Fire ecology in oak shrublands is among the least well understood for Pacific Northwest habitats. Following the 2018 Klamathon Fire, we examined the first three years of post-wildfire plant community change and measured soil properties in shrubland dominated by shrub-form Oregon white oak (Quercus garryana) in Cascade–Siskiyou National Monument, Oregon. Based on temporal change and comparison with unburned areas, burned oak shrubland communities displayed resiliency and at least transient increases in some native plants apparently benefiting from wildfire. Via oak resprouting and other native plants increasing, total native cover rapidly recovered in burned areas by the second post-fire year to not differ (P > 0.05) from unburned areas. Native species richness (number of species∙25 m^-2) did not differ with burning any year while community evenness and diversity were usually highest in burned areas. Native plants associated with burned areas included the perennial grass blue wildrye (Elymus glaucus), the shrub Pacific serviceberry (Amelanchier alnifolia), and, most abundantly, forbs such as the perennial Scouler's hawkweed (Hieracium scouleri) and annuals such as slender clarkia (Clarkia gracilis). Cover of non-native plants on burned areas was not higher than on unburned areas within any year. After severe burning, the 0–5 cm mineral soil had the finest texture and highest bulk density. Overall, oak shrubland vegetation displayed rapid resilience to wildfire and native forbs at least transiently increased.

Seattle Public Utilities (SPU) has a history of conducting traditional fish surveys in urban streams of Seattle, Washington. Limited staff resources have reduced SPU's capacity to monitor fish, and environmental DNA (eDNA) was recognized as an alternative survey method that could potentially improve the efficiency and capacity of SPU-sponsored fish surveys. We performed spatiotemporal surveys of eDNA to assess occupancy and distribution of Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (O. kisutch), and Coastal Cutthroat Trout (O. clarkii clarkii) in Thornton Creek, Seattle, between October 2018 and December 2020. Peak Chinook and Coho eDNA detections occurred in October and October–November, respectively, coinciding with expected adult return time. Chinook and Coho eDNA was detected in May at the time when juveniles outmigrate through the Lake Washington basin. Coastal Cutthroat Trout eDNA was widespread and detected at high rates across seasons, reflecting their ubiquitous distribution. Results from multiscale occupancy modeling suggested that distance upstream affected site-level occupancy probabilities for adult Chinook, but not Coho. Model results also suggested that the probability of Coho and Chinook eDNA occurring in water samples was affected by survey year. Finally, model results suggested that the probability of detecting Chinook eDNA in PCR technical replicates was affected by survey year and collection day but detection of Coho eDNA was only affected by collection day. This study indicates eDNA surveys are effective for assessing distribution and occupancy of salmonids in Seattle's urban streams. Integrating eDNA surveys into urban stream monitoring programs can help alleviate the burden of limited assets facing many resource managers.

From British Columbia to northern California, coastal giant salamanders (Dicamptodon tenebrosus) are a dominant vertebrate predator in forested headwater streams. Though widespread, body condition and abundance of coastal giant salamanders can differ substantially among locations, provoking the question of which factors may influence this variation and to what degree habitat features versus biotic variables drive variability. In this study, we collected data on coastal giant salamander populations along with four biotic factors and eight abiotic factors across 24 different study streams adjacent to mature second-growth forests in western Oregon, USA. We used single and multi-parameter linear mixed-effects models to explore the factors individually and in combination to functionally represent alternative hypotheses accounting for variation in salamander biomass density, population density, and condition. We established a set of 25 models and employed Akaike's Information Criterion (AIC) selection for comparison. We expected food resources and the abundance of coastal giant salamander competitors to have comparable and complementary influences with stream habitat metrics. However, biotic metrics did not appear in our top models. Two abiotic variables, pool area and substrate size, best predicted the biomass and population densities of coastal giant salamanders across our study streams. Substrate size and pool area were negatively related to salamander density, in contrast to our expectations. Overall, our results suggest that habitat metrics in summer months influence the population density and biomass density of coastal giant salamanders in western headwater streams, and therefore habitat availability warrants particular consideration in conservation efforts.

We conducted a five-year study (2015–2019) of flower phenology and insect flower-foraging in Heather Meadows in the northern portion of the North Cascades in Washington State. We recorded 70 species of eudicot forbs and shrubs on seven transects at elevations ranging from 1,260 to 1,582 m. In a typical year, there was continuity of floral resources within each transect and across the elevational gradient for the duration of the growing season. Black huckleberry was a critically important forage resource for post-diapause queens as they established nests in spring, even as 98% of the meadow was under snow. Transects with the highest tree island cover had the largest number of foraging spring queens. The exceptionally early spring of 2015 made it a good analog of climate change predicted for this region toward the end of the century. In 2015, flowering was two to eight weeks early for a majority of species, while the duration of flowering increased for a few species and decreased substantially for others, leading to phenological reassembly. These findings preview the potential impacts of climate change on flowering plants and flower-foraging insects in mountain meadows in the Pacific Northwest and could help guide effective conservation.

Spirit Lake, in southwest Washington, USA, was changed as a result of the 1980 eruption of Mount St. Helens. The lake morphology was altered by debris flows and the water was sterilized of most living organisms. Trees felled by the lateral blast and subsequently washed into the lake comprise a floating log mat which now covers 20% of the lake's surface area, providing a novel substrate for benthic productivity. By investigating the succession in this volcanic landscape's rapidly recovering aquatic ecosystem, our research specifically addressed the following questions related to the role of the floating log mat and associated benthic periphyton on sedimentary inputs of organic material: (1) Do patterns of log mat occupancy and related deposition of benthic periphyton correlate to spatial variation in organic sedimentary inputs? (2) Has benthic productivity changed over the lake's 40-year history since the initial establishment of the log mat? To address our questions, we analyzed biological and geochemical data derived from sampling the floating logs, sediment traps in the water column, a set of shallow sediment samples, and two sediment cores in areas of differing log mat occupancy. We used carbon and nitrogen elemental concentrations and stable isotope values of sediment organics to estimate the relative contributions of organic source materials (phytoplankton, macrophytes, periphyton) and diatom assemblages to infer information about changes through time. We found that spatial trends in sources of sediment organics corresponded to patterns of floating log mat occupancy, with higher contributions of periphyton-derived biomass in areas with more frequent log presence. These results provide insight into the dynamic role of log mat-derived productivity in the ongoing recovery and evolution of the Spirit Lake ecosystem. Our findings also underscore the importance of understanding and managing coarse woody debris in oligotrophic lakes as a substrate for benthic primary productivity that supports the whole lake ecosystem.