Life Sciences Commons^™

Seasonal Comparison Of Environmental Dna And Traditional Sampling Techniques For Detecting Coastal Tailed Frogs (Ascaphus Truei) In Northern California, Lauren Smith

Cal Poly Humboldt theses and projects

While environmental DNA (eDNA) sampling has been shown to provide higher detection rates for aquatic amphibians compared to traditional sampling, the effect of season and stream characteristics on the efficacy of eDNA sampling remains unclear. The pH, turbidity, water temperature, and flow rate of streams may affect eDNA concentrations, and consequently influence detection rate. The purpose of this research was to (1) compare the detection rates of eDNA and traditional sampling techniques during different seasons, (2) observe the effects of stream characteristics on eDNA concentrations, and (3) review the relationship between animal abundance and eDNA concentrations at specific sampling sites. …

Baseline Characterization Of Nearshore Rocky Reef Fishes Found In Northern California Marine Protected Areas, Jay M. Staton

Cal Poly Humboldt theses and projects

The nearshore rocky reef habitat along California’s North Coast supports a diverse assemblage of ecologically, economically, and culturally important fishes. In December 2012, a network of Marine Protected Areas (MPAs) was established in Northern California with the goal of protecting these species. Our study utilized collaborative hook and line fishing methods, while employing local charter fishing vessels, to establish a baseline of rocky reef fishes associated with four MPAs and four unprotected reference sites. These baseline data were then used to inform generalized additive models (GAMs) to explore potential drivers of relative abundance, size, and diversity of fishes. Understanding what …

Habitat Use And Movement Patterns Of Two Redwood Forest Salamanders, Aneides Vagrans And Ensatina Eschscholtzii, With An Examination Of The Efficacy Of Pit Tags For Marking Small Plethodontids, Christian Brown

Cal Poly Humboldt theses and projects

The habitat use and movements of small, secretive salamanders are generally poorly understood, in part due to the difficulty associated with marking and recapturing such animals. This study was designed to test the efficacy, both in the laboratory and in the field, of using passive integrated transponder (PIT) tags to mark and track two small-bodied plethodontid salamander species native to coastal northwestern California, Aneides vagrans, the Wandering Salamander, and Ensatina eschscholtzii, the Ensatina Salamander.

Aneides vagrans inhabits tree crowns. Using cover objects and visual encounter surveys, I searched for A. vagrans in the angiosperm understory canopy at least twice …

Modeling The Spread Of Sudden Oak Death Across A Heterogeneous Landscape In Redwood National Park Using A Spatially-Explicit Epidemiological Model, Laura A. Morgan

Cal Poly Humboldt theses and projects

The pathogen Phytophthora ramorum, the causal agent of Sudden Oak Death (SOD), is responsible for the deaths of millions of oak (Quercus spp.) and tanoak (Notholithocarpus densiflorus) trees in California and Oregon (USA). A recent infection in Redwood National Park (RNP) in California (USA) provided an opportunity to adapt an existing SOD model to assess the efficacy of current and proposed management strategies. A common method of SOD treatment includes killing both infected and uninfected hosts in the area of infection, as well as the area surrounding the infection to create buffers to account for undetected …

In The Face Of Drought: Do Fuel Treatments Promote Resistance To Multi-Year Drought In A Mixed-Conifer Forest Of Northern California?, Michael Vernon

Cal Poly Humboldt theses and projects

Climate change is predicted to increase the frequency, duration, and severity of drought events across many bioregions. Forest managers have two active management techniques to promote resistance and resilience to drought: prescribed fire and mechanical thinning. Generally applied to reduce fuels and fire hazard, treated areas may also reduce competition for resources that may improve tree-growth during drought and reduce mortality. The recent severe and prolonged drought in California allowed me to investigate the effects of climate stress and fuel treatments on tree growth responses in a dry mixed-conifer forest ecosystem.

To assess tree-growth responses to fuel treatments during severe …

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, …