Geology topics

Research about Washington

Source-linked reports with geographic coverage including Washington.

At least 73 records · Page 4Linked to original sources

USGS2025

Invasive African clawed frogs ( Xenopus laevis ) in Washington State: Status, response efforts, and lessons learned

The African clawed frog (ACF, Xenopus laevis ), which is indigenous to sub-Saharan Africa, is an aquatic invasive species known to have severe ecological impacts on native fauna when introduced into non-endemic regions. In 2015, ACFs were detected in Washington State, U.S. for the first time, and the species is now documented at three cities across western Washington: Lacey, Bothell, and Issaquah. We cataloged the known ACF occurrences, early management efforts, biological data about the frogs, and status of these invasive populations at the three sites from 2015–2023. The ACFs appear to be established in at least three watersheds in the Puget Sound region despite substantial effort at eradicating them at one site. Presence of ACFs in watersheds that lack surface connectivity implies independent introduction events, and the capture of frogs in multiple subbasins in the same watershed may reflect the potential for further spread. Because the ACF is nocturnal and otherwise behaviorally and visually highly cryptic, other established populations may go undetected. Where the ACFs are largely confined to stormwater ponds — as many of our current observations suggest — eradication may still be possible, though a substantial, focused effort would be required. In addition, significant refinement of eradication approaches will be needed to ensure effectiveness in topographically and vegetatively complex Pacific Northwest aquatic environments.

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USGS2025

Estuarine tidal cycles may preserve thermal refugia as global temperatures increase

Climate change is affecting coastal ecosystems worldwide as water temperatures increase, hydrologic regimes change, and sea levels rise. Consequently, estuaries risk declines in ecosystem functioning due to increasing temperatures and other hydrologic factors. Characterizing and predicting estuarine water temperature are challenging because these systems are highly dynamic. Statistical models have been used to accurately assess air temperature-water temperature relationships in lakes and streams but have not been effectively applied to tidally influenced ecosystems like estuaries. We used 6 years of continuous monitoring data from the Nisqually River Delta in Puget Sound, Washington, U.S.A., to parameterize and run a non-linear statistical model and generate spatially explicit model predictions. Our goal was to examine spatiotemporal patterns in estuarine water temperature and thermal refugia given current estimates of climactic change. The performance of the parameterized model was similar to that of non-linear stream temperature models (NSE = 0.76; RMSE = 2.34 °C). Scenarios incorporating forecasted high-emission air temperatures through the year 2100 (+ 7 °C) predicted a corresponding 3.55 ± 0.63 °C increase in average water temperatures; however, moderate and high rates of sea-level rise offset temperature increases by 3–20% and substantially reduced the amount of time temperatures exceeded the thermal stress threshold of 20 °C for juvenile salmon. These findings demonstrate how the effects of one climate stressor (sea-level rise) may offset another (temperature increases) to maintain thermal refugia for coldwater fishes. Similar exercises may allow managers to explore mitigation options like the planting of riparian vegetation or modified flooding regimes to further offset rising water temperatures.

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USGS2025

Submarine canyon sediment transport and accumulation during sea level highstand: Interactive seasonal regimes in the head of Astoria Canyon, WA

The majority of submarine canyons on Earth today do not directly intersect littoral or fluvial sediment sources, yet these systems are rarely studied. The shelf-incised head of Astoria Canyon receives sediment from the nearby Columbia River and is subject to energetic forcing from shelf and slope processes, making it an ideal site to evaluate the modern activity of canyons in high-stand sea level conditions. This study uses in-situ data from Astoria Canyon to identify the active sediment transport processes and patterns of accumulation in temperate canyon systems that are decoupled from their sediment sources during sea level highstand. Hydrodynamic data from a benthic tripod deployment in the head of Astoria Canyon shows that sediment resuspension and transport during summer is driven by internal tides and plume-associated nonlinear internal waves. Observations of shoreward-directed currents and low shear stresses (<0.14 Pa) along with sediment trap data suggest that seasonal loading of the canyon head occurs during summer. Nearby long-term wave data show that winter storm significant wave height often exceeds 10 m, driving shear stress capable of resuspending all grain sizes present within the canyon head. Swell events are generally concurrent with downwelling flows, providing a mechanism for episodic downcanyon sediment flux. Century-scale accumulation rates evaluated from sediment cores show slow accumulation in the upper canyon head, but rates progressively increase with depth to at least 300 m. The depositional environment in Astoria Canyon continues to respond to fluvial and oceanic forcing over an annual cycle. This study indicates that canyon heads can continue to function as sites of sediment winnowing and bottom boundary layer export even with a detached, shelf-depth canyon head.

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USGS2025

Mortality events in Yuma myotis (Myotis yumanensis) due to white-nose syndrome in Washington, USA

The impacts of white-nose syndrome (WNS) on many bat species in eastern North America have been well documented because of the length of time that the causative agent, Pseudogymnoascus destructans ( Pd ), has been present and the ability to monitor bat hibernacula in that region. However, the disease outcomes for bat species in western North America are less known because of the more recent arrival of Pd and the challenges associated with monitoring hibernating bat populations in parts of the western US. We report on mortality events involving Yuma myotis ( Myotis yumanensis ) bats at two locations in King and Benton counties, Washington, US, that were attributed to WNS during the late winters of 2020–21 and 2024, respectively. All bats that were grossly examined had depleted subcutaneous white adipose tissue, tested positive for the presence of Pd , had histopathologic lesions consistent with WNS, and did not exhibit evidence of other disease processes that may have contributed to death. Mortality was likely higher than what was documented because the locations of the Pd -contaminated hibernacula from which the bats originated were inaccessible or unknown and thus could not be surveyed. These findings indicate that Yuma myotis may be highly susceptible to WNS, and close monitoring is warranted to understand how WNS will affect population trends in this (and other) western bat species.

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USGS2025

Declining marine survival of steelhead trout linked to climate and ecosystem change

Species with complex life cycles, such as anadromous fish that perform spawning migrations between freshwater and the ocean, may be particularly sensitive to global change because freshwater and marine habitats experience distinct shifts in climate and ecosystem dynamics. Abundances of wild steelhead trout ( Oncorhynchus mykiss ) have declined across most of their range over the past 40–50 years. We examined whether declines in steelhead survival can be linked to changing climate conditions and species interactions. A novel hierarchical integrated population model that accounts for the species' complex life history was fitted to data from multiple wild steelhead populations on the Washington coast, U.S.A. The model estimates recruitment residuals and kelt survival rates as time-varying processes, which reflect annual variation in survival before and after first maturation. We found that survival rates of immature steelhead (recruits) and adult steelhead (kelts) have declined over time and that survival trends across populations were strongly associated with climate and ecosystem change, specifically summer sea surface temperature and pink salmon abundance in the North Pacific Ocean, the NPGO index and river flows. Including these drivers in the model reduced unexplained annual variation in shared recruitment and kelt survival anomalies and largely accounted for their negative long-term trends. Our findings provide evidence that rising temperatures and increased interspecific competition at sea have contributed to declines in steelhead survival over the last five decades. Considering projected warming and high pink salmon abundances in the ocean, steelhead will likely continue to experience low marine survival rates.

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USGS2025

Review of the Lake Washington Ship Canal and Ballard Locks model, Seattle, Washington, 2014–20

Executive Summary The Hiram M. Chittenden (Ballard) Locks and Lake Washington Ship Canal connect freshwater Lake Washington and saline Shilshole Bay of Puget Sound in Seattle, Washington. The locks and canal allow for ships to traverse this reach. Anadromous salmonids also migrate through, transitioning between saline and freshwater environments, and making use of a fish ladder at the locks when traveling upstream. WEST Consultants, Inc., constructed a two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) simulating flow, water temperature, and salinity for the Ballard Locks and the Lake Washington Ship Canal. An initial model was built for calendar years 2014–15, and the model was updated using a more recent and modern dataset for calendar years 2016–20. The U.S. Army Corps of Engineers requested that the U.S. Geological Survey review this model and its documentation to evaluate the technical aspects of its development and calibration. Findings from this review include the following: Overall, the Lake Washington Ship Canal CE-QUAL-W2 model was well-documented and constructed largely following typical model-development methods. The Lake Washington Ship Canal model was built with CE-QUAL-W2 model version 4.5, compiled and released by Portland State University in April 2021. CE-QUAL-W2 updates and improvements are regularly released with bug fixes and new features, so any model updates would benefit from the use of the most-recent software release. The model grid that represents the Lake Washington Ship Canal bathymetry was 9.2 kilometers (5.7 miles) long, matching the expected length of the waterway. The deepest model segments were near sampling site LLLW (Large Locks site) near the locks. Lake Union is reported to constitute most of the volume of the Lake Washington Ship Canal and is depicted as such in the model grid. The model includes several water outflows at Ballard Locks, including the large and small locks, a saltwater drain, a spillway, smolt flumes, and a fish ladder. Flows from the spillway, smolt flumes, and fish ladder were combined into one structure outflow in the model and assigned one withdrawal elevation from the Lake Washington Ship Canal. The smolt flume and spillway withdraw from the same elevation, but the fish ladder flow withdraws from a higher elevation in Lake Washington Ship Canal, and that flow could be separated into its own withdrawal. The model input files were created using the Coordinated Universal Time standard instead of the more typical choice of using local standard time. This is not incorrect, but sub-daily results would need to be converted to local time for science-communication purposes. The meteorological dataset had some unexpected anomalies, such as a baseline shift in the wind-speed dataset. Other nearby meteorological datasets could be used instead or used to correct the current meteorological inputs. The upstream boundary was configured with water-temperature data from a continuous monitor buoy in Lake Washington. The boundary salinity was set at 0 parts per thousand for the duration of the model simulation. A more realistic estimate of salinity at the upstream boundary could be constructed using data from the same buoy. Saline inflow at the downstream boundary of the Lake Washington Ship Canal model through lock exchanges at the large lock was included as a tributary in the model. Salinity and temperature inputs in this tributary at the large locks were set as constant values for the entire simulation. Saline inflow through the small lock was not included in the model because few data were available, and the input was likely to be small because of the smaller surface area and volume of the small lock relative to the large lock. The model did not include any flow, water temperature, or salinity inputs to the Lake Washington Ship Canal other than at the locks and at the upstream boundary. Any point sources, small tributaries, or stormwater inputs were omitted from the model. It is unclear whether this is a substantial omission relative to model results. Most model parameters were set as defaults or to reasonable values. However, the value of the WINDH parameter, the height of the wind speed measurement, was different than the height of the meteorological site. Compared to measured data, the model simulated water-surface elevations and water temperatures with reasonable accuracy. Differences in the modeled and measured salinities revealed some opportunities to improve the simulation of salinity, both baseline salinity and the salinity maxima in summer and autumn.

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USGS2025

The Benefits Knowledges Learning Framework: A tool for learning across diverse knowledge systems in ecosystem valuation

Sustainable and just environmental management depends on meaningful consideration of the plural values of nature, as they arise in association with diverse worldviews and understandings of well-being. To achieve value pluralism in decision-making, we must also attend to knowledge pluralism, in terms of recognizing the validity and decision relevance of a broader suite of knowledge forms that convey diverse understandings of well-being and benefit. In this article, we outline a social learning tool – the Benefits Knowledges Learning Framework – that supports expanded thinking about decision-relevant, actionable knowledge, and the associated spectrum of available opportunities to learn from these diverse knowledge forms across phases of decision-making. It does so through: 1) cultivation of reflexivity and mutual learning about the knowledge systems of diverse actors involved in the decision process; 2) identification of diverse benefits knowledge forms that are available to inform decision-making; and 3) identification of opportunities to learn from these knowledge forms. Diverse forms of benefits knowledge include both knowledge products (documentation) and knowledge practices (lived and embodied). The framework can be applied to retrospective case analysis to understand and learn from constraints and enabling factors in past decision processes. It can also be applied to assess on-going decision-making and identify current opportunities for improvement. The framework begins with a start-up phase that encourages those applying the framework to address any concerns raised by stakeholders and rightsholders and determine whether framework application is appropriate in a particular context.

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USGS2025

Shear surface undulations modulate clayey gouge strength and contribute to divergent landslide acceleration

Landslides display a spectrum of speeds for incompletely known reasons. Sliding occurs along slickensided undulatory shear surfaces within boundary shear gouge. Laboratory tests reveal that gouge shear strength generally decreases with finite cumulative displacement during relatively rapid failure and may increase or decrease with increasing shear rate; these behaviors can result in accelerating or decelerating landslide motion, which significantly affects consequent hazards. However, mechanisms responsible for such behaviors are poorly understood. We performed advanced ring shear strength testing that revealed such variable strength of a landslide near Oso, Washington, USA. We hypothesized that millimeter-scale undulations along shear surfaces caused the strength variability by imparting shear strength but while also modifying stresses that locally increase and decrease the typically considered particle-scale shear strength. We tested our hypotheses in the laboratory and with finite element soil deformation modeling. Lab results suggest that undulations contribute strength that decays with finite cumulative displacement. Modeling similarly reveals this, and that rapid shearing across undulations locally reduces effective normal stress by persistently elevating pore-water pressure and causing dilation. Consequent effects on strength differ by material with granular-rich, high-friction gouge losing strength and clay-rich, low-friction gouge losing little or gaining strength as shear rates increase. Ample testing by others reveals similar patterns. Hence, the propensity for gouge-controlled accelerating or decelerating failure may be estimated from simple index tests. Our findings on the effects of undulations reveal previously unknown mechanisms that may help to explain why some landslides reactivate catastrophically while others do not.

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USGS2025

Decadal-scale effects of a dam removal on channel geomorphology, sediment and large wood on the Elwha River, Washington, USA

The removal of Glines Canyon Dam on the Elwha River in western Washington, USA, from 2011 to 2014 introduced a 20-Mt pulse of stored sediment and logs into the downstream channel. We used terrestrial laser scanning, high-resolution orthoimages, and surveys of large wood (LW) and sediment grain-size distribution to quantify changes to the channel and LW in four different geomorphic settings spanning a 16-year period before, during, and after dam removal. The results provide insights into the role of site-specific geomorphology on the interplay among sediment size and supply, wood, and channel form in the aftermath of a dam removal. Sediment-size distribution, braiding index, and number of log jams rapidly reached new steady states. Other factors, such as channel sinuosity and log jam area, were still evolving six years after the dam was removed. The rate and type of river response was partially dictated by the geomorphic setting and the accumulation of LW. Complex reaches trapped more sediment and LW, initiating immediate changes in the channel count, position and lateral migration that continued to evolve through positive feedbacks. Single-channel sites experienced less initial erosion and deposition, but channel migration continued for years once it was underway. The post-dam sediment composition progressively shifted to a mixed size distribution midway between the armored cobbles when the dam was in place and the influx of primarily sand and fine gravel during dam removal. Reworking of sediment was most rapid in the first year after dam removal, especially at the site with the greatest channel complexity. The relation between log jams and channel divisions fundamentally changed. There were 11 log jams in the middle reach of the Elwha River downstream of Glines Canyon Dam, and all log jams associated with channel divisions occurred at the heads of stable, vegetated islands. During dam removal, the number of log jams rapidly increased to 86 and stabilized near that level in the post-dam period. While log jams on stable islands persisted, more were added at divisions around transient sediment bars, scattered across gravel bars, or outside of the active channel. Following a brief spike during dam removal, there was a net long-term increase of ∼10 % in the number of channel divisions associated with log jams. The sediment deposits, LW, vegetation, channel morphology and river discharge continued to cause adjustments within the fluvial system a decade after the start of dam removal. This state of greater variability could be the new equilibrium for years to come.

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USGS2025

Divergent trends in fluvial suspended-sediment concentrations following improved land-use practices, southwest Washington State

Improvements in logging practices since the mid-20th century are widely presumed to have reduced suspended sediment loads in streams across the Pacific Northwest. However, there have been few opportunities to directly assess this, particularly in larger rivers. We compare modern (2019–22) and historical (1960s) suspended sediment monitoring in three large, actively managed watersheds in western Washington with similar land-use histories. In the two watersheds draining the southern Olympic Mountains (Satsop and Wynoochee Rivers), modern sediment yields were around 300 t/km 2 /yr, two to three times lower than historical conditions. Most suspended sediment exiting these watersheds came from rolling terrain mantled by glacial deposits in the lower watersheds, not the steep headwaters. Modern sediment yields in the Chehalis River, draining the low-relief Willapa Hills, were lower (70 t/km 2 /yr), though this represented a 50 % increase relative to historical conditions. SSC-discharge relations in the Chehalis River were steady from 1961 to 1994, indicating this increase happened sometime after 1994. The Chehalis River headwaters were uniquely impacted by landsliding during a 2007 storm, though there is some evidence against that storm as the cause of the recent increase. Ultimately, improved land-use practices appear to have reduced suspended sediment loads in large rivers of the southern Olympic Mountains several-fold, consistent with prior findings in the western Olympic Mountains, primarily due to reduced sediment delivery from the lower watersheds. Countervailing SSC-discharge trends and lower yields in the Chehalis River underscore that background sediment delivery rates and sensitivity to land-use disturbance may vary substantially within a region.

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USGS2025

Simulating human behavior under earthquake early warning

Earthquakes are a rapid-onset hazard where advance planning and learning plays a key role in mitigating injuries and death to individuals. Recent advances in earthquake detection have resulted in the development of earthquake early warning (EEW) systems. These systems can provide advance warning to predetermined geographic regions that an earthquake is in progress, which may result in individuals receiving warning seconds before significant shaking is felt at their location. This additional time could allow individuals to take more effective protective actions during the immediate disaster. To demonstrate this, we created an agent-based simulation of a basic apartment that allowed us to randomly and repeatedly simulate an individual receiving and responding to an EEW message. The results of our preliminary simulation show that, in our study environment, earthquake early warning alerts have the potential to allow for sufficient time for individuals to take protective actions.

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USGS2025

Refining PAH and PCB bioavailability predictions in industrial sediments using source-fingerprinting, particle size, and bulk carbon, Puget Sound, Washington

Nearshore marine sediments in a Puget Sound, Washington industrial embayment had elevated levels of PAHs, PCBs and DDTs. Chemical fingerprints implicated nearshore sources including creosote, industrial oil and tar waste, and a landfill. Elevated concentrations were confined to an approximate 300-m shoreline buffer in the industrial waterfront, suggesting high site fidelity and limited along-shore or off-shore transport. Total PAH concentrations approximately doubled when including alkylated compounds. The industrial sediments often exceeded toxicity criteria; however, chemicals were likely less bioavailable than predicted, in part, due to assumed strong sorption to anthropogenic carbon like coal tar. Analyses of separated particle-size fractions showed that approximately half of PAHs were associated with particles greater than 500 μm, suggesting that a wide range of particle sizes are relevant to occurrence and transport. Predicted freely dissolved chemical concentrations in sediment pore water were unrealistically high using a bulk organic carbon sorption coefficient. When reduced to environmentally reasonable levels by applying a high-sorption partition coefficient applicable to contaminated sediments, predicted freely dissolved concentrations in some industrial sediments exceeded sublethal effect levels or surface water quality standards. Chemical assemblages predicted in the freely dissolved aqueous fraction, which is relevant for biotic uptake from water, shifted to predominantly low molecular weight as compared to sediment, highlighting the role of exposure pathways in bioavailability. Insights from chemical fingerprinting coupled with co-analysis of bulk carbon and grain size allowed refinement of bioavailability assessments of complex chemical mixtures in contaminated nearshore environments that are relevant for ecosystem health and restoration.

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USGS2025

Estimating predation of adult sockeye salmon by American white pelicans in the Columbia River using a state-space Bayesian approach

Adult sockeye salmon ( Oncorhynchus nerka ) migrate past the largest breeding colony of American white pelicans ( Pelecanus erythrorhynchos) in the Columbia River, USA. To investigate the magnitude of pelican predation on sockeye salmon, a state-space Bayesian model was used to estimate spatially and temporally explicit predation and survival probabilities, and to estimate the total number of salmon consumed by pelicans each year. Results show that pelican predation was a substantial source of salmon mortality in some years, with median predation probabilities ranging annually from 0.015 to 0.084, resulting in an estimate of 1328 to 47 265 fish consumed annually from 2014 to 2023. While there was evidence that predation probabilities were associated with the number of sockeye salmon returning to the Columbia River annually, there was no evidence that fish length was associated with susceptibility to predation. Additional research aimed at investigating how other biotic and abiotic factors influence sockeye salmon susceptibility to pelican predation are needed to broaden our understanding of predator–prey interactions and to determine to what degree predation limits sockeye salmon survival prior to spawning.

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USGS2025

DNA metabarcoding of biocrust lichen-forming fungi detects responses to disturbance and invasion

Biocrusts dominated by bryophytes and lichens perform important functions in dryland ecosystems but monitoring these communities can be cost prohibitive over broad scales. We explored DNA metabarcoding as a potential tool for monitoring biocrust lichen communities at a site in Washington (U.S.A.) that had already been surveyed for lichen diversity and community composition. We developed a DNA reference library using the internal transcribed spacer (ITS) region from specimens collected in the study area. We also visually estimated the abundance of lichen species or groups in 22 plots spanning a range of wildfire history and invasion by the exotic annual grass Bromus tectorum . At these plots, we collected bulk lichen community samples for metabarcoding using two approaches: small sample dishes and combined biocrust fragments collected using tweezers from all species observed. We used PacBio sequencing to simultaneously generate ITS barcode sequences for all lichen-forming fungi (LFF) present in the bulk samples, clustering similar sequences into operational taxonomic units (OTUs). Lichen communities detected visually and using DNA metabarcoding both captured a reduction of biocrust diversity and change in community composition related to the abundance of B. tectorum , suggesting that metabarcoding was able to identify the same dominant ecological pattern in biocrust lichens as visual sampling. The tweezer sampling approach captured on average 12.3 more OTUs than the dish approach and some taxa were more consistently detected by one approach or the other. After using the specimen DNA reference library to identify species associated with LFF OTUs, we determined that metabarcoding and visual sampling detected overlapping but different lichen species. Metabarcoding failed to detect common collected taxa, including: Arthonia glebosa, Candelariella spp ., Enchylium tenax, Lecanora muralis, Lecidella spp ., Leptochidium albociliatum, Massalongia carnosa, and Trapeliopsis glaucopholis. However, metabarcoding detected OTUs not visually observed in the genera Elixia, Lecanora, Lecanoropsis, Bacidina, Pyrenodesmia, Xanthocarpia, Trapelia, Verrucaria, and Verruculopsis . Furthermore, metabarcoding identified greater OTU diversity than expected within Diploschistes muscorum, Trapeliopsis bisorediata, and Trapeliopsis steppica . Our results suggest that metabarcoding alone or combined with visual methods could be a useful approach for monitoring biocrust lichen communities and their response to disturbance, invasion, and potential restoration.

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USGS2025

Living with wildfire in Chelan County Fire District #3, Chelan County, Washington: 2022 data report

Community wildfire readiness includes homeowner wildfire risk mitigation and wildfire evacuation preparedness. In 2021 and 2022, the Wildfire Research (WiRē) Center partnered with Chelan County Fire District #3 (CCFD #3) to learn how CCFD #3 can effectively engage with residents about preparing for a wildfire event and mitigating wildfire risk around the home. The CCFD #3 residents were responsive to the household survey (38% response rate). Respondents reported being aware of wildfire risk and having taken action to mitigate risk on their properties and prepare for evacuation. However, residents’ perceptions of property-level wildfire risk did not align with wildfire assessments conducted by trained assessors. Residents may benefit from financial assistance to support proper mitigation and educational outreach.

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USGS2025

Appendix B: Patterns of bull trout Salvelinus confluentus demography, life history, abundance, and trends in the Lewis River

Declines in the distribution and abundance of bull trout ( Salvelinus confluentus ) across much of the historical range in the Pacific Northwest region of Canada and the United States have been well documented (Post and Johnston 2002; Rieman et al. 1997). Recent estimates of population trends appear to vary considerably across regions with large numbers of migratory and resident populations exhibiting substantial declines in adult abundance (Al-Chokhachy et al. 2016; Kovach et al. 2018), whereas others remain stable or potentially increasing (Erhardt and Scarnecchia 2014; Meyer et al. 2014). For example, 61% of the core populations in Alberta, Canada, are considered declining, and 39% are stable or increasing (Alberta Sustainable Resource Development 2012). The variability in population status and trends highlights the importance of population-specific data. Much of our understanding of bull trout life history has stemmed from a few, well-studied populations, and continuing to improve our knowledge of the variability in life-history expressions (e.g., Starcevich et al. 2012) can support directing local and regional conservation efforts (sensu Schindler et al. 2010). Here, we consider the life history, demographic patterns, and assess potential threats for an adfluvial population of bull trout in the upper Lewis River basin in Washington, USA. We synthesized recent monitoring efforts and field studies to refine our understanding of bull trout life-history expressions (i.e., migration patterns), demographics, and genetic status. We further evaluated the potential threats of brook trout ( S. fontinalis ), a species that is not native to the Lewis River, but which was recently documented in bull trout monitoring efforts (Al-Chokhachy et al. 2024). Our specific objectives included evaluating: (1) trends in size structure of subadults and adult bull trout (2014 – 2024); (2) patterns of adult migration and life-history and climate drivers of migration patterns (2011 – 2024); (3) the within-year temporal patterns of bull trout and coho salmon ( Oncorhynchus kisutch ) spawning and superimposition of bull trout redds by spawning coho salmon (2024); (4) temporal trends in abundance for adult and juvenile bull trout from annual monitoring methods (2008 – 2024); and (5) the current (2024) extent of non-native brook trout in wetland habitat adjacent to Yale Lake.

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USGS2025

Wind River subbasin restoration: Annual report of U.S. Geological Survey activities January 2023 through December 2023

We sampled juvenile wild Oncorhynchus mykiss (Steelhead Trout) in headwater streams of the Wind River, WA, to characterize population attributes and investigate life-history metrics, particularly migratory patterns, and early life-stage survival. We used passive integrated transponder (PIT) tagging and a series of instream PIT-tag interrogation systems (PTISs) to track juveniles and adults. The Wind River subbasin is considered a wild Steelhead refuge by Washington Department of Fish and Wildlife (WDFW). No hatchery Steelhead Trout have been released in the Wind River subbasin since 1997, and hatchery adults are estimated at less than one percent of spawners in most years. Over twenty years of Steelhead Trout status and trend monitoring and research in the subbasin is contributing to understanding of population response to numerous restoration actions in the subbasin, including removal of Hemlock Dam from Trout Creek in 2009, which had an inadequate adult ladder and contributed to increased water temperatures. Data from our study, and companion work by Washington Department of Fish and Wildlife, are contributing to the Columbia Basin Fish and Wildlife Program (2008) Research, Monitoring, and Evaluation (RM&E) Strategy of Fish Population Status Monitoring. Specifically, this work addresses the sub-strategies of 1) Assessing the Status and Trends of Diversity of Natural Origin Fish Populations and Uncertainties Research regarding differing life histories of a wild Steelhead Trout population, 2) Assessing the Status and Trend of Adult Natural Origin Fish Populations, and 3) Monitoring and Evaluating the Effectiveness of Tributary Habitat Actions Relative to Environmental, Physical, or Biological Performance Objectives. During summer and fall 2023, we PIT-tagged 1,294 Steelhead Trout parr (age-0 and age-1), in the Trout Creek and upper Wind River watersheds. Age-0 parr were at high abundance due to a strong spawning run in 2023 (estimate of 814 adults from September snorkel survey compared to 22-year median of 450; Charlie Cochran, WDFW Fish Biologist, personal commun., 2022), but age-1 parr abundance was low following poor spawner numbers in 2022 (estimate of 159 adults from September snorkel survey). An additional 189 age-2 or older parr were tagged to provide fish for estimating detection efficiencies at PTISs. Steelhead Trout parr were recaptured and detected through repeat headwater sampling, smolt trapping, instream PTISs and Columbia River PIT-tag detection. We maintained and upgraded six instream PTISs to detect PIT-tagged Steelhead Trout parr, smolts, and adults, providing data for population assessments, and life-cycle research. Detection data from PIT-tagged adult Steelhead Trout at PTISs allow assessment of adult escapement to tributary watersheds within the Wind River subbasin. Adult Steelhead Trout detection efficiency estimates at our primary PTIS in Trout Creek have been greater than 99 percent during seven of the past nine years and have exceeded 97% at our primary PTIS in the Wind River during eight of the past nine years. Adult escapement estimates to tributary watersheds are helping evaluate the efficacy of the 2009 removal of Hemlock Dam from rkm 2.0 of Trout Creek, where it had potential negative effects on Steelhead Trout populations due to hydrologic impairment, increased temperatures, and adult passage issues because of an inadequate fish ladder. Detections at the instream PTISs have shown trends of age-0 and age-1 Steelhead Trout parr emigration from natal areas during summer and fall, in addition to the expected movement of parr and smolts in spring. Our data suggest that often most fish from a cohort that migrate downstream will do so at age-1 for additional rearing downstream of their natal areas. It is unknown if this is ingrained behavior or a result of lack of habitat capacity. We have estimated that from 15 to 56% of parr tagged as age-0 fish in headwater areas make downstream migrations at age-1 for additional rearing. We have estimated that up to 27% of Steelhead Trout parr, tagged as age-1 fish, make downstream migrations during fall: this is especially pronounced in the upper Wind River portion of the watershed. These findings raise questions about preferred parr rearing habitat and whether migrations are density- or habitat-quality driven, and answers to such questions are part of the long-term goals of this study as active and passive habitat restoration actions occur. Repeat sampling at sites in the subbasin within and between years has enabled assessment of juvenile Steelhead Trout growth patterns. Growth rates (relative change in weight) of age-0 PIT-tagged parr during summer have been similar across the subbasin, though slightly lower in the Trout Creek watershed. Summer growth rates have been lower for age-1 parr in the Trout Creek watershed than the upper Wind River watershed. Yearly relative growth was similar across the subbasin for both age-0 and age-1 tagged parr. Non-native Salvelinus fontinalis (Brook Trout) are present in the subbasin, chiefly the Trout Creek watershed, and repeat sampling provides an index of their prevalence. Mean percent-of-catch that is Brook Trout, at four sample sites in Trout Creek, has declined from the period 1998 – 2003 to the period 2011 – 2024. Percent-of-catch and number of Brook Trout at the Trout Creek sites from 2011 through 2022, though variable, have generally declined. Evaluation and planning of habitat restoration efforts are critical to ensure efficient use of money and resources. Assessing Steelhead Trout life history variation in the Wind River subbasin informs research and tracking of many populations and habitat restoration and water allocation planning. Movement of Steelhead Trout parr from natal areas to other rearing areas raises questions regarding juvenile abundance, origin, and habitat use within watersheds. Improved PTISs and focused PIT-tagging of age-0 and age-1 Steelhead Trout parr allow investigation of such questions. Detailed viable salmonid population and life-history data, such as that provided by PIT-tagging and instream PTIS networks inform fisheries policy and management and enable assessment of long-term effects of habitat restoration actions such as the removal of Hemlock Dam on Trout Creek and proposed major instream habitat restoration in the upper Wind River.

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USGS2025

Mammalian responses to select Type 3 Watershed Experiment prescriptions in the Olympic Experimental State Forest: A camera-based monitoring approach

The Type 3 Watershed Experiment is a landscape-scale management experiment designed to assess the ecological, economic, and social benefits of timber harvest and post-harvest management prescriptions in upland and riparian systems of the Washington Coast Range ecoregion. The experiment is being conducted on state trust lands in the Olympic Experimental State Forest (OESF), which are managed by the Washington Department of Natural Resources (WADNR). A wide variety of abiotic and biotic responses are being studied for the experiment, but no current studies include mammalian responses. The goal of this study is to use camera traps to assess patterns of medium and large mammal use of treatment blocks associated with the Type 3 Watershed Experiment, including the Complex Early Seral (CES) prescription and Variable Retention Harvest (VRH) prescription, in comparison to unharvested second growth forests. We are using a block design to assess responses of the medium and large mammal community to the CES and VRH prescriptions. Target taxa include Columbia black-tailed deer, Roosevelt elk, black bear, cougar, coyote, bobcat, fisher, and other medium sized mammals of interest. Mammalian use at the management prescription sites will be compared to use at the unharvested control sites (second growth forest stands). We will conduct an initial study in 2024─2025 for proof of concept after a pilot period of camera deployment. We anticipate that the cameras will be deployed continuously year-round for at least three years and possibly longer to assess longer-term patterns of use of these prescriptions. The project includes 48 cameras deployed evenly across CES, VRH, and control units. All our camera deployments are collocated at sites where avian monitoring is also occurring, and several also overlap with areas where the amphibian community is being surveyed, providing spatial linkages among different wildlife datasets. We will assess mammal community responses to forest management prescriptions using a variety of approaches. For the different prescriptions, we will examine the occurrence of a suite of species, measure species richness (alpha and beta diversity), estimate relative use, and quantify species persistence (i.e., the amount of time a species spends in a given prescription). We will estimate the influence of select habitat conditions on individual species use and on total species richness using mixed-effects models. The results of this study will provide estimates of initial responses of the mammalian community to the focal management prescriptions and serve as baseline data for long-term monitoring. This research will provide natural resource managers with a better understanding of how the mammalian community responds to and uses different types of habitats after timber harvest operations and will assess how those patterns change over time as vegetation develops under different silviculture prescriptions.

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