Pollinator Habitat Conservation Along Roadways, Volume 1: Alaska (2023)

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3-1 Chapter 3 Imperiled Pollinator Profiles No pollinators are covered by the federal Endangered Species Act (ESA) in Alaska, but there are pollinators in this region in need of conservation efforts. This section provides profiles of five species of imperiled pollinators found in Alaska (Table 3-1). These include pollinators that have the potential to be listed in the future, based on NatureServe rankings and expert opinion. The profiles of imperiled species cover three imperiled bumble bees and two imperiled butterflies. This is not an exhaustive list of all declining pollinators in the region; the focus is on species in need of conservation that have a broad distribution and those that are more likely to affect Departments of Transportation (DOTs). An overview of the basic biology of bees, butterflies, and other insect pollinators can be found in Chapter 2. This section presents information on life history, distribution, threats, and habitat requirements for imperiled pollinators in this region. Information on known adult flight times (i.e., the breeding period) and larval active times (for butterflies and moths; larval bees live within nests) are included. The profiles also include a list of important plants that are used by each species as host plants or for pollen and/or nectar. Some of these plants are nonnative species or noxious weeds. These species are included in the profiles, as the information may be useful, but using them in revegetation efforts is not recommended (see Chapter 7 for more). Some basic conservation recommendations and information on the effects of roadside management on each species are also provided, when such information is available. Insects generally tend to be less well studied than vertebrates; therefore, very little is known about the biology and habitat requirements of some of these species. Other pollinator species may be better studied, but rigorous studies of the effects of different management practices on the species or their habitat may still be lacking. The best possible recommendations are made based on the available information. The profiles provide information on life cycles, host plants, habitat needs, and adult flight times that can be used to tailor maintenance and revegetation decisions (Chapters 6 and 7). General active times for adults and larvae are also provided. It should be noted that active times may shift regionally, such as with elevation or latitude, or from year to year with changes in climate. However, consultation with local experts, as well as biologists from state and federal agencies, is recommended to help DOTs develop meaningful management plans for species of interest in their areas because the profiles cannot capture the site-specific nuances that should be considered. As the profiles indicate, habitat loss is a primary driver of species’ declines. Roads can be a source of habitat fragmentation (Box 5-3). However, with investments in high-quality revegetation (revegetation that prioritizes usage of native plants and high plant diversity, including an abundance of flowering plants that provide pollen and nectar or act as host plants for butterflies) where appropriate, roadsides can also provide an ideal opportunity to increase habitat connectivity for many species, including pollinators. It is important to note that although some of the species profiled in this section may be unlikely to use roadside habitat for breeding, individuals may still use roadside habitat for nectar or pollen or as movement corridors. Therefore, it is worthwhile to invest in high-quality habitat restoration projects along roadsides near natural areas, preserves, and populations of

Chapter 3. Imperiled Pollinator Profiles  3-2 imperiled species. Another common threat to many imperiled butterflies in the United States is noxious and invasive plants that displace required host plants. Here again, investing in high-quality habitat restoration using native plants can benefit imperiled pollinators, even if those pollinators are not using roadside habitat, by helping to slow the spread of invasive plants into key habitat areas. This section includes profiles of pollinator species that may not occur in roadside habitat but may be found in other DOT land holdings, such as mitigation areas (Table 3-1). Table 3-1. List of profiled imperiled pollinator species in the Alaska region. Scientific Name  Common Name  Status#  Declining Pollinator Species  Boloria frigga  Frigga fritillary  G5  Bombus bohemicus  Ashton’s cuckoo bumble bee  G3G5  Bombus occidentalis*  Western bumble bee  G3  Bombus suckleyi*  Suckley’s cuckoo bumble bee  G2G3  Oeneis alpina  Sentinel arctic butterfly  G4G5  * Species are under review or on the U.S. Fish and Wildlife Service workplan to be evaluated for listing  under the ESA as of March 2022.  # Status of pollinators is either the ESA status for listed species or is taken from NatureServe (accessed  March 2022) for species not listed under the ESA.    G1: Critically Imperiled. At very high risk of extinction due to extreme rarity (often five or fewer  populations), very steep declines, or other factors.   G2: Imperiled. At high risk of extinction due to very restricted range, very few populations (often 20 or  fewer), steep declines, or other factors.   G3: Vulnerable. At moderate risk of extinction due to a restricted range, relatively few populations  (often 80 or fewer), recent and widespread declines, or other factors.   G4: Apparently Secure. Uncommon but not rare; some cause for long‐term concern due to declines or  other factors.   G5: Secure. Common; widespread and abundant.   G#G#: Range Rank. A numeric range rank (e.g., G2G3) is used to indicate the range of uncertainty in  the status of a species or community.   T#: Infraspecific Taxon (for subspecies or varieties). The status of infraspecific taxa is indicated by a  “T‐rank” following the species’ global rank. For example, the global rank of a critically imperiled  subspecies of an otherwise widespread and common species would be G5T1.    

Chapter 3. Imperiled Pollinator Profiles  3-3 3.1 Frigga Fritillary (Boloria frigga)  Jan  Feb  Mar  April  May  June  July  Aug  Sept  Oct  Nov  Dec  Adult  Larvae  Adult Frigga fritillary (top left) and known state/province‐level distribution (top right). Adult flight times  (i.e., breeding period; blue) and larvae active periods (green) for this region are shown in the chart  (bottom). Lighter shades indicate uncertain but likely active times. See Life Cycle for more information.  Photo credit: Jukka Jantunen.    Order: Lepidoptera Family: Nymphalidae Status: Secure (G5) (Alaska) Distribution: Holarctic. In North America, this species is found from northern Alaska and Canada south through the Rocky Mountains to Colorado, and east to Labrador and northern Michigan. In the United States, it is documented from Alaska, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, Wisconsin, and Wyoming. Where it occurs: The frigga fritillary occurs in willow thickets and peat bogs in arctic/subalpine tundra areas. How to recognize: Adults are orange-brown with black markings on the upper side and 1.5- to 2-inch wingspans. Forewing tips are pointed. The underside of the hindwing is dark violet-gray on the outer part of the wing, with a noticeable white or off-white patch at the base of the leading edge. Caterpillars are black with black spines and purplish lateral lines. Life cycle: This species has a single brood, with adults active between June and July in western North America. The species overwinters as nearly full-grown larvae. Habitat needs: This species is a temperate-bog specialist, associated with willow and sphagnum bogs in arctic tundra regions). Known host plants include bog rosemary (Andromeda), cranberry (Vaccinium), birch (Betula), willow (Salix), and potentially entireleaf mountain-avens (Dryas integrifolia). This species may use a wide variety of larval host plants, and several of the observed host plants are a result of lab studies rather than observations in the field. Adults will also use a variety of plants, nectaring on willow, knotweed, bittercress, lousewort, stonecrop, and valerian, among others.

Chapter 3. Imperiled Pollinator Profiles  3-4 Top reasons for decline, if known: Reasons for decline of this species in certain parts of its range may be due to climate change, loss of habitat due to peat mining, and loss or degradation of larval host plant populations. General conservation recommendations: Perform management actions that protect or improve habitat for this species, including maintaining or restoring hydrologic regimes, protecting host plants, and controlling invasive vegetation. Protect bog habitats where this species is known or suspected to occur. Roadside management recommendations: Road construction and roadside management actions that lead to the removal or degradation of bog habitat in arctic tundra regions may have negative impacts on this species by reducing or removing larval host plants and adult nectar plants. Avoid spraying important nectar and host plants (Table 3-2) with herbicides. Table 3-2. Plants used by the frigga fritillary. Species Name  Common Name  Larval Host Plants    Salix spp.  Willow  Betula spp.  Birch  Dryas integrifolia  Entireleaf mountain‐avens1  Andromeda spp.  Bog rosemary  Vaccinium spp.  Blueberry2  Nectar Plants    Cardamine spp.  Bittercress  Pedicularis spp.  Lousewort  Polygonum spp.  Knotweed3  Salix spp.  Willow  Sedum spp.  Stonecrop  Valeriana spp.  Valerian3  1 Potential host  2 Specifically, wild cranberry  3 This genus includes native and nonnative species; some of the nonnative species can be invasive.  3.1.1 References Lotts, K., and T. Naberhaus, coordinators. 2017. Butterflies and Moths of North America. Available: www.butterfliesandmoths.org. Version 09292020.

Chapter 3. Imperiled Pollinator Profiles  3-5 NatureServe. 2020. NatureServe Explorer (web application). NatureServe, Arlington, VA. Available: https://explorer.natureserve.org/. Accessed: September 29, 2020. Scott, J. A. 1986. The Butterflies of North America: A Natural History and Field Guide. Stanford University Press, Stanford, CA. Scott, J. A. 2014. Lepidoptera of North America. 13. Flower visitation by Colorado butterflies (40,615 records) with a review of the literature on pollination of Colorado plants and butterfly attraction (Lepidoptera: Hesperioidea and Papilionoidea). Contributions of the C.P. Gillette Museum of Arthropod Diversity, Colorado State University. Scott, J. A. 2020. “Butterflies of the Southern Rocky Mountains Area, and Their Natural History and Behavior.” Papilio 27:1–391. Available: https://mountainscholar.org/ handle/10217/200723. Accessed: September 29, 2020. 3.2 Bumble Bees: Ashton’s Cuckoo Bumble Bee (Bombus  bohemicus), Western Bumble Bee (B. occidentalis),  Suckley’s Cuckoo Bumble Bee (B. suckleyi)  Order: Hymenoptera Family: Apidae Habitat Needs: Availability of food and nesting resources are key features in determining the success of a bumble bee colony. It is critical to maintain a bloom of floral resources throughout the spring, summer, and fall to supply bumble bees with a diversity and abundance of pollen and nectar, food for adults and larvae. Bumble bees nest above, on, or under the ground, utilizing pre-existing insulated cavities such as rock piles, areas of dense vegetation (e.g., bunch grasses), or old bird nests or mouse burrows. See Table 3-3 for a list of plants used by bumble bees. Top reasons for decline, if known: There are multiple factors affecting bumble bee decline including habitat loss, pesticide exposure, climate change, pathogens, and parasites, as well as the introduction of nonnative bee species. General conservation recommendations: Preserve, restore, and create high-quality habitat that includes suitable nesting, foraging, and overwintering sites throughout a species’ range. Assess and mitigate the risk of pesticide use in or near suitable habitat to avoid treating flowers in bloom or contaminating nesting and overwintering sites. Avoid the introduction of managed honey bees and managed bumble bees to areas of natural habitat to protect and minimize disease exposure. Roadside management recommendations: Intensive mowing may deplete floral resources and disturb species that have nested aboveground on the roadside. Reduced mowing frequency would alleviate this problem. In areas with aboveground nesting species, avoid mowing during the nesting season to avoid harming nests. Use a diversity of plants in revegetation to ensure that multiple species are in bloom from spring through fall. Blanket spraying of herbicides can affect the health of bumble bees in the area by reducing floral resources. A recent study of roadside mortality of bumble bee queens in Sweden found that bumble bee queens used roadsides with both high plant diversity and low plant diversity in similar

Chapter 3. Imperiled Pollinator Profiles  3-6 proportions when looking for nests. Queen mortality increased with traffic volume but was slightly lower along roadsides with higher quality vegetation. The authors recommend improving habitat quality along roadsides and keeping a mown buffer strip next to the road to reduce queen mortality. 3.2.1 Ashton Cuckoo Bumble Bee (Bombus bohemicus)   Jan  Feb  Mar  April  May  June  July  Aug  Sept  Oct  Nov  Dec  Adult                                                                                                Adult Ashton cuckoo bumble bee (top left) and known state/province‐level distribution (top right). Adult  flight times (i.e., breeding period) are shown in the chart (bottom). Photo credit: Gail Hampshire/Flickr  Creative Commons.    Status: Vulnerable to secure (G3G5) Distribution: Northeastern United States and Great Lakes region, Canadian Great Plains to tundra/taiga region of Alaska. Population has shown rapid decline throughout its range, most likely due to a decline in the host species. Where it occurs: Urban, shrubland, grassland Parasite of: In Alaska, very likely a parasite of western bumble bee (B. occidentalis) and cryptic bumble bee (B. cryptarum). Flight Time: This species is typically active on the landscape between late May and early September (Williams et al. 2014). Nesting behavior: Parasite of B. occidentalis and B. cryptarum, which nest underground. How to recognize: This bumble bee has mixed black hair on the face. The thorax has a yellow band in front of the wings, with a black band or spot between wings; the area behind the wings can be black, yellow, or mixed. The abdomen’s anterior is half black and the posterior half has yellow lateral patches, with white hairs medially. The last segment is black. Males may have different color patterns. Body size: Medium. Females range from 17 to 19 millimeters (0.65 to 0.73 inch).

Chapter 3. Imperiled Pollinator Profiles  3-7 3.2.2 Western Bumble Bee (Bombus occidentalis) Jan  Feb  Mar  April  May  June  July  Aug  Sept  Oct  Nov  Dec  Adult  Adult western bumble bee (top left) and known state/province‐level distribution (top right). Adult flight  times (i.e., breeding period) are shown in the chart (bottom). Photo credit: Rich Hatfield.    Status: Vulnerable (G3); under review; petitioned in 2015 to be listed as endangered or threatened under the ESA Distribution: Western United States from the coast to mountain meadows out to the northwestern Great Plains. Population has shown sharp decline since the late 1990s west of the Sierra-Cascade ranges. Where it occurs: Urban, shrubland, grassland Flight Time: This species is typically active on the landscape from May through September. Between October and April, queens are overwintering in the ground. Nesting behavior: Usually nests underground. How to recognize: This bumble bee has mixed black and yellow hair on the face. The thorax has a yellow band in front of the wings and a black band or spot between the wings; behind the wings can be black, yellow, or mixed. Segment one of the abdomen is black, segments two and three are black or have some yellow, segments four and five are white or pale yellow, and segment six is black. Males may have different color patterns. Body size: Medium. Queens range from 20 to 21 millimeters (0.77 to 0.84 inch) and workers range from 9 to 15 millimeters (0.36 to 0.59 inch).

Chapter 3. Imperiled Pollinator Profiles  3-8 3.2.3 Suckley’s Cuckoo Bumble Bee (Bombus suckleyi)   Jan  Feb  Mar  April  May  June  July  Aug  Sept  Oct  Nov  Dec  Adult                                                                                                Adult Suckley’s cuckoo bumble bee (top left) and known state/province‐level distribution (top right). Adult  flight times (i.e., breeding period) are shown in the chart (bottom). Photo credit: Cory Sheffield.      Status: Imperiled to vulnerable (G2), S1 (Alaska) Distribution: Mountain west and north into Canada Where it occurs: Forest, grassland, shrubland Parasite of: Western bumble bee (B. occidentalis) Flight Times: This species is typically active on the landscape in June and again in early to mid-August. During the peak of summer, this species remains in the nest. Nesting behavior: Parasite of western bumble bee, which nests underground. How to recognize: This bumble bee has black hair on the face and a predominantly yellow thorax with a black stripe between the wings. The abdomen is predominantly black with a yellow band toward the posterior end interrupted medially. Males may have different color patterns. Body size: Medium. Females range from 18 to 23 millimeters (0.72 to 0.92 inch).

Chapter 3. Imperiled Pollinator Profiles  3-9 Table 3-3. Plants used by bumble bees. Species Name by Bloom  Period  Common Name  Notes  Early  Armeria maritima  Thrift seapink  Pink; perennial  Hedysarum boreale  Utah sweetvetch  Pink; perennial  Lupinus nootkatensis  Nootka lupine  Purple; perennial  Prunella vulgaris ssp.  lanceolata  Lance selfheal  Purple; perennial  Mid  Astragalus americanus  American milkvetch  White; perennial  Dasiphora fruticosa ssp.  floribunda  Shrubby Cinquefoil  Yellow; perennial  Hedysarum alpinum  Alpine sweetvetch  Pink/purple; perennial  Rosa nutkana  Nootka’s rose  Pink; perennial  Late  Chamerion angustifolium  Fireweed  Pink; perennial  Potentilla arguta  Tall cinquefoil  White/yellow; perennial  Solidago canadensis  Canada goldenrod  Yellow; perennial  Symphyotrichum subspicatum  Douglas aster  Purple; perennial  3.2.4 References Dániel-Ferreira, J., Å. Berggren, R. Bommarco, J. Wissman, and E. Öckinger. 2022. Bumblebee queen mortality along roads increase with traffic. Biological conservation 272:109643. Hatfield, R., S. Jepsen, E., Mader, S. H. Black, and M. Shepherd. 2012. Conserving Bumble Bees. Guidelines for Creating and Managing Habitat for America's Declining Pollinators. The Xerces Society for Invertebrate Conservation, Portland, OR. Williams, P. H., R. W. Thorp, L. L. Richardson, and S. R. Colla. 2014. Bumble Bees of North America: An Identification Guide. Princeton University Press, Princeton, NJ. doi:10.2307/j.ctt6wpzr9.

Chapter 3. Imperiled Pollinator Profiles  3-10 3.3 Sentinel Arctic Butterfly (Oeneis alpina)  Jan  Feb  Mar  April  May  June  July  Aug  Sept  Oct  Nov  Dec  Adult  Larvae  Adult sentinel arctic butterfly (top left) and known state/province‐level distribution in North America (top  right). Adult flight times (i.e., breeding period; blue) and larvae active periods (green) are shown in the  chart (bottom). Lighter shades indicate uncertain but likely active times. See Life Cycle for more  information. Photo credit: Pavel Gorbunov.  Order: Lepidoptera Family: Nymphalidae Status: Apparently secure to secure (G4G5), S3 (Alaska) Distribution: Alaska, Canada Where it occurs: Rocky scree areas in tundra habitat How to recognize: This species has a wingspan of 1.5 to 1.75 inches. The forewings are shorter than the hindwings. Upper sides of the wings are orangish-brown, with two diffuse eyespots. Undersides of the hindwings have mottled black-brown stripes, with some yellow and white coloring. Undersides of the forewing are orangish-brown, with oval, whitish eyespots surrounded by a diffuse dark border. Life cycle: Adult flight occurs from June to mid-July. Much is still unknown about this species’ life history. They most likely use grasses, including Poa spp., as host plants. Larvae may overwinter twice before pupating in spring or summer. Nectar plants used by adults are unknown. Habitat needs: Inhabits wet, grassy tundra. Males often use nearby ridges and rocky areas, including gravel patches along roads. Gravel areas near Oil Spill Hill on the Dalton Highway are favored locations. Top reasons for decline, if known: Unknown, but habitat loss and climate change may present future threats to this species. General conservation recommendations: Research is needed on this species’ life history and responses to management and restoration practices. In general, protecting habitat, increasing habitat connectivity, controlling invasive plants, and reducing pesticide exposure should all be beneficial. More specific recommendations require a better understanding of this species’ population status and biology.

Chapter 3. Imperiled Pollinator Profiles  3-11 Roadside management recommendations: Unclear, but actions that destroy, fragment, or degrade habitat are likely to have negative impacts on this species. Because this species has been found along roadsides, avoiding herbicide applications to native plants will benefit patrolling adult males. 3.3.1 References NatureServe. 2020. NatureServe Explorer (web application). NatureServe, Arlington, VA. Available: https://explorer.natureserve.org/. Accessed: October 29, 2020. Opler P. A. 1999. Peterson Field Guide to Western Butterflies. Houghton Mifflin Company, New York, NY. Philip, K. W., and C. D. Ferris. 2016. Butterflies of Alaska, A Field Guide. Second edition. Alaska Entomological Society, Fairbanks, AK. Scott, J. A. 1986. The Butterflies of North America: A Natural History and Field Guide. Stanford University Press, Stanford, CA.