Life Sciences Commons^™

Growth And Survival Of Amphibians Exposed To Road Salt And Glyphosate-Based Herbicide, Jerica Eaton

Mahurin Honors College Capstone Experience/Thesis Projects

Amphibian populations are threatened by increasing levels of environmental pollution resulting from human activities. Areas with mixed land use that include agriculture and urban development experience increased contamination from surface herbicide and road deicer application. Upon entering water sources, these chemicals have the capacity to disrupt the natural dynamics of aquatic ecosystems. This study aimed to evaluate the effects of these contaminants on amphibian populations. I used the spotted salamander (Ambystoma maculatum) as a model, rearing larvae from hatching to metamorphosis. I subjected larvae in each of the treatment groups to varying levels of herbicide and salt concentrations. …

Analysis Of Population Structure In A California Newt (Taricha Torosa) Metapopulation, Jessica Vincent

Mahurin Honors College Capstone Experience/Thesis Projects

As anthropogenic influences take an ever-increasing toll on the environment, understanding how environmental change affects species is paramount. Concern regarding decline in amphibian populations has spurred research examining the effects of habitat change on the dynamics of populations at landscape levels. One important goal is to understand how gene flow among populations is affected by changes in habitat. Biologists need to consider the relationship between gene flow and habitat alterations so that movements among individual breeding ponds can be maintained over time, reducing risk of local extinction events. This study focuses on patterns of gene flow among thirteen populations of …

Non-Adaptive Phentypic Plasticity: Morphology, But Not Swim Speed, Of Spotted Salamander Larvae Is Affected By "Terrestrial" And "Aquatic" Herbicides, Mitchell Schooler

Mahurin Honors College Capstone Experience/Thesis Projects

1. Phenotypic plasticity, although ubiquitous, may not always be advantageous. In cases where individuals expressing an induced phenotype outperform non-induced individuals, the phenotypic plasticity is considered adaptive. Conversely, if the individuals with an induced phenotype underperform relative to non-induced individuals, then the plasticity is maladaptive. A final possibility is that both induced and non-induced individuals perform equally well (or poorly). This would be a case of non-adaptive (i.e. neutral) phenotypic plasticity.
2. We investigated the mode of phenotypic plasticity induced by four glyphosate-based herbicides in larvae of the spotted salamander, Ambystoma maculatum (Shaw, 1802), by determining whether the herbicides induced different morphologies, …

Landscape Genetics Of The Endangered California Tiger Salamander (Ambystoma Californiense) In The Los Vaqueros Watershed, Ryan Neal Vincent

Mahurin Honors College Capstone Experience/Thesis Projects

Genetic diversity is essential for maintaining healthy biological systems, and dispersal-mediated gene flow increases genetic diversity by introducing new alleles to a gene pool. Populations that frequently experience gene flow will show characteristic similarities in allele frequencies. Measuring genetic diversity among many populations across a landscape has proven to be a powerful approach for assessing the ways that habitat discontinuities may affect patterns of gene flow, and in turn, influence allele frequencies and population dynamics. This study examines the landscape-level population genetic structure of the California tiger salamander, Ambystoma californiense, within the Los Vaqueros Watershed of Contra Costa County, …

A Comparison Of Current Anuran Monitoring Methods With Emphasis On The Accuracy Of Automatic Vocalization Detection Software, Jacob Douglas Eldridge

Masters Theses & Specialist Projects

Currently, a variety of methods are available to monitor anurans, and little standardization of methods exists. New methods to monitor anurans have become available over the past twenty years, including PVC pipe arrays used for tree frog capture and Automated Digital Recording Systems (ADRS) used to remotely monitor calling activity. In addition to ADRS, machine-learning computer software, automated vocalization recognition software (AVRS), has been developed to automatically detect vocalizations within digital sound recordings. The use of a combination of ADRS and AVRS shows the promise to reduce the number of people, time, and resources needed for an effective call survey …