Life Sciences Commons^™

Automated Tree Mortality Detection Using Ubiquitously Available Public Data, Michael T. Huggins

Master's Theses

Understanding the dynamic interplay between fire severity, topography, and tree mortality, is crucial for predicting future forest dynamics and enhancing resilience against climate change-induced wildfire regimes. This thesis develops a multi-sensor approach for automated estimation of tree mortality, then applies it to examine trends in tree mortality over a six-year period across a fire affected study site in the Trinity River basin in Northern California. The Random Forest model uses publicly available USGS 3D Elevation Program Lidar (3DEP) and NAIP imagery as inputs and is likely to be easily adaptable to other landscapes. The model had a Receiver Operating Characteristic …

Distribution And Ecological Function Of Pacific Lamprey In The San Luis Obispo Creek Watershed, Parker Kalan

Master's Theses

Pacific lamprey (Entosphenus tridentatus) is an endemic species to coastal watersheds along the Pacific Rim in North America and Asia. The species' geographic distribution is retracting and has not been mapped precisely, and the ability for the species to provide ecosystem services, such as water filtration, for supporting watershed management has not been tested. The San Luis Obispo Creek watershed, California, USA is at the southern end of Pacific lamprey’s retracting distribution, and the San Luis Obispo watershed is impacted by degraded water quality, making investigation of Pacific lamprey in the San Luis Obispo Creek watershed of direct …

Phytoplankton Community Response To Changing Environmental Conditions Across Two Central California Sites, Nicholas Soares

Biological Sciences

Understanding the role that changing environmental conditions play in altering phytoplankton abundance and community composition, and in turn ecosystem structure and function, will be increasingly important for the sustainable use and management of ocean resources in a changing climate. Characterizing change in nearshore ecosystems requires long-term studies with a broad spatial extent, with most studies sacrificing spatial extent for temporal duration. However, phytoplankton and ecosystem response can vary substantially over small spatial scales due to local oceanographic forcing and anthropogenic influence, making the application of long-term data from one site to another in the same geographic vicinity potentially challenging. In …

Glycolic Acid Utilization In Two Species Of Marine Bacteria, Erik S. Timsak

STAR Program Research Presentations

Interactions between bacteria and phytoplankton are crucial for the cycling of organic matter in marine environments. Around 50% of organic carbon taken up by marine bacteria is converted into inorganic carbon. The uptake of organic carbon by marine bacteria exuded from phytoplankton is a key factor in regulating the marine carbon cycle. One such molecule that is exuded by phytoplankton and then uptaken by marine bacteria is called glycolate - the anion of glycolic acid, a two caron molecule. Glycolate is exuded by phytoplankton during photorespiration and 10-50% of dissolved organic carbon in marine environments is comprised of glycolate. Additionally, …

Effects Of Habitat Restoration On Soil Retention On Santa Rosa Island, Michael Perez, Kathryn Mceachern, Ken Niessen

STAR Program Research Presentations

Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered substrate integrity as the land became denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog common to the island. This experiment sought to determine whether sediment is being lost or deposited on a ridge in the middle of the island containing a grove of Q. tomentella …

Weights And Balances: Integrating Models For Prevention And Response To Southern California Offshore Oil Spills, Carmen Watts Clayton, Amoret Bunn

STAR Program Research Presentations

Licensing offshore oil and gas reserves in the United States waters are overseen by the U.S. Department of the Interior’s Bureau of Safety and Enforcement (BSEE). The licensing application includes planning for any worst-case oil spill scenario between BSEE and the applicant based on lessons learned from historic offshore spills such as the Deepwater Horizon (2010), Exxon Valdez (1989), and the Union Oil Platform Blowout (1969). The process for planning to respond to oil spills involves coordination with multiple agencies, trustees, and stakeholders to ensure that oil spill responses consider multiple factors, including ecologically sensitive species, commercial transportation and fisheries, …

Studying The Effects Of Serpentine Soil On Adapted And Non-Adapted Species Using Arduino Technology, Kiana Saniee, Edward Himelblau, Brian Paavo

STAR Program Research Presentations

Abstract: Serpentine soils are formed from ultramafic rocks and are represent an extreme environment for plants. Serpentine soils are unique in that they carry high concentrations of heavy metals, are nutrient deficient, particularly in calcium, and have poor water retention capabilities. Although these soils constitute harsh conditions for plant growth, there are a number of species that are adapted and even endemic to serpentine soil. Water retention by commercial potting mix was compared with serpentine soil. Also, serpentine adapted and non-adapted species were grown in both soil treatments and physiological data were collected. We used the Arduino electronic platform to …

To Fish Or Not To Fish? What Effect Do California’S Marine Protected Areas Have On Up-And-Coming Kellet’S Whelk Fishery?, Jennifer Greene

STAR Program Research Presentations

Kellet’s whelk, Kelletia kelletii, were observed at sample sites throughout their range from Baja California, Mexico, to Monterey, CA to determine patterns of population density. Sample sites in each region were either located within California marine protected areas where take of the Kellet’s whelk in prohibited, or in non-protected areas where the whelks can be fished both commercially and recreationally. Kellet’s whelk population density was compared between all MPA and non-MPA sample sites. These mean densities were also found for sites in Santa Barbara and San Diego near active fishing ports and compared to data from the same sites collected …

Effects Of Soil Erosion Barriers On Percent Cover And Sediment Size, Michael Perez

STAR Program Research Presentations

Ranching began on Santa Rosa Island in the 1840’s, introducing nonnative megafauna that put selective grazing pressures on endemic species. Dense groves of island oak (Q. tomentella) are aid in sediment deposition and retention. A current restoration effort, involved installing soil erosion barriers, known as wattles, to prevent sediment from being lost upslope and recruit plant growth whose root systems could further stabilize the slope. This experiment was designed to compare percent cover of vegetation growth in areas with and without soil erosion barriers. This was done using the line intercept method (n=42) on three meter transects, measuring …

Stress Ecology Of The Pacific Rattlesnakes (Crotalus Oreganus And Crotalus Helleri), Natalie Claunch

Master's Theses

Stress is a physiological state induced by disturbance or adverse environmental conditions and is modulated by the glucocorticoid hormone corticosterone (CORT) in reptiles. Stressors can have various impacts on vertebrate trait expression and may affect survival or reproduction. Little is known about the effects of chronically elevated CORT in free-ranging reptiles, or the effect of disturbance stress on venom composition in captive snakes.

In chapter 1, we investigated the effects of researcher induced disturbance on CORT levels and venom composition in a group of captive Northern Pacific rattlesnakes (Crotalus oreganus). Venom protein concentration and plasma CORT levels were …

An Invasive Grass And A Desert Adapted Rodent: Is There An Effect On Locomotory Performance And Is It Modified By Prior Experience Or Familiarization?, Camille D. Boag

Master's Theses

Kangaroo rats (Dipodomys spp.) are frequently characterized as keystone species for their role in altering soil characteristics, changing habitat structure through seed consumption and dispersal, and being important primary consumers in their ecosystem. They are arid adapted and known to forage in areas with sparse vegetation. Studies suggests densely vegetated habitat to be unsuitable for kangaroo rats because plants are an impediment to their locomotion and predator avoidance behaviors. This study focuses on an invasive grass, South African Veldt (Ehrharta calycina), that converts landscapes with sparse vegetation into dense grassland habitats, and the Lompoc kangaroo rat …

Sediment Loss Of Santa Rosa Island Slopes: An Erosional Study, Michael Perez

STAR Program Research Presentations

Ranching began on Santa Rosa Island in the 1840’s, consequently introducing nonnative megafauna that put novel selective grazing pressures on endemic plant species. Their movement patterns also altered sediment integrity as the land was denuded of any stabilizing vegetation. Dense groves of island oak (Q. tomentella) are known to aid in sediment deposition and retention. The groves also function to collect water during periods of intense fog that are common to the island. This experiment sought to quantify the volume of sediment that has been lost on a south facing slope in the middle of the island that …

Do Marine Protected Areas Affect Emerging Fisheries Population Density?, Jennifer Greene, Katherine O. Grady, Crow White, Danielle Zacherl

STAR Program Research Presentations

Kellet’s whelk, Kelletia kelletii, were observed at sample sites throughout their range from Baja California, Mexico, to Monterey, CA to determine patterns of population density. Sample sites in each region were either located within California marine protected areas where take of the Kellet’s whelk in prohibited, or in non-protected areas where the whelks can be fished both commercially and recreationally. Kellet’s whelk population density was compared between all MPA and non-MPA sample sites. These mean densities were also found for sites in Santa Barbara and San Diego near active fishing ports and compared to data from the same sites collected …

Feeding Ecology Of Delta Smelt During A Seasonal Pulse Of Turbidity, William A. Hilton, Aaron Johnson, Wim Kimmerer

STAR Program Research Presentations

The delta smelt (Hypomesus transpacificus) is a small, pelagic fish endemic to the San Francisco Estuary (SFE) and protected under federal and state endangered species acts. This study examines the diet of adult delta smelt during their spawning migration in the winters of 2010 and 2012. Delta smelt and their zooplankton prey were sampled concurrently during a seasonal pulse of turbidity at sites along their migratory route from the low salinity zone in Suisun Bay to the fresher waters of the Sacramento/San Joaquin Delta. Gut contents were identified to the lowest possible taxon and counted, along with zooplankton …

The Large Genome Constraint Hypothesis: Evolution, Ecology And Phenotype, Charles A. Knight, Nicole A. Molinari, Dmitri A. Petrov

Biological Sciences

• Background and Aims If large genomes are truly saturated with unnecessary ‘junk’ DNA, it would seem natural that there would be costs associated with accumulation and replication of this excess DNA. Here we examine the available evidence to support this hypothesis, which we term the ‘large genome constraint’. We examine the large genome constraint at three scales: evolution, ecology, and the plant phenotype.

• Scope In evolution, we tested the hypothesis that plant lineages with large genomes are diversifying more slowly. We found that genera with large genomes are less likely to be highly specious – suggesting a large …