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Full-Text Articles in Life Sciences

Western Gulls’ (Larus Occidentalis) Reproductive And Behavioral Responses To Human Disturbance, Lilamarie 'Asta Bowen Jan 2023

Western Gulls’ (Larus Occidentalis) Reproductive And Behavioral Responses To Human Disturbance, Lilamarie 'Asta Bowen

Cal Poly Humboldt theses and projects

Human disturbances can negatively affect wildlife by causing stress, altering behavior, or even impacting populations through changes in survival or productivity. Colonial-nesting seabirds are of particular concern due to population declines and their gregarious and conspicuous nature, which may attract human visitors. However, the effects of nearby human activities, though frequently negative, could be neutral or even positive through phenomena like habituation to human activities or subsidization by human-supplied food sources. In this observational study, I evaluated relative support for three hypotheses which may explain how Western Gulls are impacted by human activity: disturbance, habituation, and subsidization. I investigated this …


Activity Patterns Of The Del Norte Salamander (Plethodon Elongatus): Monitoring Plethodontid Behavior Using Pit Tag Surveys, Sabrina Horrack Jan 2022

Activity Patterns Of The Del Norte Salamander (Plethodon Elongatus): Monitoring Plethodontid Behavior Using Pit Tag Surveys, Sabrina Horrack

Cal Poly Humboldt theses and projects

Semi-fossorial plethodontid salamanders exhibit behavioral plasticity to avoid desiccation, retreating underground to shelter from adverse conditions such as low precipitation and high temperatures. In this study, I used passive integrated transponder (PIT) tag surveys to monitor this behavior in the Del Norte salamander (Plethodon elongatus), a small plethodontid native to northwestern California and southwestern Oregon. Within its range, a climatic gradient exists in which coastal areas experience milder temperatures and high precipitation, while inland areas tend to have colder winters, hotter summers, and lower precipitation. By monitoring the activity patterns of this species in inland and coastal areas, …


An Ecomorphological Analysis Of Locomotion In Larvae And Neotenes Of Two Salamander Species: Dicamptodon Tenebrosus (Stream-Type) And Ambystoma Gracile (Pond-Type), Ethan Hardister Snee Jan 2020

An Ecomorphological Analysis Of Locomotion In Larvae And Neotenes Of Two Salamander Species: Dicamptodon Tenebrosus (Stream-Type) And Ambystoma Gracile (Pond-Type), Ethan Hardister Snee

Cal Poly Humboldt theses and projects

Morphology is the physical expression of a species’ evolutionary history and adaptation to its environment and as such is tied to ecology. Salamander larvae have historically been separated into "pond-type" and "stream-type" groups based on their morphology, however no studies have been performed quantifying the relationship between morphology and ecology. In this study I utilized in-situ behavioral observations, morphological measurements, and in-lab performance tests of Dicamptodon tenebrosus (stream-type) and Ambystoma gracile (pond-type) to examine the relationship between salamander larval morphology and ecology. In the field, behavior was video recorded during nighttime surveys; afterwards animals were captured and limb measurements were …