Northwest Science 97(2)

A survey of the diversity of butterflies in King County, Washington, USA - Benjamin Mous

A five year field survey of the butterflies (Rhopalocera) of King County, Washington was conducted from August 2017 to August 2022 to compare the current butterfly fauna with historical records from the previous 140 years, and to expand our knowledge of butterfly diversity and distribution in this highly urbanized county. King County (5478 km²) is the most populous county in the state and has a wide variety of ecosystems, including three Level III ecoregions. For this survey, 73 sites were sampled for butterfly species occurrence, from sea level to 1700m (5600ft) elevation and with multiple sites in each ecoregion. The species recorded during this survey are compared to those recorded historically (pre-1996) from King County in Hinchliff (1996), as well as with the sum of currently known King County records. Notable changes in species diversity and the impacts of urbanization are discussed. All records and literature pertaining to the species not recorded during this survey but known to have occurred in King County are reviewed. A total of 63 species were recorded, including six species and one subspecies which were first records for King County. A total of 87.7% of the species recorded in Hinchliff (1996) and 85.1% of all recorded King County species were found during this survey. The history of the literature relating to the study of butterflies of King County is also discussed, as well as the notable species found during this survey.

The complete pre-print version of this article is available here. The butterfly species below (Figure 2) were new records for King County, Washington.

Documenting historical anchorworm parasitism of introduced warmwater fishes in the Willamette River Basin, Oregon - Elena Eberhardt, Christina Murphy, William Gerth, Peter Konstantinidis, Ivan Arismendi

Anchorworms (Lernaea spp.) are freshwater parasitic copepods that use a wide range of hosts. Yet, little is known about their prevalence, distribution, and which species are their primary fish hosts in the state of Oregon. Institutional fish collections serve as banks which allow investigators to look at historical fish specimens and ascertain their health status at the time of their collection. We examined 1,039 specimens collected between 1941 and 2016 from the Oregon State Ichthyology Collection to detect the presence of anchorworms on non-native warmwater fishes from the Willamette River Basin, Oregon. Adult female anchorworms were found on eleven of the seventeen fish species that we examined. The most infected species included Common Carp (Cyprinus carpio), Bluegill (Lepomis macrochirus), and Smallmouth Bass (Micropterus dolomieu). We suggest these introduced warmwater fishes can act not only as hosts, but also as potential reservoirs for these understudied parasites posing a potential risk for Endangered Species Act (ESA)-listed native fishes. Our findings reveal unique insights that will serve as a baseline to detect future changes in parasite loads in the Willamette River Basin.

The complete pre-print version of this article is available here.

Earthquake effects surveyed during the nineteenth century as ecological features of Chinookan tidelands - Brian F. Atwater, David K. Yamaguchi, Jessie K. Pearl

Lasting effects of a Cascadia earthquake in 1700 were documented during surveys of Chinookan tidelands near the mouth of the Columbia River between 1805 and 1868. The effects resemble estuarine consequences, near Anchorage, of the 1964 Alaska earthquake: fatal drowning of subsided meadows and forests by post-earthquake tides, rebirth of marshes and forests through post-earthquake sedimentation and uplift. Chinookan remains of killed forests were recorded by James Graham Cooper, John J. Lowell, and Cleveland Rockwell. Cooper, attached to a railroad survey and the Smithsonian Institution, wrote of redcedar stumps and trunks standing dead in tidal marshes of Shoalwater (now Willapa) Bay. Two such snags served as bearing trees for Lowell as he platted a Shoalwater Bay township under contract with the General Land Office. Rockwell, of the U. S. Coast Survey, flecked landward edges of tidal flats west of Astoria with symbols that evoke remains of a bygone spruce forest. The Lewis and Clark Expedition, while in that area in 1805–1806, mapped and puzzled over tideland vegetation that post-1700 succession helps explain.

The complete pre-print version of this article is available here. Below, from the township survey, redcedar trunks interpreted today as victims of a 1700 Cascadia earthquake (Figure 5d).

River channel response to the removal of the Pilchuck River Diversion Dam, Washington State - Scott W. Anderson, Brett Shattuck, Neil Shea, Catherine M. Seguin, Joe J. Miles, Derek Marks, Natasha Coumou

In August 2020, the 3-m tall Pilchuck River Diversion Dam was removed from the Pilchuck River, allowing free fish passage to the upper third of the watershed for the first time in over a century. The narrow, 300-m long impoundment behind the dam was estimated to hold 4,000-7,500 m³ of sand and gravel, representing less than one year’s typical bedload flux. Repeat cross section surveys, stage sensors, and time lapse cameras were used to document the physical channel response over the first year following dam removal. A total of 7,400 m³ (~100 %) of impoundment sediment was eroded in the first year, with 25 percent accomplished by manual regrading during dam removal. Most river-caused erosion occurred during a sequence of modest flows in October 2020. Downstream deposition totaled 4,300 m³, predominately filling in the first 100 m downstream of the dam site. Deposition tapered below detectable levels within 350 m, and most downstream channel adjustments occurred before November 2020. Multiple high flows after December 2020 caused little upstream or downstream change. The physical river response to this dam removal then appears to have been largely accomplished within several months by modest flows, consistent with pre-removal modeling and observations from other regional dam removals. Efficient sediment evacuation was likely aided by the narrow and steepwalled impoundment geometry. Our observations support existing guidance that the physical river response to small dam removals is typically rapid and modest; the benefits of removal may then often be gained with minimal negative downstream geomorphic impacts.

The complete pre-print version of this research note is available here. A 2020 image of the Pilchuck River Diversion Dam, 3-m tall and 18-m wide is displayed below (left), alongside graphical representation of channel volumetric change (July 6, 2020, to July 19, 2021) following dam removal.

Northwest Science 97(1)

Potential Nutritional Effects of Missed Feedings to Marbled Murrelet (Brachyramphus marmoratus) Chicks due to Disturbance - Suzanne L. Nelson, Katherine Fitzgerald

The marbled murrelet is a federally threatened seabird that continues to decline throughout its range. Murrelets utilize late-successional and old growth coastal forest as nesting habitat, and forage in the marine environment. Murrelet adults invest heavily in raising a single young per year, and chicks are dependent on adults for all their nutrition during the 27- to 45-day nestling period. Rates of nestling growth and development are highly sensitive to food quality and quantity. We developed a nutritional model that examines the effects of disturbance that result in missed feedings for murrelet chicks. Six dietary scenarios were developed to simulate murrelet chick feeding; a high quality, intermediate, and low quality diet, and one or two feedings were missing from each diet. Five of the six scenarios resulted in insufficient calories for marbled murrelet chicks, with only the high quality diet able to provide sufficient calories with one missed feeding. The intermediate and low quality diets with missed feedings were not able to meet the metabolic requirements of the developing chick, and over time would result in growth stunting and starvation. Future conservation actions should focus on avoiding disruptive activities at places and times when adult murrelets are likely to be engaged in meal deliveries to chicks, and on improving forage conditions for murrelets.

The complete pre-print version of this article is available here.

Patterns of Prairie Soil Preference and Occupancy for the Threatened Mazama Pocket Gopher in Washington – Suzanne L. Nelson, Michael C.T. Carlson

Mazama pocket gophers (Thomomys mazama) act as ecosystem engineers and are keystone species on the remnant glacial prairies of the southern Puget Sound lowlands. Three subspecies of Mazama pocket gophers are regionally endemic to Thurston County, Washington, and were federally listed as threatened in 2014. We examined patterns of occupancy and habitat and differences between subspecies for soil type preference. In total, 1,241 Mazama pocket gopher surveys, comprising approximately 4,654 hectares, resulted in 165 occupancy sites. Pocket gophers were detected more often on sites with more preferred soils than on less preferred soils (p < 0.01), though there were differences in occupancy rates between subspecies. Soil type and availability can act as surrogates of gopher habitat availability. Such quantification of habitat availability and potential loss is important given the absence of population estimates. Therefore, the conservation of undeveloped lands with soils identified a priori as preferred is necessary for both the recovery and continued persistence of Mazama pocket gophers.

The complete pre-print version of this article is available here. Below (Figure 1), the Yelm pocket gopher (Thomomys mazama yelmensis) is one of three subspecies of Mazama pocket gopher that is regionally endemic to Thurston County.

Scanning the horizon for potential nonnative aquatic plant and algae arrivals to the Pacific Northwest – SOTS 2022 – Katherine E. Wyman-Grothem, Theresa A. Thom, Heidi L. Himes

To date, the Pacific Northwestern United States has experienced fewer nonnative species introductions than other parts of the country, presenting an opportunity to minimize future harm from invasive species by investing in prevention efforts. Horizon scanning for potential future invasive species provides foundational data for developing efficient prevention and early detection strategies. We gathered more than twenty Federal, State, Tribal, local government, University, and industry partners to provide input on priority geography, introduction pathways, and taxa for a horizon scan focused on the Pacific Northwestern United States. The scope of this initial effort included submerged or floating aquatic plants and algae that could be introduced to the region via movement of recreational boats. Watercraft inspection data were combined with climate matching analyses to identify “top donor regions” from which submerged or floating aquatic plants were most likely to arrive. We identified five aquatic plants as posing high risk to the Pacific Northwest on the basis of climate match and prior history of invasiveness in other locations: Carolina mosquitofern (Azolla caroliniana), crested mosquitofern (Azolla cristata), Indian swampweed (Hygrophila polysperma), wingleaf primrose-willow (Ludwigia decurrens), and water spangles (Salvinia minima). Another 21 species pose uncertain risk given available information. These results can be used to inform regulatory actions, improve training, and refine detection tools and strategies on a local, regional, and national level. More broadly, this horizon scan provides a template for future horizon scanning for other geographies, pathways, and taxonomic groups.

The complete pre-print version of this article is available here.

Comparison of Gravimetric and Volumetric Methods to Estimate Brook Trout (Salvelinus fontinalis) Fecundity – Science of the Service 2022 – Nolan P. Banish

Estimating fish fecundity is important for developing accurate population models and informed management decisions. Fecundity can be determined by tedious, complete oocyte counts. Researchers save time by counting a subsample of oocytes, measuring the subsample and total ova volume and weight, and extrapolating to produce fecundity estimates using volumetric and gravimetric methods. Volumetrically and gravimetrically generated fecundity estimates from 70 brook trout (Salvelinus fontinalis [range 143–356 mm]) captured from Long Creek, Oregon, were compared to total oocyte counts to evaluate the accuracy and precision of each method. The average total oocyte count was 775 (SD + 354.8). The mean difference between total oocyte count and extrapolated count based on the gravimetric method was 111.2 (SD + 154.0) and 165.9 (SD + 279.0) for the volumetric method. Gravimetric and volumetric fecundity estimates were closely correlated with total oocyte counts, although both were positively biased. Volumetric estimates were on average 1.100 times true fecundity (95% CI = 1.05, 1.15) and gravimetric estimates were 1.086 times true fecundity (95% CI = 1.05, 1.12). The gravimetric estimation method was less biased than the volumetric method and this bias should be weighed in management decisions that require accurate fecundity estimates.

Human and wildlife use of mountain glacier habitat in western North America – Scott Hotaling, Jordan Boersma, Neil A. Paprocki, Alissa Anderson, Logan Whiles, Lucy Ogburn, Sophia Kasper, Catharine White, Daniel H. Thornton, Peter Wimberger

The global recession of glaciers and perennial snowfields is reshaping mountain ecosystems. Beyond physical changes to the landscape and altered downstream hydrology, the implications of glacier decline for biodiversity are poorly known. Before predictions can be made about how climate change will affect wildlife in glacier-associated ecosystems, a more thorough accounting of the role that glaciers play in species’ life histories is needed. In this study, we deployed an elevational transect of wildlife cameras along the western margin of the Paradise Glacier, a rapidly receding mountain glacier on the south side of Mount Rainier, WA, USA. From June to September 2021, we detected at least 16 vertebrate species (seven birds, nine mammals) using glacier-associated habitats over 770 trap nights. Humans, primarily skiers, were the most common species detected, but we also recorded 99 observations of wildlife (birds and mammals). These included three species of conservation concern in Washington: wolverine (Gulo gulo), Cascade red fox (Vulpes vulpes cascadensis), and white-tailed ptarmigan (Lagopus leucura). Collectively, our results reveal a rich diversity of wildlife using a single mountain glacier and adjacent habitat in the Pacific Northwest, emphasizing a largely overlooked risk of climate change to mountain biodiversity. We conclude by highlighting the global need for similar studies to better understand the true scale of biodiversity that will be impacted by glacier recession in mountain ecosystems.

The complete pre-print version of this article is available here. Camera trap images below (Figure 3) document the presence of three wildlife species of conservation concern in Washington.

Bull Trout Passage at Beaver Dams in Two Montana Streams – J. Marshall Wolf, Niall G. Clancy, Leo R. Rosenthal

Beaver (Castor canadensis) translocation and mimicry is an increasingly popular set of tools for process-based restoration of degraded streams. Previous studies indicate that spring-spawning salmonid fishes can pass beaver dams in higher proportions than fall-spawning species. Thus, restoration or mimicry of beavers in streams containing threatened, fall-spawning bull trout (Salvelinus confluentus) is of concern to many biologists. We evaluated bull trout passage at beaver dams in two Montana streams: Meadow Creek (East Fork Bitterroot River drainage) in summer 2020 and Morrison Creek (Middle Fork Flathead River drainage) from 1997 to 2011. In Meadow Creek, 16% of PIT-tagged bull trout which entered a large beaver dam complex were detected upstream of some dams, but no fish moved through the entire 1 km complex. The redds in Morrison Creek occurred below beaver dams in higher proportion than if random spawning-site selection had occurred. Redds were found above some beaver dams during all 9 years they were present. These results suggest that beaver dams can affect the movement of bull trout and that passage depends on the characteristics of individual dams and reach geomorphology. Our methods cannot distinguish between inhibition of fish movement and selection of beaver-created habitats by fish due to the limited data we had on spawning habitat. Therefore, we suggest future research on beaver restoration in streams with bull trout be carefully monitored and conducted in an adaptive framework. Comparing spawning-site selection and fish movement in streams with and without beaver may provide additional information.

The complete pre-print version of this article is available here. Below, the location of Meadow Creek and Morrison Creek (Figure 1), two streams in northwestern Montana, in which bull trout (Salvelinus confluentus) passage was studied.

Geoarchaeological Record of the AD 1700 Earthquake and Tsunami at the Salmon River Wet Site, Central Oregon Coast – Rick Minor, Alan R. Nelson

Coseismic subsidence is a major contributor to the scarcity of evidence in the archaeological record of prehistoric earthquakes along coasts of the Cascadia subduction zone. The stratigraphy of suddenly subsided tidal wetlands, in places overlain by tsunami-deposited sand, records a long history of great (magnitude 8–9) earthquakes over the last 3000–7000 years. The most recent of these great earthquakes and its accompanying high tsunami occurred on January 26, 1700. Here we synthesize geologic and archaeological investigations in the Salmon River estuary on the central Oregon coast. Following coastal subsidence of 1.4 ± 0.4 m during the AD 1700 earthquake, the site of a prehistoric settlement was submerged and covered by tsunami sand and tidal mud, creating an archaeological “wet site” subject to erosion in the tidal zone. Excavations in the last remnants of the eroding cultural deposits recovered evidence of a Tillamook Indian hunting camp occupied within a few hundred years before the AD 1700 earthquake. The Salmon River Wet Site, and similar submerged archaeological deposits in other estuaries, constitute rapidly disappearing evidence of coseismic subsidence during the AD 1700 earthquake along the Cascadia subduction zone on the north Pacific coast.

The complete pre-print version of this article is available here. Below, cultural remains are excavated from sediment in a riverbank (Figure 4b).

Reconsidering Subspecific Taxonomy of Odocoileus virginianus in Oregon and Washington – Winston. P. Smith, Leslie N. Carraway, Thomas A. Gavin, Jonathan A. Jenks

Two subspecies of Odocoileus virginianus are recognized in the northwestern United States: O. v. leucurus (Douglas, 1829) and O. v. ochrourus Bailey, 1932. Historically, O. v. leucurus was common along the lower Columbia River and the name was applied to all populations in western Oregon as far south as Grants Pass. Today, O. v. leucurus is limited to populations along the Lower Columbia River and another in Douglas County, Oregon. Examination of 35 electrophoretic loci in 1988 did not support current subspecific taxonomy of O. virginianus in Oregon. Analysis of 18 cranial dimensions among three disjunct populations of O. virginianus in 2003 revealed variation that sorted into three distinct morphological groups in Oregon. Analyses of mtDNA and microsatellites at 15 autosomal loci from three subspecies of O. virginianus and two subspecies of Odocoileus hemionus (Rafinesque, 1817) revealed that each O. v. leucurus population possessed unique haplotypes, whereas O. v. ochrourus shared haplotypes with populations to the east. The most genetically differentiated whitetails were the two populations of O. v. leucurus (FST = 0.31), which were similarly differentiated from O. v. ochrourus (FST = 0.17-0.19); FST between O. h. hemionus and O. h. columbianus (Richarson, 1829) was 0.10. Thus, O. v. leucurus populations appear morphologically and genetically more different from each other than either is from O. v. ochrourus. Moreover, genetic differentiation among the three O. virginianus populations exceeds differentiation for existing subspecies of O. hemionus. We conclude the evidence warrants describing a new subspecies of O. virginianus in southwestern Oregon.

The complete pre-print version of this article is available here. Images below (Figure 5), display the skull, with antlers, of the Holotype of Odocoileus virginianus douglasi, white-tailed deer.

Northwest Science 96

Non-breeding-season Site Fidelity and Evidence of Migration of Steller Sea Lions (Eumetopias jubatus) - Grey W. Pendleton, Lauri A. Jemison

Most research that has been done regarding Steller sea lions (SSLs; Eumetopias jubatus) has been during the breeding season. Adult SSLs are known to have high among-year breeding-season site fidelity, typically with movement away from breeding-season locations during non-breeding seasons. Using non-breeding-season sighting data of permanently-marked SSLs from four areas in Alaska and more broad-scale breeding-season sightings, we estimate among-year non-breeding-season site fidelity (i.e., the probability a SSL moves from its breeding season location to a specific non-breeding-season area). Some SSLs, especially females, have high site fidelity to non-breeding-season areas; fidelity is markedly lower for males. We found no evidence that site fidelity varied among natal rookeries, but our sample sizes are relatively small, possibly limiting our ability to determine such effects. With our estimates of non-breeding-season site fidelity, coupled with previously demonstrated breeding-season site fidelity, we conclude that SSLs should be considered to be partial migrants (i.e., migratory behavior exhibited by only some individuals in a population) with at least some individual SSL, particularly females, exhibiting migratory behavior.

Long-term Monitoring of Rocky Intertidal Communities: Lessons and Implications from the Redwood National and State Parks, Northern California - David Lohse, Karah N. Ammann, Eric C. Dinger

A challenge modern-day ecologists and resource managers face is how to separate natural variations in populations from changes caused by human activities (e.g., climate change). Long-term monitoring programs provide valuable information to assist in this endeavor. This study details the initial findings of a long-term monitoring program initiated in 2004 to monitor changes in rocky intertidal communities within Redwood National and State Parks (RNSP), located in northern California. Permanent plots were established at three sites using protocols developed by MARINe (Multi-Agency Rocky Intertidal Network), a consortium that monitors rocky intertidal communities along the western coast of North America. Replicate plots were set-up to monitor changes in abundance of key intertidal taxa, including mussels (Mytilus californianus), barnacles (Chthamalus dalli and Balanus glandula), red alga (Endocladia muricata), and rockweeds (Pelvetiopsis limitata and Fucus gardneri). Plots have been sampled annually since they were established. Results from the first 15 years of this study indicate that all taxa exhibited substantial short-term (annual) variation, with barnacles and Endocladia exhibiting the most. For barnacles, such variations were correlated with measures of recruitment. Except for Pelvetiopsis, all other target taxa experienced at least one period of large-scale major change, where abundances decreased dramatically (> 50%) simultaneously in most plots. However, in almost all cases abundances recovered, resulting in no apparent long-term changes. For the few instances where long-term changes were detected, it is possible this result may be an artefact of the analytical methods used to assess them. The potential implications of this finding are discussed.

Evidence of Bumble Bee Extirpation and Colonization, Galiano Island, British Columbia, Canada - Andrew D. F. Simon, Lincoln R. Best, Brian M. Starzomski

We present evidence for historical change in a bumble bee community on Galiano Island, British Columbia, Canada, including the probable extirpation of three bumble bee species—Bombus insularis (Smith, 1861), B. occidentalis Greene, 1858 and B. suckleyi Greene, 1860—as well as the disappearance of two species represented by singletons in the historical record: B. fervidus (Fabricius, 1798) and B. flavidus Eversmann, 1852. Evidence is based on a comparison of historical and contemporary species occurrence data, including recent data from intensive sampling targeting bumble bees using blue vane traps. The decline of B. occidentalis in southern portions of its range has long been observed, yet to our knowledge this is the first established case of its probable extirpation within an extensively surveyed part of its range. Results indicate that an additional species, B. vosnesenskii Radoszkowski, 1862, which has been expanding its range in the wake of the decline of B. occidentalis, may be a recent arrival on Galiano Island. Elsewhere in the region, B. vosnesenskii has become a dominant species, particularly in urban environments. However, our data show it to be the least abundant species on this largely forested island. We also report patterns in the occurrence of B. sitkensis Nylander, 1848 and B. vosnesenskii suggesting that niche segregation may confound the effect of competitive exclusion previously reported for these species. Potential factors contributing to this likely case of bumble bee extirpation and subsequent colonization are discussed in the context of Galiano Island’s historical land use and ecology. In conclusion, we assess the potential for community science to aid in the detection of ecological change via comparison of historical baseline and contemporary crowd-sourced biodiversity data.

A Decade of Understory Community Dynamics and Stability in a Mature Second-growth Forest in Western Washington – Ida Rex, Dylan G. Fischer, Ryan Bartlett

It is often assumed that dominant forest understory communities are predictably associated with overstory tree species, yet several long-term studies suggest that understory communities are more independent of overstory change. We use a 10–year dataset to explore variation in understory communities in a mature second-growth temperate forest in Western Washington. We classify all recorded species into six growth-forms (graminoids, ferns, shrubs, subshrubs, saplings, herbaceous species), and introduced species, (collectively grouped) to analyze responses to overstory productivity, stand age, canopy heterogeneity, soil type, stand type, and proximity to a canopy-gap forming pathogen (Phellinus weirii), as well as overstory C changes though the decade. Plant diversity and cover declined marginally through time (Shannon’s H’ declined by 8%; and cover by 4.5%) as plots remained dominated by clonal species Polystichum munitum and Gaultheria shallon. Species richness decreased significantly by 23% between years (mean plot richness 10.02 in 2008 to 8.05 in 2018), and diversity, sub-shrubs, and shrubs generally declined with stand age. Shrubs were more abundant in conifer dominated plots. Ferns, and changes in ferns, were associated with presence of P. weirii, where cover increased in infected plots. Ordination results suggested community composition was correlated with changes in canopy cover (conifer forests) and stand age (deciduous forests). Changes in total plot C and canopy cover were also associated with diversity and total cover. Nevertheless, our results support incremental changes in understory communities on decadal time scales and limited predictability of the understory based on the overstory.

Bee Community Differences Among Urban and Rural Sites in Oregon’s Willamette Valley – Briana C. Lindh, Annie Jolliff, Samantha Coleman, Marceline Skelton, Olivia Mack, Molly Hansen

We explored differences in bee communities between urban sites in the city of Salem and nearby rural sites with restored areas. While cities provide habitat for some wild pollinators, urban bee communities tend to exhibit different composition than rural ones, with urban communities particularly lacking ground-nesting and specialist oligolectic bees. We wanted to know whether these differences would still be present in a small city that is set in a heavily degraded rural landscape. We expected that bees with narrow diet breadth would primarily use native floral resources. We found that urban and rural sites exhibited distinctly different bee community composition, both in 2018 and 2019. The rural indicators matched our predictions, but there were some surprising large-bodied ground nesters present in the city. The Bombus and Lasioglossum species that were the major drivers of the urban-rural differences were primarily associated with exotic plants in rural areas. Extreme specialist bees that used only one native plant genus were present only in rural restoration sites, but their numbers were too small to generate statistically significant patterns. Our results suggest that rural and urban land managers should be aware of the importance of the mass of floral resources provided by exotics and of the crucial importance of certain native plants that host specialist bees.

Classification and Assessment of Riparian Ecosystems in Northwest Oregon for Restoration Planning – Steven A. Acker, Gordon H. Reeves, Johan B. Hogervorst, Brett Blundon, Ian-Huei Yau, David M. Bell

Riparian ecosystems are a critical ecological component in the Pacific Northwest. Many have been altered by human activities and need restoration. Establishing restoration objectives is daunting because of inherent spatial and temporal variation of geomorphology, disturbance regimes, and vegetation. We developed an analytical framework using geology and climate as the template for natural disturbance processes influencing riparian vegetation in northwest Oregon. We identified three ecoregions with contrasting geology and climate: Coast Range, dissected topography and rain-dominated hydrology; Western Cascades, dissected topography and rain- and snow-dominated hydrology; and High Cascades, undulating topography and snow-dominated hydrology. For all three, the most abundant stream reach type was small (< 15 m channel width) with wildfire the predominant natural disturbance. However, reaches affected by geomorphic disturbance were common for the Coast Range and West Cascades. Riparian vegetation dominated by large trees (≥ 51 cm diameter) is underrepresented compared to reference conditions for the Coast Range and West Cascades. Variation between subbasins in departure of current from reference conditions is greatest in the West Cascades and negligible in the High Cascades. Vegetation in the Coast Range has moved in recent decades towards reference conditions. Wildfires since the latest remote-sensing-derived data (2017) may have altered riparian vegetation, affecting departure of current from reference conditions. Since the remote sensing of vegetation continues, it should be possible to assess these effects. Our results support restoration of riparian forests dominated by large trees in the Coast Range and West Cascades. Areas dominated by smaller trees may represent restoration opportunities.

Ecological Characteristics of Diurnal Rest Sites Used by Ringtails (Bassariscus astutus) – Kathleen P. Gundermann, David S. Green, Frances E. Buderman, Cale H. Myers, J. Mark Higley, Richard N. Brown, Sean M. Matthews

The ringtail (Bassariscus astutus) is a species of conservation concern. Yet, little is known about their basic ecology in the northwestern edge of their range, where the habitat differs considerably from their primary range in the southwestern United States. Diurnal rest sites, such as cavities in live and standing-dead trees, are an essential habitat element for ringtails and co-occurring mesocarnivores. Ringtails use diurnal rest sites as shelter during adverse weather conditions, refugia from predators, such as the co-occurring fisher (Pekania pennanti), and dens to raise young. Understanding the forest conditions associated with rest sites selected by ringtails can inform forest management practices. We fixed very high-frequency radio collars to 16 ringtails on the Hoopa Valley Indian Reservation in northern California to better understand the relationships between forest characteristics and fisher presence on ringtail rest site use. We found that ringtails were more likely to select rest sites in mature older forests compared to oak woodland and open areas and were less likely to select rest sites closer to perennial water sources. We did not detect an effect of fishers on the selection of rest sites. These results indicate that both late- and some early-seral forest conditions provide suitable habitat for ringtail rest sites and ultimately demonstrate that ringtails use a mosaic of seral stages in the forests of the Pacific Northwest.

Mound-Building Ants and Associated Termites on Goodale's Cutoff along the Oregon Trail – Bradford M. Kard, Stephen P. Cook

Hundreds of ant nest bare mineral soil mounds as well as ant plant litter 'thatch' mounds are distributed across the sagebrush-steppe prairie landscape on Goodale's Cutoff along the Oregon Trail near Arco, Idaho, adjacent to the northern boundary of Craters of the Moon National Monument and Preserve. U.S. Natural Resources Conservation Service personnel and local landowners wanted to determine if these ants were exotic invasive pests that could damage prairie pasture and grazing habitat or impact historic anthropogenic artifacts. Four species of native ants, Pogonomyrmex salinus, Formica limata, F. obscuripes, and F. ravida that are common on the Snake River Plain of Idaho were collected from different mounds. Another native ant, Solenopsis molesta, was foraging around the perimeter of one thatch mound. Additionally, a subterranean termite, Reticulitermes tibialis, common in the western U.S. and widespread within Idaho prairies and mountains was found foraging within both types of ant mounds. This study provides insight into ant and subterranean termite activity on the Snake River Plain.