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Title:Anthropogenic environmental change and habitat occupancy by riparian muskrats in a Midwestern landscape
Author(s):Bucci, Lisa A.
Advisor(s):Schooley, Robert L.
Department / Program:Natural Resources and Environmental Sciences
Discipline:Natural Resources and Environmental Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Ondatra zibethicus
landscape ecology
occupancy modeling
urban adapter
Phalaris arundinacea
imperfect detection
predictive habitat model
Abstract:Increased urban land cover and more intensive agriculture in the Midwest have changed the landscape for wildlife species. Distributions of semi-aquatic mammals such as muskrats (Ondatra zibethicus) may respond to environmental changes including increased urbanization, alteration of hydrology, introduction of invasive species, and changes in predator communities. The response of muskrat populations to landscape and local-scale changes is important for the conservation of this economically-valuable furbearer species. I completed multiple surveys for occupancy by muskrats at 90 sites in central Illinois in 2007 and 2008. Sites were stratified based on urbanization levels. Occupancy was determined by presence of tracks, scat, and feeding sign in 200-m stream segments that approximated a home-range scale. I calculated detection probabilities to determine the likelihood of false absences. The per-survey detection probability was 0.79 (SE = 0.04) in 2007 and 0.76 (SE = 0.04) in 2008. Detection was related positively to Julian date and negatively to wood debris abundance. Muskrats occurred more often at sites with a greater percentage of developed landcover, as well as in wider and deeper streams that drained more area. Year-to-year turnover was explained by water availability and measures of stream size. Although invasive reed canary grass was the dominant species at an average of 2.3 (SE = 0.20) out of 5 habitat sampling stations per site, it did not affect site occupancy or turnover. Occupancy patterns may be related to lower predation risk near human development and in wider, deeper streams. Overall, muskrat distribution was related to local and landscape variables and was insensitive to some aspects of environmental change.
Issue Date:2010-01-06
Rights Information:Copyright 2009 Lisa A. Bucci
Date Available in IDEALS:2010-01-06
Date Deposited:December 2

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