Available at: https://digitalcommons.calpoly.edu/theses/3218
Date of Award
12-2025
Degree Name
MS in Biological Sciences
Department/Program
Biological Sciences
College
College of Science and Mathematics
Advisor
Clinton Francis
Advisor Department
Biological Sciences
Advisor College
College of Science and Mathematics
Abstract
Humans are altering the environment in varied and widespread ways. Increasing urban and agricultural development causes changes to habitat and resource availability as well as changes to the sensory environment via light and noise pollution. Climate change also causes more extreme temperature anomalies, storms, and droughts that challenge birds in a multitude of ways. In this thesis, we assessed these impacts of these changes on a local and continental scale. In the first chapter, we assessed the impact of natural, anthropic, and structural characteristics of viticultural land on both taxonomic and structural avian diversity. Loss of habitat from agriculture is a major contributor to bird population decline in North America therefore it is vital that we encourage diverse and resilient bird communities within vineyards and take advantage of natural pest management that birds can provide. Vineyard cover is increasing in San Luis Obispo, covering over 18,000 hectares, so this is also an issue of local importance. Increasing canopy cover in viticultural landscapes appears overwhelmingly to be the most effective way to increase avian taxonomic and functional community diversity; however, adding land cover and structural variation in general may also help. In the second chapter, we took a bigger picture approach and assessed the impact of changing climate and light pollution on avian phenology in North America. Breeding phenology can have vast impacts on a bird’s fitness as a mismatch with resource availability can cause decreases in productivity, contributing to the overall decline in avian populations. We used a long-term bird banding dataset from the Monitoring Avian Productivity and Survivorship program to assess changes in bird breeding phenology and whether certain characteristics of the species impact their sensitivity to these changes in the environment. Species with a cooler thermal niche appear to be more sensitive to increasing temperature anomalies, and both smaller species and species with better dim light vision were more sensitive to increasing light pollution. The variation in phenological response exhibited by these species could reflect growing phenological asynchrony that can have major consequences for bird populations as both climate change and light pollution continue to disrupt the natural environment. Together, these two projects provide an assessment of both local and large-scale challenges that birds face in an increasingly human-impacted world.