Ecology and Evolutionary Biology Commons^™

Estimating Space Sharing Between Seabird, Pinniped, And Human Use In The Northern California Coast, Claire Marie Nasr

Cal Poly Humboldt theses and projects

Rocky coastlines incur high impacts from human use, but these places are also essential habitat for marine wildlife including seabirds and pinnipeds (seals and sea lions). Marine wildlife use coastal rocks to breed, rest, and engage in social interaction and exhibit different habitat use during the breeding and non-breeding season. Peak timing of human use occurs in spring summer, coinciding with breeding seasons for colonial seabirds and gregarious pinnipeds. The high potential of spatial and temporal overlap between human and seabird use of rocky coastlines could lead to high risk of disturbance events. I investigated the relative risk of disturbance …

Drought And Coyotes Mediate The Relationship Between Mesopredators And Human Disturbance In California, Molly K. Parren

Cal Poly Humboldt theses and projects

Mesopredators in California are facing two major changes to their ecosystem: drought and the expansion of human disturbance. As a result, mesopredators are likely shifting their habitat use as well as their interspecies interactions to balance resource needs and risk-taking on the landscape. In response to severe drought, the California Department of Fish and Wildlife deployed 585 camera traps throughout the Mojave Desert and Central Valley documenting mammalian mesopredator presence in a drought year (2016) and a post-drought year (2017). The objectives of this study were to examine spatial patterns of mesopredator occurrence and co-occurrence with a dominant predator, the …

Autumn Roost Selection By Male Hoary Bats (Lasiurus Cinereus) In Northern California, Danielle (Skye) Salganek

Cal Poly Humboldt theses and projects

The hoary bat, Lasiurus cinereus, is a solitary bat that roosts in the foliage of trees throughout the western hemisphere. Roosts are subject to the ambient temperature of their surroundings, thus hoary bats undergo long-distance migrations between summer and winter ranges to avoid freezing temperatures. Habitat selection has been studied during the summer for maternal female hoary bats, but not during migration and winter. Autumn migration coincides with the hoary bat mating period and it has been proposed that male and female bats may rendezvous on migration paths. Individuals may select roosts in stopover locations that enhance fitness by providing …

Relationship Between Habitat And Barn Owl Prey Delivery Rate And Composition In A Napa Valley Vineyard Agroecosystem, Dane A. R. St. George

Cal Poly Humboldt theses and projects

The provision of habitat for natural enemies of agricultural pests is common in integrated pest management approaches globally but has rarely been examined for vertebrate predators controlling vertebrate pests. To mitigate the economic and environmental costs of treating for rodent pests, winegrape producers in Napa Valley, California, have installed nest boxes to attract barn owls (Tyto alba) to their properties, but their effectiveness to control rodent pests in vineyards has not been thoroughly tested. A rigorous estimate of the number of rodents barn owls remove from the landscape is a necessary first step, and this study aimed to …

Using Environmental Dna And Occupancy Modeling To Estimate Rangewide Metapopulation Dynamics Of The Endangered Tidewater Goby Eucyclogobius Spp., Chad M. Martel

Cal Poly Humboldt theses and projects

Conservation of species is most effective when metapopulation dynamics are well understood and incorporated into management plans, allowing managers to target conservation efforts where they will be most effective. The development of environmental DNA (eDNA) methods provides an efficient and highly sensitive approach to generate presence and absence data needed to elucidate metapopulation dynamics. Combining sample detection histories from eDNA surveys with occupancy models that account for non-detection can offer unbiased estimates of rangewide metapopulation dynamics. However, traditional occupancy models do not allow direct evaluation of the drivers of site occupancy, extinction, and colonization. Herein, I utilize a novel dynamic …

Host-Plant Specialization And Nesting Biology Of Anthidium Placitum (Megachilidae) In Northwest California, Christopher Pow

Cal Poly Humboldt theses and projects

Premise of the study: Although the study of bees and their pollination services has grown immensely in recent years, the natural history of most solitary bee species is still largely unknown. The goal of this study was to contribute to the natural history dossier of a late-season wool carder bee, Anthidium placitum Cresson (Megachilidae), by establishing which plants it uses as sources of nectar and pollen as well as documenting details of its flower-handling behavior, mating behavior, and nesting biology in northwestern California.

• Methods: Field observations were made at five sites in Del Norte, Humboldt, Siskiyou, and Trinity counties. …

Tree Squirrels And Fishers In Northern California: The Effects Of Masting Hardwoods On Stand Use, Andria M. Townsend

Cal Poly Humboldt theses and projects

In western North America, tree squirrels such as western gray (Sciurus griseus) and Douglas squirrels (Tamiasciurus douglasii) are potentially important prey for fishers (Pekania pennanti). Western gray squirrels in particular may be highly ranked due to their large body size. Masting trees including black oak (Quercus kelloggii) and tanoak (Notholithocarpus densiflorus) produce an important food source for tree squirrels; therefore, forest stands containing these trees may be useful to foraging fishers. I hypothesized that; 1) the abundance of western gray and Douglas squirrels in a stand is influenced by the …

Contribution Of Juvenile Estuarine Residency In A Bar-Built Estuary To Recruitment Of Chinook Salmon (Oncorhynchus Tshawytscha), Emily Katherine Chen

Cal Poly Humboldt theses and projects

Estuaries are commonly touted as nurseries for out-migrating salmonids, providing higher prey availability than streams, a physiological transition zone, and refugee from marine predators. Yet the diversity of estuaries makes it difficult to generalize the effect they have on salmonid recruitment. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low flow, closing access to the ocean and disrupting outmigration. In this thesis, I evaluated how residency in a bar-built estuary affects the growth, survival, and ultimately recruitment of Chinook salmon (Oncorhynchus tshawytscha) in Redwood Creek, California. I conducted a mark-recapture experiment on out-migrating …

Ectomycorrhizal Fungal Community Assembly On Seedlings Of A Neotropical Monodominant Tree, Carolyn Delevich

Cal Poly Humboldt theses and projects

Formation of ectomycorrhizae may facilitate early seedling survival of ectomycorrhizal tree species due to enhanced nutrient acquisition. This could be especially important in heavily shaded understories of tropical monodominant forests where host plant photosynthetic capacity is limited. Little information is available on ectomycorrhizal (ECM) fungal colonization or community development of monodominant seedling cohorts, which have high survival rates. Following a 2016 mast seeding event, we sequentially measured percent colonization and species composition of ECM fungi on live and recently dead seedlings of the tropical monodominant tree Dicymbe corymbosa. We also compared seedling ECM fungi to those of nearby adult …

Distribution Of Sea Star Wasting Disease Symptoms In Pisaster Ochraceus In The Rocky Intertidal Zone, Jana N. Litt

Cal Poly Humboldt theses and projects

Beginning in 2013, many species of sea stars (phylum Echinodermata) along the Pacific coast experienced severe mortality due to sea star wasting disease (SSWD). The ochre sea star, Pisaster ochraceus, experienced one of the highest mortality rates during this outbreak. To test the hypothesis that the intertidal distribution of ochre sea stars influences the incidence and progression of SSWD symptoms, I documented the occurrence of symptoms and survivorship in adult and juvenile stars in the upper and lower portions of the mid-intertidal zone. I also chronicled the progression of SSWD symptoms among individually tagged adult stars to assess changes in …

Response Of Headwater Amphibians To Long-Term Logging Impacts And Assessing Potential For Restoration In Redwood National And State Parks, Alyssa Marquez

Cal Poly Humboldt theses and projects

The timescale of community response to disturbance varies drastically, and slow-recovering ecosystems such as coastal redwood forests may take hundreds of years to return to old-growth conditions post-logging. Few studies have quantified long-term (>50 years) impacts of disturbance on ecosystems, specifically aquatic ecosystems. This study provides evidence of the persistence of historical logging impacts 50 years post-logging through the comparison of headwater amphibian populations (occupancy and abundance) and stream characteristics using a control-treatment study with a logged watershed, Streelow Creek, as the treatment and a pristine old-growth watershed, Godwood Creek, as the control. The immediately adjacent old-growth watershed acts …

Life History Of The Coastal Tailed Frog (Ascaphus Truei) Across An Elevational Gradient, Adrian Daniel Macedo

Cal Poly Humboldt theses and projects

The life history of a species is described in terms of its growth, longevity, and reproduction. Unsurprisingly, life history traits are known to vary in many taxa across environmental gradients. In the case of amphibians, species at high elevations and latitudes tend to have shorter breeding seasons, shorter activity periods, longer larval periods, reach sexual maturity at older ages, and produce fewer and larger clutches per year.

The Coastal Tailed Frog (Ascaphus truei) is an ideal species for the study of geographic variation in life history because it ranges across most of the Pacific Northwest from northern California …

Effects Of Longline Oyster Aquaculture On Benthic Invertebrate Communities In Humboldt Bay, California, Hannah C. Coe

Cal Poly Humboldt theses and projects

Oyster aquaculture has had a commercial presence in Humboldt Bay for nearly 60 years and has experienced changes in scope and methodology as the industry has grown. The traditional method of bottom-culture oyster beds has been phased out, with longline oyster aquaculture becoming the common replacement. However, this transition has preceded much of the research regarding potential impacts to the broader ecosystem. The benthic invertebrate community of Humboldt Bay is a vital food source for many commercially important fishes, as well as for the many shorebirds that utilize Humboldt Bay. The importance of the invertebrate community to the ecosystem highlights …

Freshwater And Marine Survival Of Coho Salmon (Oncorhynchus Kisutch) As A Function Of Juvenile Life History, Grace Katherine Ghrist

Cal Poly Humboldt theses and projects

Juvenile Coho Salmon (Oncorhynchus kisutch) in coastal California streams exhibit various life history strategies during their freshwater development. One strategy of interest to managers and conservationists is the early migrant. Juvenile early migrants emigrate from natal habitat into lower parts of the watershed or estuary during their first fall or winter, where they rear before migration to the ocean. By contrast, the more prevalent spring migrant resides in natal reaches over the winter and migrates directly to the ocean the following spring. Salmon monitoring programs generally estimate juvenile production and demographic rates using only spring migrants, and these …

Evaluation Of Range-Wide Occupancy And Survey Methods For The Giant Kangaroo Rat (Dipodomys Ingens), Alyssa E. Semerdjian

Cal Poly Humboldt theses and projects

Though habitat suitability and occupancy are often correlated, they cannot always be inferred from each other. Therefore, a solid understanding of both is essential to effectively manage species. Recent studies have assessed range-wide habitat suitability for the giant kangaroo rat (Dipodomys ingens; GKR), but data regarding occupancy is lacking in parts of its distribution. Satellite and aerial imagery were used to identify GKR burrows across their known range, producing a range-wide occupancy map and non-invasive survey methods including track plates, manned flight, unmanned aerial vehicle, and sign surveys were conducted to determine effective methods for monitoring GKR occupancy. …

The Influence Of Microclimate And Local Adaptation For A Climate-Sensitive Species (Aplodontia Rufa), Jennie K. Jones Scherbinski

Cal Poly Humboldt theses and projects

Climate change models and analyses predict a disproportionate impact on climatically sensitive species such as the mountain beaver (Aplodontia rufa). Mountain beavers have physiological constraints that limit their distribution to cool, moist climates. While mountain beavers have persisted through past periods of climate change, increasing temperature since the last glacial maximum is believed to have had a strong influence in reducing their range. This is particularly true for the Point Arena subspecies (A. r. nigra, “PAMB”), found towards the southwestern edge of their range on the coast of California. Here, I examined the climatic niche of …

Export Of Invertebrate Drift From Fishless Headwater Streams, Jonathan M. Hollis

Cal Poly Humboldt theses and projects

An understanding of ecological linkages between headwater systems and downstream habitats is needed to enhance management practices for aquatic conservation. I quantified and described the export of invertebrate drift from fishless headwater streams to assess its potential importance to downstream populations of coastal cutthroat trout (Oncorhynchus clarki clarki) in the lower Klamath River in northern California. From June 2015 through April 2016, I sampled invertebrate drift in six fishless headwaters in the sub-basins of Tectah, Ah Pah, and Tarup creeks. Concurrently, I collected invertebrate drift and trout diet samples from adjoining fish-bearing streams. Drift export rates were lowest …

Evaluating Current And Future Range Limits Of An Endangered, Keystone Rodent (Dipodomys Ingens), Ivy V. Widick

Cal Poly Humboldt theses and projects

Climate is often considered the single most important factor limiting species’ ranges. Other factors, such as biotic interactions, are often assumed to be included via abiotic proxies. However, differential responses to climate change may decouple these relationships or lead to adaptation to novel environments. Accounting for competition and local adaptation should more accurately describe environmental factors influencing current distributions and increase the predictive accuracy of future distributions. Modeling the endangered giant kangaroo rat (Dipodomys ingens) is an excellent application of these model improvements, as the species range consists of geographically and genetically isolated populations experiencing disparate climatic change. …

The Effects Of Forest Degradation On Dna Methylation In Central African Songbirds, Andrew K. Wiegardt

Cal Poly Humboldt theses and projects

Environmentally-induced stress can initiate a molecular response through DNA methylation, which can alter gene expression, thereby serving as a mechanism allowing individuals to acclimate to a changing environment within their lifetime. In addition to DNA methylation, the production and release of corticosterone is a physiological mechanism by which birds can cope with acute environmental stressors. To assess how environmental stress impacted DNA methylation and corticosterone, I collected blood and feather samples from three understory avian species (Alethe castanea, Bleda notatus and Pseudalethe poliocephala), along a disturbance gradient in the lowland Guinean rainforest adjacent to the village of …

Effects Of Manual And Mechanical Ammophila Arenaria Removal Techniques On Coastal Dune Plant Communities And Dune Morphology, Monique R. Silva Crossman

Cal Poly Humboldt theses and projects

The removal of invasive species as part of the restoration process can allow natives organisms to rebound. An ecosystem that incurs damages from invasive species is coastal sand dunes, which are dynamic systems. Some coastal sand dunes on the west coast of the United States have been invaded by Ammophila arenaria. The invasive grass, A. arenaria, is thought to alter and stabilize foredune morphology and reduce populations of native species. The objectives of my research are to examine the effects that manual and mechanical A. arenaria removal techniques have on coastal sand dune morphology and vegetative cover over time. …

Jeweled Spider Flies (Eulonchus Tristis) Are Important Pollinators Of Iris Bracteata, A Rare Siskiyou Mountain Endemic, Jean-Paul E. Ponte

Cal Poly Humboldt theses and projects

Little is known about the pollination biology of the Pacific Coast Irises (Iris: series Californicae, hereafter PCI), especially who visits and pollinates their flowers. In general, Iris flowers are considered bee-pollinated, however, flies in the genus Eulonchus (Acroceridae) are known to visit some PCI members. Therefore, I assessed the relative importance of Eulonchus and other insect visitors to the pollination of a rare PCI species native to the Siskiyou Mountains, I. bracteata.

Methods. I quantified pollinator importance for all flower visitors at sites in northern California and southern Oregon as the product of average visit rate and …

Hunting Habitat Use And Selection Patterns Of Barn Owl (Tyto Alba) In The Urban-Agricultural Setting Of A Prominent Wine Grape Growing Region Of California, Xeronimo A. Castaneda

Cal Poly Humboldt theses and projects

Large scale conversion of uncultivated land to agriculture threatens wildlife and can diminish ecosystem services provided by nature. Understanding how wildlife provision ecosystem services may incentivize wildlife conservation in agricultural landscapes. Attracting barn owls (Tyto alba) to nest on farms for pest management has been documented worldwide, but has not been thoroughly evaluated in vineyard agroecosystems. Napa Valley, California is a renowned winegrape growing region, and viticulturists encourage barn owl occupancy to help minimize plant damage from pocket gophers (Thomomys bottae) and voles (Microtus spp.). This study aimed to establish a basis for revealing the …

Persistence Of Stream Restoration With Large Wood, Redwood National And State Parks, California, Diedra L. Rodriguez

Cal Poly Humboldt theses and projects

The conservation and recovery of anadromous salmonids (Oncorhynchus sp.) depend on stream restoration and protection of freshwater habitats. In-stream large wood dictates channel morphology, increases retention of terrestrial inputs such as organic matter, nutrients and sediment, and enhances the quality of fish habitat. Historic land use/land cover changes have resulted in aquatic systems devoid of large wood. Restoration by placement of large wood jams is intended to restore physical and biological processes. An important question for scientists and restoration managers, in addition to the initial effectiveness of restoration, is the persistence and fate of large wood installations. In this …

Apparent Survival Of Snowy Plovers Varies Seasonally, Nora C. Papian

Cal Poly Humboldt theses and projects

Survival is an important vital rate that contributes to population viability, but is infrequently monitored and studied, especially compared to productivity. Furthermore, factors that limit survival and the relative effect on survival are often unknown. I used mark-resight observations of a small (~350) population of threatened Snowy Plovers (Charadrius nivosus nivosus) to quantify seasonal and annual variation in survival and movement between three coastal locations across ~70 km in Humboldt County, California. The return of individuals to non-breeding flocks at three locations was high between years (75-81%). Movement between three locations varied greatly, although most (n = 137) …

Seasonal Home Range Variation And Spatial Ecology Of Peregrine Falcons (Falco Peregrinus) In Coastal Humboldt County, Ca, Elizabeth-Noelle F. Morata

Cal Poly Humboldt theses and projects

Peregrine falcons (Falco peregrinus) are renowned for their migratory habits, with ‘peregrinus’ often translated as ‘wanderer’ or ‘pilgrim’. However, their migratory habits may differ by population and some peregrine may falcons forgo migration when climate and resources remain stable. To examine peregrine falcon home range and space use, I fitted GPS-satellite transmitters to nine breeding adults in coastal northern California, an area with a mild climate and abundant waterbird populations. I used kernel density estimates and time-local convex hulls to examine seasonal home ranges and within-home range habitat use. All nine peregrine falcons remained resident in …

A Comparison Of Community Structure In Regulated And Unregulated Reaches In The Upper Eel River, California, Lara Stephanie Jansen

Cal Poly Humboldt theses and projects

Flow regulation of rivers by impoundments and diversions can reduce hydrological variability. As a result, densities of algae and benthic macroinvertebrates often increase, but many sensitive taxa are lost, causing shifts across the food web. In Northern California, dams that reduce winter peak floods can result in the primary consumer community becoming dominated by grazers that are relatively invulnerable to predation, which can reduce the amount of energy transferred up the trophic levels. The steeper slope of the spring hydrograph recession limb downstream of a dam can also greatly impact instream diversity of periphyton, invertebrates and fish. The dam and …

Evaluating Habitat Selection Models To Improve Site Selection In A Population Monitoring Program For Townsend's Big-Eared Bats (Corynorhinus Townsendii), Katrina J. Smith

Cal Poly Humboldt theses and projects

Winter roost (hibernacula) surveys offer a unique opportunity to monitor Townsend’s big-eared bats (Corynorhinus townsendii) while the population is generally closed, using a simple count method to census the population. Existing knowledge of C. townsendii hibernacula facilitates long-term population trend analysis but improving the accuracy of trend estimates requires identification of additional hibernacula to increase the proportion of the population monitored. Over 800 caves are known within Lava Beds National Monument; 322 of these have never been surveyed in the winter and could potentially hold a substantial portion of the C. townsendii population currently missing from the annual …

What Should Go In A Wildlife Professional’S Geospatial Toolbox? (Response Data), William Bean, Ryan C. Baumbusch, Brooke Berger, Matthew Delheimer, Lee J. Hecker, Matthew Lau, Megan C. Milligan

Research Data Sets

Geospatial tools have become a critical component to most wildlife studies and management questions. With a diversity of approaches available, current and future wildlife professionals deserve guidance on the most important tools to answer these questions. Younger professionals may be expected to know a separate set of skills from those required further on in their career. We conducted an online survey and a year-long search of job advertisements to identify the most important geospatial approaches, techniques, programs, and ancillary skills for wildlife professionals. We provide the results of these 2 efforts so that wildlife professionals interested in geospatial tools can …

A Comparison Of Benthic Macroinvertebrate Assemblages Between Perennial And Intermittent Headwater Streams Of The Mattole River In Northern California, Usa, Mason S. London

Cal Poly Humboldt theses and projects

Intermittent streams are common throughout the world and comprise 60% or more of total river lengths in the conterminous United States. Despite their prevalence, intermittent streams are understudied, particularly first-order headwater streams, which are vital for maintaining the function, health and biotic diversity of river networks. In June 2016, I sampled five intermittent and five perennial headwater streams in the Mattole River watershed in northwestern coastal California, USA, to compare benthic macroinvertebrate (BMI) assemblages between intermittent and perennial streams. BMI samples were collected using a 500µm mesh D-net at eight randomly located riffles along a 150-m reach, and then composited, …

The Influence Of Canopy Cover And Climate On Early Life-Stage Vital Rates For Northern Red-Legged Frogs (Rana Aurora), And The Implications For Population Growth Rates, Kecly Mcharry

Cal Poly Humboldt theses and projects

Many amphibian species are in decline due to habitat loss and changing climates. Understanding how habitat characteristics and climate influence vital rates, and if they act in concert or in opposition can inform management decisions. This study investigated the potential interaction of canopy cover and climate on early stage vital rates of northern red-legged frogs. Demographic data were collected from sample populations in experimental canopy cover treatments across a latitudinal distribution. Rearing cages were used to estimate hatch success, and mark-recapture surveys to estimate tadpole survival. Ambient air temperature was used as an index of climate because it is easily …