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Full-Text Articles in Life Sciences

Using Environmental Dna And Occupancy Modeling To Estimate Rangewide Metapopulation Dynamics Of The Endangered Tidewater Goby Eucyclogobius Spp., Chad M. Martel Jan 2019

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

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 ...


Tree Squirrels And Fishers In Northern California: The Effects Of Masting Hardwoods On Stand Use, Andria M. Townsend Jan 2019

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

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 mast production capacity of that stand, and 2) fisher stand ...


Freshwater And Marine Survival Of Coho Salmon (Oncorhynchus Kisutch) As A Function Of Juvenile Life History, Grace Katherine Ghrist Jan 2019

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

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 estimates are ...


Effects Of Longline Oyster Aquaculture On Benthic Invertebrate Communities In Humboldt Bay, California, Hannah C. Coe Jan 2019

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

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 ...


Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler Jan 2019

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and ...


Response Of Headwater Amphibians To Long-Term Logging Impacts And Assessing Potential For Restoration In Redwood National And State Parks, Alyssa Marquez Jan 2019

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

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 as ...


Distribution Of Sea Star Wasting Disease Symptoms In Pisaster Ochraceus In The Rocky Intertidal Zone, Jana N. Litt Jan 2019

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

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 ...