown Columbian white-tailed deer Odocoileus virginianus leucurus - E, I Coast Fisher Pekania pennanti S PT, I Coast, Cascades Gray wolf Canis lupus E E, I Cascades Red tree vole Arborimus longicaudus S Ca, I Coast, Cascades Ringtail Bassariscus astutus S - Coast, Cascades Sierra Nevada red fox Vulpes vulpes necator - -b Cascades Wolverine Gulo gulo T I Cascades

Amphibia Oregon spotted frog Rana pretiosa S T, I Cascades a Candidate status is limited to the North Oregon Coast Distinct Population Segment. b Under federal review. Feasibility assessment for reintroduction of fishers in western Oregon, USA 73

Table 2. Estimated amount of high-quality habitat for fishers in western Oregon, USA, based on U.S. Fish and Wildlife Service (2014c). Ownership Agency Total area Amount (ha) Amount (%) Location (ha) of habitat of habitat Federal Bureau of Land Management Coos Bay 132,081 13,101 9.9 Eugene 127,210 64,682 50.8 Medford 351,266 160,081 45.6 Roseburg 172,391 73,677 42.7 Salem 162,535 113,680 69.9 National Park Service Crater Lake National Park 73,887 2,738 3.7 Forest Service Deschutes National Forest 679,179 32,851 5.1 Fremont-Winema National Forest 671,465 20,375 3.0 Mount Hood National Forest 415,164 224,525 54.1 Rogue River-Siskiyou National Forest 696,874 268,994 38.6 Siuslaw National Forest 252,917 30,727 12.1 Umpqua National Forest 398,866 254,109 63.7 Willamette National Forest 681,070 502,823 73.8 State Oregon Department of Forestry State Forests 300,346 109,134 36.3 Oregon Parks and Recreation Department State Parks 45,772 3,457 7.6 Tribal Coquille 2,549 0 0.0

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Table 3. Regional comparison for potential reintroduction of fishers in western Oregon, USA. Coast West Slope of Cascades Metric North Central North Central

Relative amount of high-quality habitat Medium Medium High High

Relative habitat connectivity Somewhat Somewhat Contiguous Contiguous patchy patchy

Public land ownership pattern Somewhat Somewhat Contiguous Contiguous patchy patchy

Fire danger class Low Low Low Low

Relative density of highways Medium Medium Low Low

Relative distance to current reintroduced fisher Distant Distant Medium Close population in Oregon

Relative distance to indigenous fisher population in Distant Distant Distant Medium Oregon

Relative level of snag density Low Low Low-medium Low-medium

Relative level of canopy cover Medium Medium High High

Relative level of down wood Medium Medium Medium Medium

Relative presence of rodenticidesa High Medium Medium Low a Based on known eradicated illegal marijuana cultivation sites. Feasibility assessment for reintroduction of fishers in western Oregon, USA 75

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A B

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A B