Dissertation/Thesis Abstract

Movement Patterns in the Southern Flying Squirrel (Glaucomys volans) in Urbanized and Rural Environments
by Howard, Jeremy, M.S., Southern Illinois University at Edwardsville, 2019, 91; 13420265
Abstract (Summary)

As the human population continues to grow, urbanization and expansion continue into untouched areas causing fragmentation of forests. Fragmentation restructures a landscape and impacts a variety of flora and fauna, including small mammals. Fitness effects on small mammals caused by forest fragmentation is nuanced, but is negative overall. The New World flying squirrels (genus Glaucomys) in particular, with their direct link to forest trees for food, shelter, and travel, make a good model to understand the effects of fragmentation on forest mammals. This study examined the southern flying squirrel (Glaucomys volans) in urban and rural fragments in southwestern Illinois. Urban study sites were the three forest patches on the Southern Illinois University Edwardsville (SIUE) campus: Bluebell Woods, Sweet William Woods, and the Western Corridor. The rural study site is privately-owned land north of Edwardsville, IL (McCracken Woods). Squirrels were collared and tracked using radio-telemetry both nocturnally and diurnally. Nighttime tracking was done to establish home range sizes. Daytime tracking was used to determine nesting tree preference. It was predicted that (1) home range sizes will be greater for males than females, (2) trees selected for nesting will be predominantly hard mast trees and (3) of larger size (diameter), and (4) squirrel dispersal will be limited between patches. Home ranges were determined via two methods: 95% minimum convex polygon and 95% kernel estimator. A two-sample equal variance t-test was used to determine differences in male and female home range sizes. General comparisons for home range sizes were also done for site as well as in the context of other studies. Nesting tree preferences for hard mast vs. soft mast were tested via Fisher’s exact test.  Nesting tree diameter size preferences were tested via a Chi-Squared Goodness-of-Fit test. Gap crossing potential was determined via trigonometric calculations. Male squirrel home range sizes were not significantly different from female home range sizes. The minimum convex polygon (MCP) approach indicated squirrels on the SIUE campus had smaller home range sizes than those in McCracken Woods. The 95% kernel density estimator (KDE) indicated no difference among sites. Home ranges in the study were among the lowest described for both MCP and KDE. Low home range estimates may be due in part to some squirrels having a low number of observations (minimum = 5). Flying squirrels selected soft mast trees for nesting significantly more than expected. This preference may be due to greater cavity availability or food source seasonality. Tree size preferences were found to be significant in regard to medium and large trees (> 40 cm diameter) versus small trees (< 40 cm diameter). The finding of larger tree usage was consistent with most other studies. Finally, one male flying squirrel was found to cross between forest patches on the SIUE campus. This dispersal event involved crossing from the Western Corridor to Sweet William Woods through a gap bisected by a road. The most likely route was via a peninsula of trees that extended outward from the Western Corridor. This gap could have been crossed successfully through the air by flying squirrels with near average glide angles. Fire resistant tree plantings should occur to encourage successful crossing by more squirrels. Such a course of action will aid in reconnecting fragmented habitat patches for southern flying squirrels within the campus area. This study on movement patterns in southern flying squirrels in fragmented habitat can inform management practices throughout Illinois with potential benefits for other forest species.

Indexing (document details)
Advisor: Essner, Richard L.
Commitee: Brunkow, Paul E., Williams, Jason B.
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 58/05M(E), Masters Abstracts International
Subjects: Wildlife Conservation, Zoology
Publication Number: 13420265
ISBN: 978-1-392-17980-2
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