Ecology and conservation of prairie rattlesnakes (Crotalus viridis viridis) in relation to movement in a fragmented urban environment
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Date
2010
Authors
Andrus, Wonnita
University of Lethbridge. Faculty of Arts and Science
Journal Title
Journal ISSN
Volume Title
Publisher
Lethbridge, Alta. : University of Lethbridge, Dept. of Biological, c2010
Abstract
Eighteen prairie rattlesnakes (Crotalus viridis viridis) were tracked using radio-telemetry and 82
snakes were PIT-tagged over a 2-year period in Lethbridge, AB to determine population size,
movement patterns, and habitat utilization, and to predict fragmentation effects on the species
within an urban locale. Population size was estimated using closed population models at 374
snakes (295 adults) and open population models at 204 snakes (161 adults), greater than an
estimate of <50 adults in 2003 (Ernst, 2003) and 2006 (Ernst & Quinlan, 2006).
Mean home range sizes, based on 95% minimum convex polygon analysis, differed significantly
between years (31.51 ha in 2005, 3.72 ha in 2006). Calculated movement parameters, such as
mean distance moved per day, total distance moved over the course of the active season, and
frequency of movement varied between years and individuals. Greater-than-expected (under
hypotheses of even habitat choice) utilization was observed in habitat types located within coulee
and flood plain areas, with apparent preference towards unbroken parcels of grassland or
cottonwoods, whereas less-than-predicted utilization of agricultural habitat type was observed.
Fragmentation effects on prairie rattlesnake movement and occurrence were examined through
modeling and were found to coincide with observed species’ locations, suggesting that prairie
rattlesnakes are undergoing modification of movement patterns to avoid highly concentrated
human density or use. Influence of weather on the use of vegetative ground cover was observed,
as it was accessed more by prairie rattlesnakes at higher temperatures.
Recommendations towards future management of the prairie rattlesnake population in Lethbridge
are given, including protection of the Bridge View Drive site and inclusion of varied habitat types
and terrain when planning habitat and wildlife corridors. Management decisions that ensure
remaining habitat parcels and connective areas near rattlesnake foraging or movement corridors
are also advocated. Identification of future research focuses include studies on juvenile
survivorship, genetic structure, and vehicle-related mortality.
Description
xii, 83 leaves : col. ill., col. maps ; 29 cm
Keywords
Prairie rattlesnake -- Habitat -- Conservation -- Alberta -- Lethbridge , Prairie rattlesnake -- Home range -- Research -- Alberta -- Lethbridge , Prairie rattlesnake -- Radio tracking -- Alberta -- Lethbridge , Prairie rattlesnake -- Effect of habitat modification on -- Research -- Alberta -- Lethbridge , Prairie rattlesnake -- Research -- Alberta -- Lethbridge , Fragmented landscapes -- Research -- Alberta -- Lethbridge , Dissertations, Academic