Graduate Thesis Or Dissertation
 

Temporal and Spatial Dynamics of Avian Utilization and Community Composition in Willamette Valley Wetland Study Sites: A Comparative Analysis of Winter Seasons in 1995 and 2019

公开 Deposited

可下载的内容

下载PDF文件
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/70795h61w

Descriptions

Attribute NameValues
Creator
Abstract
  • Resident and migratory avifauna in the Willamette Valley, Oregon are heavily influenced by winter conditions and habitat characteristics, especially those of wetlands. As such, it is important to monitor avian communities and environmental factors at wetland sites within the Willamette Valley during winter. Using data from standardized avian point-count surveys, landcover aerial-imagery, and observed conditions, I describe the passerine species compositions of 20 mid-Willamette Valley wetland sites in the winters (January-March) of 1995 and 2019, examine how these compositions changed between 1995 and 2019, and determine what landscape and conditional variables were present and how they differed between 1995 and 2019. Abundance and diversity measurements at a site were positively correlated, as were a species’ spatial expanse and the frequency in which that species occurred through the winter. Some species showed site fidelity, preferring some sites to others. In 1995; California Scrub-Jay, Dark-eyed Junco, Golden-crowned Kinglet, and Yellow-rumped Warbler exhibited site fidelity to some sites, as did Black-Capped Chickadee, Eurasian Collared-Dove, Lesser Goldfinch, and White-crowned Sparrow in 2019. On the species level, more individuals of American Robin, American Crow, European Starling, Red-winged Blackbird, Song Sparrow, and Spotted Towhee were detected at the sites in 2019 than in 1995, while fewer Golden-crowned Kinglets were detected in 2019. Community metrics did not differ significantly between these two years, indicating the general health of the sites has not deteriorated or improved to a point that affected overall species richness, rarity-weighted richness, or abundance. Species composition and community metrics could be influenced by the landcover type and the conditions at and around the sites. At the greatest spatial scales (1-km & 500-m buffer zones) woody wetland area increased the most while grassland/herbaceous area decreased the most. At the smallest examined scale (100-m) low-intensity development increased the most and forested area (mostly deciduous forest) decreased the most. These findings can help inform land managers, scientists, and conservationists about local land use changes and avian species and community changes. Stakeholders can use these results to inform conservation decisions and allocate resources efficiently to help support avian and ecological success in the Willamette Valley as it continues to change.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
权利声明
Publisher
Peer Reviewed
Language
File Format

关联

Parents:

This work has no parents.

属于 Collection:

单件

缩略图 标题 上传日期 公开度 行动
file details ZimmermanMarisaA2023.pdf 2023-11-03 公开 下载