About

I’m a research professor in the Department of Biology at the University of Washington and based full-time at Friday Harbor Labs. When I’m not teaching or out in the field, I also serve as the Associate Director for the College of the Environment at UW. My academic interests focus on marine intertidal ecology, including plant-herbivore interactions, the classification, long-term monitoring, and maintenance of biodiversity of intertidal habitats, and invertebrate functional morphology.

Research topics

• Ecology
• Biology
• Geography
• Fishery
• Environmental science
• Botany

Selected publications

• Friday Harbor laboratories: experimental biology at the water's edge

  Journal of Experimental Biology · 2026-03-01

  articleSenior author

  The University of Washington's marine field station, the Friday Harbor Laboratories (FHL), has been a center for diverse biological research for over 100 years. The facility is a complete mini-campus with housing and dining facilities. Experimental biologists visit from all over the world to focus intensively on their research efforts, an endeavor that is made possible by state-of-the-art equipment and biologically diverse local habitats. FHL also offers courses and short workshops that use local marine organisms and common-use equipment to train the next generation of scientists in fields as diverse as natural history to evolutionary development of invertebrates to biomechanics of fishes. Particularly strong areas of focus over the long history of FHL include comparative biomechanics (of everything from seaweed to sharks), developmental biology, neurophysiology and other physiology, genomics and marine ecology. Recent interactions of FHL researchers with other specialists ranging from engineers to restoration practitioners keep FHL on the cutting edge of research.

  PublisherDOI

• A case study on the effects of nutrient pollution on green tides

  SSRN Electronic Journal · 2026-01-01

  preprintOpen access1st authorCorresponding
  PublisherDOI

• Micro‐Refuges or Ecological Traps: Context‐Dependent Effects of Rock Pools on Intertidal Biodiversity Across Latitudes

  Global Ecology and Biogeography · 2026-02-01

  articleOpen access

  ABSTRACT Aim We investigated how local‐scale environmental heterogeneity influences biodiversity patterns across broad biogeographic gradients, using intertidal microhabitats as a model system within one of the most environmentally stressful ecosystems on Earth. Location Intertidal habitats at 26 locations (two rocky shore sites per location) across six continents, spanning 98° of latitude (38°S to 60°N). Time Period 2019–2022. Major Taxa Studied Algae, sessile and mobile invertebrates. Methods We compared biodiversity and thermal environments across contrasting microhabitats (rock pools and adjacent emergent rock) along a latitudinal gradient, sampling during environmentally ‘milder’ and ‘harsher’ periods. Biodiversity was quantified using multiple richness metrics (mean, total, unique taxa) and functional diversity. Results Microhabitat differences strongly influenced biodiversity patterns across latitude. Rock pools consistently supported higher taxonomic and functional diversity than emergent rock, irrespective of sampling period, reflecting their ability to buffer thermal extremes, particularly under harsher conditions. Mean species richness exhibited a non‐linear, s‐shaped latitudinal pattern, with lowest values near the equator and higher richness at mid‐latitudes, diverging from classical Latitudinal Diversity Gradient expectations. Biodiversity differences between microhabitats were greatest in temperate regions and diminished at low latitudes, where extreme conditions constrained diversity across habitats. Main Conclusions Local environmental heterogeneity can substantially modify, and in some cases obscure large‐scale biodiversity patterns. By mediating exposure to environmental stress, intertidal microhabitats provide insight into how fine‐scale variability interacts with latitudinal stress gradients to shape biodiversity distributions. Incorporating microhabitat variability into biogeographic frameworks is important for understanding global biodiversity patterns and predicting ecological responses to climate change.

  PublisherOA PDFDOI

• Marine infrastructure supports a deepwater benthic assemblage in Puget Sound, WA

  Marine Biology Research · 2026-03-23

  article1st authorCorresponding
  PublisherDOI

• Population genomics reveals strong impacts of genetic drift without purging and guides conservation of bull and giant kelp

  Current Biology · 2025-01-17 · 17 citations

  article
  PublisherDOI

• Location and natural history are key to determining impact of the 2021 atmospheric heatwave on Pacific Northwest rocky intertidal communities

  Frontiers in Marine Science · 2025-01-29 · 1 citations

  articleOpen access

  Introduction In late June 2021, the Pacific Northwest region of the United States and Canada experienced an unprecedented atmospheric heatwave that co-occurred with one of the lowest day-time tide series of the year. Several consecutive days of air temperatures 10-20°C above normal, coupled with mid-afternoon low tides proved deadly for many rocky intertidal organisms, which live at the margin of land and sea. Methods To assess short (weeks) and longer-term (1 year) impacts of the heatwave on rocky intertidal communities, we used long-term monitoring data collected annually at 16 sites throughout Washington State. Results and discussion Our findings indicate that impacts were most severe at sites within the Salish Sea region of WA, where peak low tides occurred during the hottest, mid-afternoon hours. Focal species assemblages at Olympic coast sites, where low tides occurred in the morning, were largely spared. In addition, while the heatwave was associated with substantial short-term changes in acorn barnacle, rockweed, and California mussel assemblages, lasting impacts (1 year) were only observed in the mussel assemblage at the one Salish Sea site where this species is common. These findings will aid in forecasting both short-term and longer lasting impacts of future heatwave events and help direct potential mitigation efforts to regions and species assemblages where impacts will likely be greatest.

  PublisherOA PDFDOI

• Functions of coastal feeder bluff systems: Implications for prioritizing protection and restoration

  PLoS ONE · 2025-10-15

  articleOpen accessCorresponding

  Actively eroding cliffs, known as feeder bluffs, are important sources of sediment for coastal beaches. When shorelines have artificial armor, natural beach sediment processes can be disrupted. A recent management tool in the Salish Sea, WA, USA prioritizes efforts with high potential benefit of restoration (armor removal) or protection (preventing armor construction) to nearshore sediment supply. We conducted field sampling at 20 beaches identified as the highest or lowest priorities for restoration or protection, so we could examine local ecological and physical functions, in addition to potential landscape benefits. We sampled parameters spanning the top of the bluff to the low shore, and evaluated a total of 30 metrics including riparian vegetation, invertebrate assemblages, logs, beach wrack, fish abundance and behavior, surface epifauna and algae, beach and bluff characteristics, and sediment size and sorting. For analyses, we calculated an average score of beach function for each of four treatments: "Protect High" (unarmored, ranked as high management priority), "Protect Low" (unarmored, ranked low), "Restore High" (armored, ranked high), and "Restore Low" (armored, ranked low). Protect High and Low treatments were equivalent in local beach function, and both scored over twice as high as Restore treatments. Restore High scored only slightly higher than Restore Low, indicating a consistent degradation caused by armoring on bluffs with variable sediment source potential. Statistical models revealed that overall beach function may be largely driven by upper beach metrics including wrack, logs, and overhanging vegetation. Metrics for geomorphology and lower beach organisms were more variable, likely due to differences in geographical region and distance from the bluff. Our results indicate that beaches with natural unarmored bluffs have the highest level of localized ecological function regardless of the level of potential sediment supply, and restoring sediment supply processes at beaches with armored bluffs could double their ecological function.

  PublisherDOI

• Micro-refuges or ecological traps: context-dependent effects of rock pools on intertidal biodiversity across latitudes

  Open MIND · 2025-10-05

  dataset

  Biodiversity is unevenly distributed across the Earth. At very large spatial scales, the decline in species richness from the tropics to the poles, the Latitudinal Diversity Gradient (LDG), remains one of the most widely recognized patterns in ecology. We investigated how local-scale environmental heterogeneity influences biodiversity patterns across broad biogeographic gradients, using intertidal microhabitats (rock pools and adjacent emergent rock) as a model system within one of the most environmentally stressful ecosystems on Earth. This Dryad dataset compiles standardized biodiversity and microclimate observations from rocky intertidal habitats at 26 locations in 21 countries across six continents, spanning 38°S to 60°N (2019–2022). Across the survey, 675 taxonomic entities were recorded (505 identified to species level), with rock pools containing 618 taxa (274 unique) and emergent rock 401 taxa (57 unique). Data show that microhabitat differences can strongly modify latitudinal biodiversity patterns, with pools generally supporting higher taxonomic and functional diversity than emergent rock, but with context-dependent outcomes under extreme conditions. By mediating exposure to environmental stress, intertidal microhabitats provide insight into how fine-scale variability interacts with latitudinal stress gradients to shape biodiversity distributions. Incorporating microhabitat variability into biogeographic frameworks is important for understanding global biodiversity patterns and predicting ecological responses to climate change.

  DOI

• A new tool for quantifying urbanization gradients across seascapes predicts habitat-forming macroalgal distribution patterns in the Salish Sea

  Marine Ecology Progress Series · 2025-12-04

  articleOpen access

  Nearshore environments on all continents are being transformed by rapid urbanization, which is projected to intensify in future decades. Landscape ecologists working in terrestrial and freshwater systems have developed several quantitative tools to help identify generalizable ecological patterns and responses to urbanization. These have yet to be fully utilized in the marine realm, though they require standardized measures of urbanization intensity that can be easily derived across cities and regions and at multiple spatial scales that reflect the varied nature of urban stressors and biotic response across functional groups. We developed an open-source resource in R that produces standardized measures of urbanization intensity based on a single spatial data layer of population density that is available at high resolution for all parts of the world. The tool was then employed to a case study evaluating urban-related gradients in the structural complexity of benthic macroalgal assemblages in the Salish Sea. Data from benthic photographic quadrat surveys at 22 sites distributed across ~90 km supported prior evidence from other regions that understory and canopy cover, kelp occurrence, kelp thallus density, and overall biogenic structural complexity decrease with increasing levels of land-based urbanization intensity. The standardized proxy of urbanization calculated for each site outperformed a suite of natural environmental variables, including temperature and water flow, in predicting abundances of kelp and other structurally complex macroalgae. These findings underscore the importance of urban stressors for habitat-forming macrophytes while providing a novel, open-source resource for performing urban-rural gradient analysis in urbanized seascapes.

  PublisherDOI

• Spatiotemporal variation in clam recruitment among beaches in Washington State (<scp>USA</scp>)

  Marine Ecology · 2024-01-04 · 3 citations

  articleOpen access

  Abstract Abundant clam populations provide ecosystem services and commercial and recreational shellfish harvests worldwide. Two non‐native clams (Manila clams, Ruditapes philippinarum ; eastern soft‐shell clams, Mya arenaria ) commonly populate mid‐intertidal zones of coarse‐sediment beaches in Washington State, USA. To better understand factors influencing their abundance, we used passive mid‐intertidal spat collectors to determine the density and distribution of clam recruits (150–500 μm shell length) at eight beaches spanning over 500 km and over two reproductive seasons (2016 and 2017). Cumulative seasonal recruitment (clams &lt;500 μm) in 2016 and 2017 at +1.0 m MLLW ranged from 800 to 125,000 m −2 for Ruditapes philippinarum and 50–85,000 m −2 for M. arenaria , and did not differ by substrate type at small scales (gravel vs. crushed shell). At larger scales, different interannual recruitment patterns across sites did not dramatically shift the ranked order of highest and lowest recruitment sites. Cumulative recruitment tended to be lower at warmer sites, while timing of peak recruitment was not consistently related to temperature. Sites also differed in the relative recruitment of the two clam species, but most beaches had greater densities of R. philippinarum than M. arenaria at both recruitment and juvenile stages. Although recruitment densities differed by two orders of magnitude across sites, post‐settlement factors eliminated initial spatial variation within a year, dampening recruitment variability among these beaches that all contribute to commercial and recreational clam production.

  PublisherOA PDFDOI

Frequent coauthors

• Christian E. Grue

  University of Washington

  24 shared

• Jason D. Toft

  Seattle University

  18 shared

• Hartwell H. Welsh

  Pacific Southwest Research Station

  18 shared

• Steven N. Murray

  17 shared

• Marc P. Hayes

  Washington Department of Fish and Wildlife

  16 shared

• Erin Muths

  16 shared

• David O. Duggins

  14 shared

• Richard F. Ambrose

  University of California, Los Angeles

  13 shared

Awards & honors

• Sound Indicators: A Review for the Puget Sound Partnership (…