442 Works

Investigating unburned understory “halos” post-fire under blue oak (Quercus douglasii) canopies

Skyler Bennis, Sam Cormier, Angela Ma & Madeline Perreault
Oak trees profoundly impact California’s oak landscape biodiversity. Oaks influence growth in their understories and these community interactions have important ecological implications. Oaks can facilitate (positive) or interfere (negative) with understory productivity depending on tree characteristics such as variation in root morphology. Historically, California oak communities have been negatively affected by fire suppression, but they are now being impacted by increasing wildfire frequency. Despite their dominance in the woodland and savanna landscapes, there is a...

Mendocino meadow memory: legacy effects of land use on plant communities of Angelo Coast Range Reserve

Ary Sanchez-Amaya, Frida Perez, Jena Weinberger & Susan Glasser
Human alteration of landscapes has occurred consistently through actions such as development, tilling, agriculture, and fire management. Human land use can result in a legacy of exotic species dominance and increased competition, with negative impacts on native species richness and soil structure. Meadows within California have been affected by settlement due to their accessibility to humans and soil conditions that are ideal for agriculture. Prior to European settlement, meadows in Angelo Coast Range Reserve (ACRR)...

Defensive displays and chemical secretions of darkling beetles in the Mojave Desert

Tania Aguilar, , Meghan Proctor & Athena Schlereth
Many organisms often rely on chemical defenses to deter predators. However, the way in which invertebrates utilize chemical defenses has been relatively understudied. Darkling beetle species of the Eleodes and Coelocnemis genera exhibit defensive posturing followed by malodorous chemical secretions to signal their unpalatability towards potential predators. However, the metabolic costs and trade-offs associated with these mechanisms are unknown. It is also unclear whether certain beetle species utilize chemical defenses more readily than others. We...

A cross species analysis of various stressors among three pine species in the San Jacinto Mountains suggest Pinus jeffreyi is the most susceptible to environmental changes

Mona Broukhim, Benjamin Early & Luis Orozco Sanchez
Pine species in the southern fringes of their range are experiencing changes related to climatic pressures which may in turn affect their susceptibility to bark beetle invasions. These environmental stressors can lead to changes in a pines ability to produce resin as a defensive measure. This study of Pinus jeffreyi, Pinus coulteri, and Pinus lambertiana aims to identify the species of most concern and the overall health of the pines in the San Jacinto Mountains....

Acorn woodpecker (Melanerpes formicivorus) behavior varies in response to intra- and interspecific calls

Josephine Collier, Skye Hoolihan, Ethan Jakob & Hannah St. John
Acorn woodpeckers are a community-oriented species that, like other birds, uses and responds to vocalizations as a form of communication. The calls of certain competitors, predators, and intraspecific individuals change the behavior of a listener in different ways. The behaviors of three acorn woodpecker colonies were observed in response to four recordings: Steller’s jay, sharp-shinned hawk, an acorn woodpecker distress call, and a control. An ethogram was recorded for pre-call and post-call behavior of each...

Host tree circumference, litter depth, and slope affect snow plant (Sarcodes sanguinea) size at James San Jacinto Mountain Reserve

Sean Hinson & Mina Sadek
Plant-ectomycorrhizal relationships dominate temperate forest ecosystems, and for many Pinaceae tree species, this mutualistic relationship is an essential aspect of their ability to gather nutrients. The snow plant (Sarcodes sanguinea) is an ectomycorrhizal parasite that steals nutrients from host trees by accessing their root systems via the mycorrhizae. We examine microhabitat variables that affect snow plant size and phenology by measuring 5 snow plants within the James San Jacinto Mountain Reserve. We investigate the effects...

Abiotic differences and anthropogenic interference affect foothill yellow-legged frog breeding

Sharon Tamir, Anna Szymanska, Amanda Callahan, Gina Lucas & Jeniffer Amezquita
As human presence rapidly introduces novel environmental pressures to native ecosystems, many species experience population declines. Sensitive taxa such as amphibians may be particularly vulnerable to such environmental disturbances. Rana boylii, the foothill yellow-legged frog and a California State Species of Special Concern, serves as a model for understanding the effect of anthropogenic interference, such as changing climate and disturbed habitats, on reproductive success. In this study, we measured egg mass abundance, abiotic characteristics of...

The adaptive value of leaf quaking in Populus tremuloides

Natalie Kim, Mark Makar, Alexander Osleger & Juliana Shenouda
Some Populus species have evolved a flattened petiole that causes their leaves to quake in mild wind. In this study, we performed one observational study and two experimental studies on quaking aspen (Populus tremuloides) to investigate three predominant hypotheses on the adaptive value of quaking: (1) herbivory reduction, (2) light permeation, and (3) temperature maintenance. Overall, we found less insect herbivory on branches that quake less. We also found that quaking allows more light into...

Human-wildlife interactions in Anza-Borrego Desert State Park

Ninfa Negrete, Sara Ramirez & Robert Wong
Transportation infrastructure, such as roads and highways, supports human activity but negatively affect wildlife habitat, populations, and entire ecosystems (Bennet et. al 2011). As road networks continue to expand, animals lose habitat and are confined to isolated fragments, with the possibility of being enclosed by roads. Road effects like habitat fragmentation is not well known in state parks. This study aims to examine some of the effects of road disturbance on wildlife in the Anza-Borrego...

Exploring insect specialization on A. tridentata and A. rothrockii

Naomi Charlet, Elise Cypher, Anu Sethuraman & Tamar Viz
Invertebrates have been shown to specialize to different host environments, both with and without geographic isolation. Some plants emit volatile organic compounds (VOCs) to deter invertebrate herbivory. Specialist invertebrates have been shown to adapt to host plants regardless of VOC deterrents. Sagebrush (Artemisia spp.) is a plant which exhibits this damage-induced resistance. In the White Mountains, Artemisia tridentata and Artemisia rothrockii occupy the same general areas and are closely related yet differ in their chemistry...

Microhabitat selection of rock outcrops in yellow-bellied marmots (Marmota flaviventris)

Anne Burdette, Anna Catherine Klaassen, Mario Rodriguez &
The occupation of habitat by animals depends on their habitat preference as well as the accessibility of the space. Knowing how specific animals choose habitats, not only at large scales but also at micro scales, is critical to their conservation. We studied how yellow-bellied marmots (Marmota flaviventris) in the White Mountains, CA, choose between different rock outcrop microhabitats, using scat as a proxy for marmot abundance and density. We found that yellow-bellied marmots have no...

Predaceous diving beetles, Ilybius walsinghami, prefer organic debris for shelter in the San Jacinto Mountains, Indian Creek

Marley O’Connor, Emily Mun, Cole Dawdy & Isa Rosario-Martinez
Due to climatic changes, stream habitats are projected to be exposed to more frequent and intense floods. Floods can dramatically alter the stream ecosystem by lowering aquatic invertebrate abundance and richness, changing stream substrate composition, and impacting microhabitat availability. Depending on the substrate preferences of individual species, aquatic invertebrate populations could be impacted not only directly by floods, but also in their ability to re-populate highly altered stream habitats. In this study, we focused on...

Distribution and population estimates of the Borrego sand scorpion (Paruroctonus borregoensis)

Emma Korntheuer, Pearl Rakowski, Jack Choi & Sarkis Kasparian
Scorpions are important to the desert biome as prolific prey items, predators, and habitat modifiers. Our study set out to fill in the knowledge gap pertaining to the abundance and homing behavior of the Borrego dune scorpion, Paruroctonus borregoensi. A mark and recapture was conducted to determine if Borrego sand scorpions display site fidelity and as well as estimate population density in the Anza Borrego Desert in California. The Borrego sand scorpion displays no evidence...

Sisters or strangers: How does relatedness affect foraging in carpenter ants?

Lauren Hwang-Finkelman, Marissa Lopez, Alondra Murguia & Nathalie Treminio
Optimal foraging theory (OFT) states that animals will forage in a way that maximizes energy intake while minimizing energy expenditure. Eusocial insects are examples of species that exhibit OFT. One type of eusocial insect is the carpenter ant (Camponotus). Carpenter ants use pheromone trails as a form of communication. In using chemical cues to communicate with one another, carpenter ants fulfill OFT by maximizing energy rewards and minimizing energy spent searching for resources. We conducted...

Impacts of anthropogenic disturbance and insect abundance on Sonoran Desert bat activity

Amy Sue Law, , Emma McAndrews & Jess Stumpf
Rapid urbanization has been beneficial and detrimental to desert ecosystems. One group of organisms that are sensitive to such anthropogenic disturbance are bats. In this study, we examined bat abundance and composition in the Sonoran Desert in Southern California to assess how the bat community is affected by human disturbance and insect abundance. We observed bat calls and surveyed insect abundance at sites with high and low levels of human impact. We found that there...

Evidence of niche partitioning among small mammals in the Eastern Mojave Desert from scat distribution

Jacob Ferrall, Lucy Malamud-Roam, Roxana Ramirez &
Species that occupy similar ecological niches rely on niche partitioning to avoid direct competition. Our study aimed to detect niche partitioning between four abundant small mammal species residing in the Eastern Mojave Desert. By varying resource usage over space and time, the desert cottontail (Sylvilagus audubonii), the blacktailed jackrabbit (Lepus californicus), the desert woodrat (Neotoma lepida), and the white-tailed antelope squirrel (Ammospermophilus leucurus) are able to coexist along the mountains’ ridge. We investigated their niche...

Sex and tissue-specific evolution of developmental plasticity in Drosophila melanogaster

Didem Sarikaya
Developmental plasticity influences the size of adult tissues in insects. Tissues can have unique responses to environmental perturbation during development, however, the prevalence of within species evolution of tissue-specific developmental plasticity remains unclear. To address this, we studied the effects of temperature and nutrition on wing and femur size in D. melanogaster populations from a temperate and tropical region. Wings were more sensitive to temperature, while wings and femurs were equally responsive to nutrition in...

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