Faculty Data and Research

Permanent URI for this collectionhttps://digital.lib.washington.edu/handle/1773/19721

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Native bee richness increases with wildfire burn severity in ponderosa pine forests.
(Forest Ecology and Management (Elsevier), 2026-01-31) Maust, Autumn; Gardner, Joel; Tobin, Patrick C.
Wildfires are increasing in frequency and severity in dry forests across western North America and have direct effects on forest structure and ecosystem services. One important service to monitor is pollination, which promotes plant-pollinator biodiversity and is critical for post-fire vegetative recovery. Because pollination services can vary by species and across spatial and temporal scales, understanding the effect of fire on pollinator populations informs conservation management and ecosystem restoration. Due to the known positive effects of fire on bees, including increased floral resources, nesting habitat, and light availability, we hypothesized that pollinator richness would increase with burn severity (measured with the Composite Burn Index) and decrease with burn age. We quantified native bee richness in the Okanogan-Wenatchee National Forest in Washington, USA at nine forested plots that burned in 2021, 2018, and 2015, or were unburned since 1968. Data were collected in 2021, 2022, and 2023 biweekly from April to August using blue vane and pan traps. Our findings suggest that native bee genus richness was driven by the interaction between burn severity and burn age. Study areas that had recently burned at higher severities had greater bee genus richness. Furthermore, the proportion of above ground nesting bees in landscapes 1-8 years post-fire was greatest at sites that burned with moderate fire severity and had more available nesting habitat. Our findings suggest that mixed-severity fire in ponderosa pine landscapes promotes native bee biodiversity.
Citizen science data reveals winter warming delays cherry bloom in the Pacific Northwest, USA
(John Wiley & Sons Ltd, 2025-06-17) Maust, Autumn; Bradshaw, Michael J.; Braun, Michelle; Kim, Soo-Hyung; Tobin, Patrick C.
We monitored cherry bloom date on the University of Washington campus, Seattle, USA, in three flowering cherry species and cultivars to develop a predictive model for estimating bloom, and to quantify changes in bloom date in Somei-yoshino cherry (Prunus x yedoensis) between 1966 and 2024. We worked with citizen scientists to record bloom date, and for Prunus x yedoensis, bloom phases, using ArcGIS Field Maps between 2012 and 2024. We also examined newspaper archives to reconstruct the observed bloom date for Prunus x yedoensis prior to 2012. We used a published modeling framework to develop species- and cultivar-specific models to predict bloom. We observed different thresholds for chill and heat requirements across flowering cherry species and cultivars, and general congruence between observed and model-predicted bloom dates for each. Using the longer time series in Prunus x yedoensis, we observed that warmer winters slowed the accumulation of required chill units, while warmer springs led to required heat units accruing more rapidly. The net effect of warming winters and springs resulted in a delay in the bloom date of Prunus x yedoensis by ~2 days per decade between 1966 and 2024. Shifts in the bloom date of flowering plants could result in phenological asynchrony with pollinators, with cascading effects across ecosystems. Further research is needed to understand the complex responses of flowering plants to shifting climatic conditions.
Coding Manual for Adolescent-Nature Interactions at a Youth Group Home
(2025-01) Dunker, Chrystal L.; Gray, Carly E.; Kahn, Peter H., Jr.
This technical report provides our coding manual – our systematic method to code qualitative photovoice data – from a study of nature interactions supporting coping and resilience among adolescents with histories of trauma living in a youth group home. Other authors on this study (but not on this coding manual) include Jean Kayira (SUNY College of Environmental Science and Forestry) and Elizabeth McCann (Department of Environmental Studies, Antioch University, New England). Using the interaction pattern method detailed in this coding manual, we coded interview data from 12 adolescents about their meaningful nature interactions. A total of 1212 (Level 1) IPs were coded in these data from the participant’s interviews and categorized into 62 Level 3 IPs such as viewing nature from a different vantage point, moving along the edges of nature, foraging or harvesting edibles to eat or drink, experiencing periodicity of nature, or experiencing nature with others. This study introduced an Interaction Pattern Approach (IPA) as a means to explore how meaningful nature engagement fosters coping and resilience in adolescents with histories of trauma. This methodology centers on Human-Nature Interaction Patterns (IPs) and applies a consensus coding process to discern the links between IPs and understandings of resilience. This study resulted in seven themes labeled, “Coping and Resilience Domains” which are supported by 37 subthemes labeled, “Strengths.” This technical report provides open access to our core intellectual qualitative work on this project, and can be used by others seeking to employ an interaction pattern approach for studies relating to coping and resilience, or more generally seeking to characterize people’s interactions with nature. While this technical report focuses on characterizing the IPs from interview data and testing for reliability, a more detailed accounting of the consensus coding process for IPs and coping and resilience can be found within the lead author’s doctoral dissertation, “Nature Interaction Assists with Coping and Resilience: An Interaction Pattern Approach with Adolescents with Histories of Trauma in a Youth Group Home.”
Evaluation of Trapping Schemes to Detect Emerald Ash Borer (Coleoptera: Buprestidae)
(Oxford University Press on behalf of Entomological Society of America, 2021) Patrick C. Tobin; Brian L. Strom; Joseph A. Francese; Daniel A. Herms; Deborah G. McCullough; Therese M. Poland; Krista L. Ryall; Taylor Scarr; Peter J. Silk; Harold W. Thistle
Management responses to invasive forest insects are facilitated by the use of detection traps ideally baited with species-specific semiochemicals. Emerald ash borer, Agrilus planipennis Fairmaire, is currently invading North American forests, and since its detection in 2002, development of monitoring tools has been a primary research objective. We compared six trapping schemes for A. planipennis over 2 yr at sites in four U.S. states and one Canadian province that represented a range of background A. planipennis densities, canopy coverage, and ash basal area. We also developed a region-wide phenology model. Across all sites and both years, the 10th, 50th, and 90th percentile of adult flight occurred at 428, 587, and 837 accumulated degree-days, respectively, using a base temperature threshold of 10°C and a start date of 1 January. Most trapping schemes captured comparable numbers of beetles with the exception of purple prism traps (USDA APHIS PPQ), which captured significantly fewer adults. Trapping schemes varied in their trap catch across the gradient of ash basal area, although when considering trap catch as a binary response variable, trapping schemes were more likely to detect A. planipennis in areas with a higher ash component. Results could assist managers in optimizing trap selection, placement, and timing of deployment given local weather conditions, forest composition, and A. planipennis density.
The State of Climate Adaptation Science for Ecosystems in the Northwest U.S.
(2024-10) Fusco, Emily; Raymond, Crystal
Native solitary bee reproductive success depends on early season precipitation and host plant richness
(Springer, 2023) Tobin, Patrick C; Westreich, Lila R; Westreich, Samuel T
Spring-emerging bees depend upon the synchronized bloom times of angiosperms that provide pollen and nectar for offspring. The emergence of such bees and bloom times are linked to weather but can be phenologically mismatched, which could limit bee developmental success. However, it remains unclear how such phenologically asynchrony could affect spring-emerging pollinators, and especially for those that forage over a relatively short time period. We examined the relationship between weather and host plant selection on the native spring-foraging solitary bee, Osmia lignaria, across three years at urban and rural sites in and around Seattle, Washington. We used community science weather data to test the effects of precipitation, wind, and temperature on O. lignaria oviposition and developmental success. We also collected pollen data over two distinct foraging periods, early and late spring, and used Next-Generation Sequencing to identify plant genera from pollen. Among the weather variables, precipitation during the early foraging period adversely affected larval developmental success and adult bee emergence success, but not oviposition. Using DNA metabarcoding, we observed that increases in the number of plant genera in pollen increased adult emergence in both foraging periods, but not oviposition or larval development. We also observed that foraging bees consistently visited certain genera during each foraging period, especially Acer, Salix, and Rubus. However, pollen collected by O. lignaria over different years varied in the number of total genera visited, highlighting the importance of multi-year studies to ascertain bee foraging preferences and its link to developmental success.
Microbial community structures in family anaerobic digesters reveal potentially differing waste conversion pathways
(2023-10-12) Gough, Heidi L.; Kargol, Abigail; Beck, David A. C.; Therrien, Benjamin G.; Dahal, Bed Mani; Marsolek, Michael D.
Family-scale rural digesters are widely implemented in Nepal for waste management, resource recovery, and environmental stewardship for distributed communities. However, there is little documentation on the microbial community structures in real-world family farm digesters. This work compared microbial community structures in four family digesters to a near-by municipal digester. Included in the family digesters was a high-altitude family digester located on Mt. Everest in Mosi, Nepal (2,634 m elevation). Differences in the community structures included the prevalence in family digesters of Bathyarchaeota MGC-6. MCG-6 is an archaeal population putatively involved in autotrophic acetate generation and conversion of cellulose to sugars. Additionally, Rikenellaceae DMER64, a population thought to degrade sugars, was more prevalent in the family digesters. The ratio of Methanothrix to hydrogenotrophic methanogens was higher in the family digesters. Additionally, the dominant species of syntrophic hydrogen-producing bacteria differed. Syntrophobacter and Syntrophomonas species, documented for their critical roles in waste activated sludge digesters, were not detected. In conclusion, observed differences in microbial community composition suggested a capacity to support different substrate conversion pathways and a major role of Archaea beyond methanogenesis among the studied digesters.
Roadside Vegetated Filter Strips to Simultaneously Lower Stormwater Pollution Loadings and Improve Economics of Biorefinery Feedstocks
(2023-10-12) El-Husseini, Hisham; Chowyuk, Amira N.; Gustafson, Richard R.; Gough, Heidi L.; Bura, Renata
Roadside vegetated filters strips (VFSs) reduce roadway runoff pollution by intercepting stormwater and reducing pollutant loads. VFS maintenance and operating costs can be reduced by designing the VFSs to serve as sites for production of marketable biomass. This biomass can provide feedstock for the emerging bioeconomy producing renewable fuels and biobased chemicals and products. Economic evaluation is needed to quantify the benefit of combining VFS with bioenergy biomass production. This evaluation requires a place-based approach to quantify availability of land, transportation costs, and benefits to sensitive habitats. We evaluated roadside land, within the state right-of-way, in Western Washington, to determine the total area available for implementing VFSs. These data were then used to estimate the volume and cost, of biomass produced on the filter strips, and the resultant reduction in pollutants emitted through highway runoff. The analysis showed that up to 5,600 hectares were available for roadside VFSs that would be within transportation distance of the theoretical biorefinery location. This space could produce up to 97 dry Gg per year of poplar biomass. The resulting reduction in biorefinery feedstock cost was up to $24 per dry Mg compared to biomass from dedicated tree farms. The results showed that combining roadside poplar with traditional dedicated poplar feedstocks can reduce the feedstock cost of the biorefinery from $76 to $67 per Mg for a biorefinery processing 150 Gg biomass per year. Environmental impact analysis showed that within the study area half of urban roadways and one-third of rural roadways in highly sensitive aquatic areas were amenable to VFS. Construction of VFS in these amenable areas would reduce total loadings to sensitive aquatic areas in urban areas by 26% for TSS, copper, and zinc, and by 10% for phosphorus, and nitrogen and by 21% for lead. The impact for rural sensitive areas was even greater where the VFS had potential to reduce total loadings to sensitive aquatic areas by 38% for TSS, copper, and zinc, by 15% for phosphorus and nitrogen, and by 31% for lead. This research showed an approach combining geographic information system (GIS) mapping and economic analysis to document simultaneous evaluation of cost and environmental benefits when considering use of non-traditional land for bioenergy crop production.
Bacterial and Fungal Symbionts in Pollen Provisions of a Native Solitary Bee in Urban and Rural Environments
(Microbial Ecology (Springer Nature), 2023) Tobin, Patrick; Westreich, Lila; Westreich, Samuel
Among insects, symbionts such as bacteria and fungi can be linked to their physiology and immature development, and in some cases are part of a defense system against parasites and diseases. Current bacterial and fungal symbiont associations in solitary bees are understudied, especially in the Pacific Northwest region of the United States. We collected pollen provisions from the native spring-foraging solitary bee, Osmia lignaria Say, across two distinct foraging periods over two years at 22 sites along an urban-to-rural gradient in western Washington. We then used Next-Generation Sequencing to identify bacterial and fungi within pollen provisions, and assessed the effect of their richness and diversity on O. lignaria larval development success and adult emergence. We detected a significantly positive relationship between bacterial diversity in pollen with O. lignaria larval developmental success, and higher bacterial richness and diversity during the later foraging period. Fungal generic richness and diversity decreased with increasing plant richness. Although neither was associated with O. lignaria developmental success, we did detect Ascosphaera spp. that are known to be pathogenic to O. lignaria and other bee species. Neither bacterial or fungal richness or diversity was affected by site type when classified as urban or rural. This study provides new information on bacterial and fungal symbionts present in pollen provisions of a native solitary bee when foraging across urban and rural areas of the Pacific Northwest.
Time-lapse imagery from eastern Washington, U.S.
(2022) Breen, Catherine; Hentati, Yasmine; Prugh, Laura
We present a time-lapse camera dataset for snow monitoring from eastern Washington, U.S.A. Eight time-lapse cameras facing a red pole 3-5 m away from the camera were installed between December 2020 and May 2021. Cameras were set to take an image every day at 12 PM PT. The sites spread an elevational gradient and contain both in- and out-of canopy locations. The dataset is organized with one folder of .jpeg images for each camera, along with a .xlsx file for site metadata, including latitude, longitude, percent of canopy cover, elevation (m), aspect, slope, and terrain type. Snow can be converted into snow depth by finding the length of the pole in pixels in each image and converting to centimeters using a conversion from the total length of the pole in cm/pixels. The cameras coincide with a wolf home range, making this data set ideal for testing hypotheses about how snow processes may be affecting predator-prey interactions, wildlife movement, and general trends for snow in an area where observations are sparse and limited.
Coding Manual for: Modeling Child-Nature Interaction in a Forest Preschool
(University of Washington The Human Interaction with Nature and Technological Systems Laboratory Department of Psychology & University of Washington School of Environmental and Forest Sciences, 2022-05-08) Weiss, Thea; Kahn, Peter H, Jr.; Lam, Ling-Wai; Koch, Taylor; Carrington, Kayla; Ling, Honson; Kohring, Peter Kai; Ho, Cassie; Lev, Elizabeth
There is increasing evidence that interaction with nature provides substantial benefits to the mental and physical development of children. While children’s time spent outdoors has declined substantially in recent decades, nature-based education programs like Fiddleheads Forest preschool in Seattle allow children to engage with nature in a supportive learning environment. The goal of this research was to begin to develop a model of child-nature interaction in a specific outdoor nature learning environment. To accomplish this, we systematically analyzed child-nature interaction through characterizing its essential features in the form of interaction patterns: the functional units of human interaction with the relevant physical characteristics that nature affords. Using a randomized time-sampling methodology, we collected video recordings of child-nature interaction and coded this data by means of an interaction pattern analysis framework. This technical report provides the coding manual used to systematically code each participant’s behavioral interactions. By a coding manual, we mean a document that systematically explains the process used to formally code the video data. Our goal is to present this manual such that, as part of an ongoing iterative scientific process, it can be used and modified by others interested in investigating the development and significance of children’s interactions with the natural environment.
Historical Avifaunal Change and Current Effects of Hiking and Road Use on Avian Occupancy in a High Latitude Tundra Ecosystem
(IBIS, 2022) Meeker, Avery; Marzluff, John; Gardner, Beth
Tourism is increasing in tundra ecosystems across the world, yet its influence on bird communities and its interaction with other drivers of change is poorly known. To help fill this gap, we paired an interview-based survey of eleven people with local knowledge of Denali National Park and Preserve, with an occupancy study of 15 bird species in relation to road proximity, traffic volume, and hiking. Interviewees noted declines in American Golden Plover, Arctic Tern, Long-tailed Jaeger, and Northern Wheatear over the past five decades. Our occupancy study confirmed these reports as we detected no Arctic Terns, few Northern Wheatears, and found both plovers and jaegers to be sensitive to hiking. Occupancy of tundra and shrub habitats by American Golden Plover, American Tree Sparrow, Lapland Longspur, Long-tailed Jaeger and Willow Ptarmigan declined with increasing hiking intensity. We found that occupancy probability of tundra by Horned Lark increased, while that of the shrub-tolerant Wilson’s warbler decreased, with distance from the Park Road. Detection of species varied based on survey length, noise, start time presence of a trail, and date. The knowledge gained from this study reveals a loss in avian diversity over the past few decades that has the potential to cause a shifted baseline syndrome, and ongoing threats of hiking to sensitive tundra-breeding birds. Park managers should seek to balance human recreation with the needs of sensitive tundra-breeding birds to further protect species of conservation concern. This may be done by not building new trails in tundra, limiting access to tundra hiking areas during the early breeding season, reducing the spatial extent of hiking by improving maintained trails and designating a single, maintained path in areas with multiple unofficial hiking tracks, educating tourists about tundra nesting birds, and closing especially important nesting areas to the public.
An observational analysis of Canada jay foraging and caching ecology in Denali National Park and Preserve-data
(2021) Swift, Kaeli; Marzluff, John; Williams, Emily
Arctic wildlife are among the globe’s most vulnerable species to climate change. Canada jays are generalist residents of northern boreal forests, and like many other winter-adapted animals, scatter hoard food to insulate against food scarcity during long winters. Unlike most scatter-hoarders, however, Canada jays primarily cache perishable food, rendering their caches more susceptible to climate-change induced degradation and loss. Here we use a mostly non-invasive approach to document Canada jay foraging ecology, including the types of food acquired, foraging and caching rates, and cache longevity and loss, among a population in interior Alaska. We also tested for any associations between foraging and caching rates with reproductive metrics to assess possible relationships among food and productivity. We found that Canada jays have a varied diet that changes seasonally, and responded to a record-setting warm spring by directing foraging efforts away from cache recovery towards the emergence of fresh food. We did not find evidence for relationships between foraging and caching rate with reproductive output, possibly owing to small sample sizes. We found that caches were recovered quickly (<3w) and frequently lost to conspecifics, and interestingly, to heterspecific competitors as well. Our study suggests that Canada jays may be better poised to respond to changes in cache integrity and food availability than has been previously recognized.
Brain activity underlying American crow processing of encounters with dead conspecifics
(2019) Swift, Kaeli; Marzluff, John; Templeton, Christopher; Shimizu, Toru; Cross, Donna
Animals utilize a variety of auditory and visual cues to navigate the landscape of fear. For some species, including some corvids, dead conspecifics appear to act as one such visual cue of danger, and prompt alarm calling by attending conspecifics. Which brain regions mediate responses to dead conspecifics, and how this compares to other threats, has so far only been speculative. Using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) we contrast the metabolic response to visual and auditory cues associated with a dead conspecific among five a priori selected regions in the American crow (Corvus brachyrhynchos) brain: the hippocampus, nidopallium caudolaterale, striatum, amygdala, and the septum. Using a longitudinal, fully balanced approach, we exposed crows to four stimuli: a dead conspecific, a dead song sparrow (Melospiza melodia), conspecific alarm calls given in response to a dead crow, and conspecific food begging calls. We find that in response to observations of a dead crow, crows show significant activity in areas associated with higher-order decision-making (NCL), but not in areas associated with social behaviors or fear learning. We do not find strong differences in activation between hearing alarm calls and food begging calls; both activate the NCL. Lastly, repeated exposures to negative stimuli had a marginal effect on the subjects’ sensitivity in response to control stimuli, suggesting that crows might quickly learn from such experiences.
Climate classification, contemporary active-fire reference areas, and structural measurements for the Sierra Nevada, California
(2019) Jeronimo, Sean; Kane, Van; Franklin, Jerry
Occurrence and variability of tactile interactions between wild American crows and dead conspecifics
(2017-11-29) Swift, Kaeli N.; Marzluff, John
Breeding Dispersal by Birds in a Dynamic Urban Ecosystem
(2016-11-29) Marzluff, John
This excel file includes raw data on dispersal distance of urban birds in the Seattle, WA, USA area.
Calibrating vascular plant abundance for detecting future climate changes in Oregon and Washington, USA
(ECOLOGICAL INDICATORS, 2010) BRADY, TIMOTHY; MONLEON, VICENTE; GRAY, ANDREW
We propose using future vascular plant abundances as indicators of future climate in a way analogous to the reconstruction of past environments by many palaeoecologists. To begin monitoring future short-term climate changes in the forests of Oregon and Washington, USA, we developed a set of transfer functions for a present-day calibration set consisting of climate parameters estimated, and species abundances measured, at 107 USDA Forest Service FIA (Forest Inventory and Analysis) Phase 3 plots. For each plot, we derived climate estimates from the Daymet model database, and we computed species abundance as quadrat frequency and subplot frequency. We submitted three climate variables (mean January temperature, MJAT; mean July temperature, MJUT; and mean annual precipitation transformed to natural logarithms, MANPt) to canonical correspondence analysis (CCA), and verified their importances in structuring the species frequency data. Weighted averaging-partial least squares regression (WA-PLS) provided the means for calculating six transfer functions. In all cases, based on performance statistics generated by leave-one-out cross-validation, we identified two-component WA-PLS models as the most desirable. The predictive abilities of our transfer functions are comparable to, or better than, those reported in the literature, probably due both data quality and statistical considerations. However, model overfitting as a result of spatial autocorrelation remains a possibility. The large errors associated with our MJAT transfer functions connote that even the highest amount of change in mean January temperature predicted for Oregon and Washington for 2010-2039 would be indistinguishable from current conditions. The higher predictions indicate that our MJAT transfer functions may be able to track climate changes by the 2040s. Our MJUT transfer functions can detect change in mean July temperature under the highest projection for 2010-2039. Our MANPt transfer functions will be of limited use until the 2070s, given the predictions of only slight changes in mean annual precipitation during the early part of the twenty-first century. Our MJAT and MANPt transfer functions may prove useful at the present time to verify relative climatic stability. Because the predicted climate values sometimes deviate substantially from the observed values for individual plots, our transfer functions are appropriate for monitoring climatic trends over the entire Pacific Northwest or large regions within it, not for assessing climate change at individual plots.
The significance of population successional status to the evolution of seedling morphology in Pinus contorta var. latifolia (Pinaceae)
(Madroño, 2001) Brady, Timothy
A greenhouse study of lodgepole pine (Pinus contorta var. latifolia) seedlings tested the hypothesis that the successional role of a population, because of its influence on selection, partly determines autecological evolution. Seeds came from seral, climax, and persistent populations in the Blue Mountains of NE OR and SE WA. Indeed, greater

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