Plastic Pollution and Effective Reduction Policies

College of Natural Resources & Sciences

During the International Mathematical Contest in Modeling, our team tackled the problem of the destructive accumulation of plastic in the earth's land and waterways. We researched national and international policies attempting to curb the production and consumption of plastic, and constructed a simple model to predict plastic mass growth in the future, under various parameters and scenarios.

Plastics in the Gut's of Leach's Storm Petrels in Humboldt County, California

College of Natural Resources & Sciences

For this project, we looked at the plastics that were found in the Guts of Leach's Strom Petrels in Humboldt County, CA. In 2020, 57 of these storm petrels were found dead of natural causes and stored at Cal Poly Humboldt. In my project, I analyze if these storm petrels had plastics in their stomachs at the time of their death, and if so, how much plastic. This is the first of such studies done on Leach's Storm Petrels on the Pacific Coast. The results help to contribute to the ever-growing knowledge of how plastics in our oceans are affecting wildlife.

Plethodontid Salamander Microhabitat Selection

Freya Prissberg, Wildlife Undergraduate Student

College of Natural Resources & Sciences

My research is done on Ensatina and California slender salamander microhabitat selection in the Arcata Community Forest. Soil moisture, canopy cover, soil temperature, cover object length/width, foliage cover and salamander length and weight were all recorded. This data was used to determine if Ensatina and California slender salamanders show microhabitat selection for certain soil temperature, soil moisture, canopy cover or foliage cover.

Plethodontid Salamander Proximity to Surface Water Relative to Ocean Distance

College of Natural Resources & Sciences

My research was conducted on the coast of Humboldt County, where I measured salamander proximity to a freshwater source relative to the distance to the ocean. I used two study sites, one in the Arcata Community Forest and one in Trinidad. I found 38 salamanders while sampling 60 1x1 meter quadrats.

Pollinator Response to Ultraviolet Light Reflection in Flowers

Carina Trentini, Wildlife Undergraduate Student

College of Natural Resources & Sciences

This research project was a the capstone project for my Wildife degree, in which I researched the impact short-wave UV light reflection by flowers affects pollinator behavior. Insects can see into the ultraviolet light spectrum, and plants are known to reflect these light wavelengths for aiding pollinators. I studied the correlation between pollinator visitation frequency and the proportion of flower surface area that is reflective of UV light. I focused on 3 main pollinator groups: bumble bees, native bees and flower flies. I found that pollinators are significantly more likley to visit flowers with high UV light reflection than flowers with low amounts of UV light reflection.

Post-Fire Seedling Recruitment by Burnt Trees at the 2017 Helena Fire

College of Natural Resources & Sciences

A regeneration survey was conducted in Weaverville by the 2019 Forest Ecology class at the 2017 Helena Fire students looking at post-fire seedling recruitment. Forty five 10-meter radius plots were established. Within the plots, seedlings and fallen seed cones were counted. We assumed that the seeds were mature when this site burned (August 31) and that all seedlings came from burnt trees; i.e. the seeds within the cones survived the flames. Thus, we hypothesized there would be a positive relationship between seedling and seed cone density. The results showed a positive correlation (R2 = 0.82) between seedlings and seed cones per plot, thus sustaining our hypothesis.

Post-fire seedling recruitment in the 2008 Siskiyou complex fire

College of Natural Resources & Sciences

The spate of recent high intensity (stand-replacing) fires in California has led some to wonder whether our tree species are adapted to such large burns. Many assume that regeneration will typically be so poor that many of these burns will be dominated by shrubs and herbs instead of forests. This study examines seedling recruitment of conifers as a function of distance across a 1 km-wide burn near Hoopa. Six transects, each 50 m x 4 m, were spaced along the 1 km transects, and seedlings and burnt cones were counted. Douglas-fir and white fir averaged 2903 ha-1 and 1996 ha-1 seedlings, respectively, and 75% of the km had >490 recruits/ha (the minimal acceptable density in California).

Post-Wildland Fire Prescribed Burning: Regeneration of Ponderosa Pine and Changes in Fuel Loads Following the Jasper Fire

Cristina Winters, Forestry, Fire & Rangeland Management Undergraduate Student

College of Natural Resources & Sciences

As high-intensity wildland fires occur more frequently and increase in size, the occurrence of reburn in burn scars is also increasing; however, the ecological effects of such reburn in Western coniferous forests are not well understood. Post-prescribed fire, we investigate the changes in woody fuel loads in high and moderately burned areas of the 2000 Jasper Fire and the patterns of ponderosa pine regeneration survival in those areas. Our findings can inform a management plan to restore historic heterogeneity in the Black Hills, a culturally and economically important region of the U.S., and increase resistance and resilience to climate change.

Predicting Phosphorus Retention in Two Volcanic-Derived Forest Soils of Northern California

College of Natural Resources & Sciences

Plant available phosphorus (P) occurs in anionic forms which become plant-unavailable ("fixed" or "retained") when iron and aluminum oxides form insoluble phosphate complexes. P-retention is especially likely to occur under acid conditions in soils containing short range order (SRO; poorly crystalline) materials, namely allophane and imogolite. This set of characteristics is common in volcanic-derived forest soils in Pacific Northwest timber regions. We built upon 25 years of research by investigating phosphorus retention on two well-studied sites, Whitmore and Feather Falls. Simple soil assays were used in a mixed-effects model to predict P-retention on these soils.

Predicting Renewable Energy Usage with Linear Regression and Time-Series Analysis

College of Natural Resources & Sciences

For California, Arizona, New Mexico, and Texas, increasing renewable energy production and consumption is important in the face of climate change. We develop a model to analyze these states’ current renewable energy production and future projection. Findings from the model could lead to policy changes in favor of renewable energy.