Marine mammals are federally-protected species of interest, however their parasites are vastly unexamined. A lack of data regarding this host-parasite relationship hinders the understanding of ecosystem interactions, which poses consequences for successful conservation and management of marine mammals. To better understand the impacts of parasites on their marine mammal hosts, my research assessed the intestinal parasite burden of harbor seals (Phoca vitulina richardsi) in south Puget Sound. Harbor seal scats were collected under permit from the Commencement Bay floating dock haul-out site each month during and after the pupping timeframe. Non-invasive fecal floatation methods were used on scats to quantify the abundance and diversity of parasites from July 2017 to February 2018. An increase in prevalence of parasites within the population is expected following the weaning of seal pups as they begin feeding on invertebrates and fish implicated in parasite lifecycles. This research establishes baseline data on the intestinal parasite assemblage of Pacific harbor seals within Puget Sound, and the data will later be used in conjunction with molecular diet analysis to deduce the source of parasitic infection. My research can be used to assist with conservation efforts of harbor seals and can be broadly applied to other marine mammals within and outside of Puget Sound, serving as an example for future studies that consider the relationship between marine mammal hosts and their parasites.

Puget Sound is renowned for its biological productivity, but seasonal upwelling feeds this system with waters rich in dissolved CO₂ and consequentially accelerates the acidification of these ecosystems. In this region, aquaculture of bivalves has important economic and cultural roles that are threatened by ongoing changes in climate and water chemistry. For mussels and oysters, shell strength and integrity are the first defense in combating biotic and abiotic stressors but exposure to low pH can drastically weaken calcium carbonate shells. This study examined the effects of variable pH on the shell strength of the Mediterranean mussel, Mytilus galloprovincialis, and the Olympia oyster, Ostrea lurida. M. galloprovincialis and O. lurida were attached to ORCA buoys at three sites in Puget Sound, at either 5m or 20m depth on the buoy tether for three months. This spatial diversity exposed the bivalves to naturally occurring variations in pH which were continuously measured in situ by the ORCA buoys. The resulting shell strength was measured using an Instron Universal Testing Machine by puncturing a small hole in each shell. These results were evaluated using a two-way ANOVA between sites and depths. We expected that both species will have much weaker shells at deeper depths where pH is generally lower. This study can provide physiological thresholds of economically and ecologically important species under current and future oceanographic conditions.

Manila clams, Ruditapes philippinarum, are a widely used species in Washington shellfish aquaculture. Juveniles in particular have high mortality rates due in part to predation, but the extent of this predation is unknown. This study investigates the prey size range and preference shown by the crabs Hemigrapsus nudus, Metacarcinus gracilis, Cancer productus, and Romaleon antennarium when preying on R. philippinarum. To test if crabs prefer to prey on larger clams due to their higher food content, we placed crabs and clams together in microcosms and measured mortality rates of the clams. It was found that all crabs could eat all tested clam sizes. Cancrid crabs preferred to eat larger clams; R. antennarium ate the most clams. In contrast, H. nudus had no preference for a particular clam size. Based on these results, countermeasures against juvenile Manila predation should have a special focus on cancrid crabs, and further research on the reasons behind the trend of cancrid preference for larger juveniles should be considered. 

Within the complex San Juan Channel (SJC) ecosystem, marine birds play a fundamental and dynamic role. Due to their interactions with several trophic levels and climatic factors, seabirds are important indicators of environmental health. Their necessity to be monitored is further compounded by the fact that the SJC has recently experienced abnormal sea surface temperatures and conditions due to the Marine Heat Wave in 2013 – 2016. Thus, our goal was to monitor how the marine bird communities have been impacted by these climatic changes. We first characterized the Fall of 2017 by collecting survey data on community composition and temporal and spatial densities. Then, we contextualized 2017 within the past 10 years of survey data. In order to highlight the specific species that have large influences on the overall bird density, we focused on 5 main species: the Glaucous-winged Gull, Brandt's + Pelagic Cormorant, Common Murre, Surf + White winged Scoter, and Pacific Loon. We found that 2017 had the lowest total bird density in the past decade, as well as a complex mixture of temporal and spatial trends from previous study years. Additionally, we were able to highlight the significant connections between marine birds and three climatic indices - North Pacific Gyre Oscillation (NPGO), Oceanic Niño Index (ONI), and Sea Surface Temperature (SST). Our findings indicate that these communities are impacted by both local and global water and air conditions. However, many of the migratory birds, such as Common Murres, are perhaps impacted greater by changes in their remote habitats, such as their breeding grounds and migratory routes. Additionally, Common Murres proved to be a main driving species behind annual density trends, even frequently masking other more minute density trends in less abundant birds. Further research is needed to understand the relationships between species-specific densities and other climatic patterns.

A seed’s successful transition to a seedling depends on the suitability of the surrounding environment. All plants need water, sunlight, favorable temperatures, and soil nutrients to survive. On top of these essentials, interactions with other organisms through competition, herbivory, or disease may also have an impact. The goal of this study is to assess which factors influence tree germination in Washington’s temperate forests. Are there essentials without which seeds fail to complete the pivotal transition between embryo and tree? This question was explored using data collected since 2014 in a 25.6 hectare plot located in the Gifford Pinchot National Forest (WA). The dominant trees here, including Western hemlock and Douglas fir, were the focus species of this study. Forty seed traps distributed throughout the plot collected falling tree seeds so that they could later be identified to species and counted in the lab. Germinants and seedlings were recorded within a square meter adjacent to each seed trap, along with environmental factors such as soil moisture and sun exposure. Regression analyses were used to assess whether germination rates (the proportion of seeds that successfully germinated) were influenced by environmental factors, other organisms, seed densities, or year. While analyses and data collection are ongoing, results thus far indicate a negligible role for soil moisture and sunlight in germination. On the other hand, the presence of other vegetation decreased germination, while the presence of nurse logs increased it. Germination is an important and delicate life stage for every tree, and through their influence on it environmental factors may shape the species composition of these communities. Identifying relevant factors may also provide some ability to anticipate how these trees will respond to the warmer and drier conditions expected to define climate change in the Pacific Northwest.

Non-vascular epiphytes have been determined to grow in a non-random distribution in the canopies of Acer macrophyllum in the Hoh Rainforest, Washington. Nitrogen (N) source has been suggested as a potention driver of the distribution, and stable isotopic analyses were used to consider the influence of this factor. Three epiphyte species, the lycophyte Selaginella oregana, and bryophytes Rhytidiadelphus loreus, and Neckera douglasii, and four trunk dwelling species, Selaginella oregana, and the bryophytes Hypnum subimponens, Leucolepis acanthoneuron, and Metaneckera menziesii, were selected for analyses on the basis of their distribution on five host trees. Samples of plant tissues, as well as canopy and trunk soil were analyzed using isotope ratio mass spectrometry to identify the N source of each species. N source varied significantly by species and growing location. δ¹⁵N values of all bryophyte species confirmed an atmospheric N source. Results for the lycophyte S. oregana varied significantly in response to its relationship with R. loreus, which grows above it in mats in the inner canopy. Selaginella oregana appears to use canopy soil N in the presence of R. loreus, and atmospheric N in its absence on the trunk. These findings suggest the role of niche partitioning in the coexistence of S. oregana and R. loreus within the canopy, and illustrate the likely ability of S. oregana to vary its N source based on competition for the resource. No study of this kind has been conducted in the Hoh Rainforest to date, and this work highlights the intersection of abiotic and biotic factors in determining epiphyte species distributional patterns in the temperate forest ecosystem. 

The exceptional biodiversity in the Coral Triangle is partially attributed to the elevated rates of evolution that occur in the shallow reefs of the Indo-Pacific Ocean. Its current geographical location and complex oceanographic history have facilitated rapid speciation in many lineages of coral reef fishes. The processes causing these unique evolutionary patterns can be closely studied in Eviota (Gobiidae), a widespread lineage of rapidly diverging marine fishes. Their restricted dispersal capabilities, short generation time, and specific habitat preferences have facilitated repeated exploitation of novel niches and thus catalyzed their high species diversity. Here, we examine morphological and genetic diversity in relation to biogeography in the Blackbelly Dwarfgoby, the Eviota atriventris species complex. This study analyses E. atriventris from nine localities across its range spanning the Indo-Australian Archipelago to determine whether recent speciation has occurred at fine scales across the Coral Triangle. Our combined morphological and molecular phylogenetic analysis examines differences in meristic, coloration, morphometrics, and gene sequence data from seven mitochondrial and nuclear genes. Results show strong divergence in mitochondrial DNA sequences in Milne Bay, Papua New Guinea and Solomon Islands (eastern) populations, as compared with a western haplotype from Indonesia. This suggests that lineages within E. atriventris are geographically and genetically isolated. However, evidence from nuclear gene sequences show few differences between groups, and morphological data to support the separation of these populations are inconclusive. These similarities imply that eastern and western haplotypes may be in the early stages of speciation. Due to phylogenetic evidence and lack of geographic overlap, these lineages may be considered separate species under some species concepts. This study illustrates challenges in separating and defining species concepts for closely related species with conserved morphology.

Anthropogenic habitat modification is one of the most widespread and immediate threats to terrestrial biodiversity. One of the effects of this threat is the alteration of local microclimates, to which ectotherms are particularly sensitive. The shifts in spatial distributions seen following conversion, where some species decline while others persist in these modified habitats, may be in part explained by a change in the thermal conditions. However, understanding how thermal biology may affect species responses to habitat conversion has been addressed by relatively few studies. Here we examined how the change in the thermal conditions may affect the response of the poison frog, Oophaga pumilio to habitat modification by measuring three aspects of its thermal niche: field body temperatures, preferred body temperatures, and upper thermal maxima. We measured body temperatures in the field and behaviorally selected temperatures in the laboratory to determine if individuals in warm, pasture habitats have higher field temperatures and select for higher body temperatures than individuals found in cooler forests. Additionally, we measured upper thermal maxima to determine if individuals from altered habitats exhibit higher tolerances than those in forest remnants. Our results showed that individuals found in altered habitats have higher body temperatures than those in forest and also preferred higher body temperatures on average than those from forest. However, while there was considerable variation among individuals in thermal maxima, we found no significant difference of thermal maxima between individuals from the two distinct habitats. These results suggest that this species may be able to experience acclimation and/or selection on preferred body temperatures as individuals are exposed to novel temperature regimes in altered habitats but may not be able to cope with increasing temperatures if high daytime temperatures frequently approach their upper thermal tolerances.