Wildlife Road Mortality on the 1000 Islands Parkway in South Eastern Ontario: Peak Times, Hot Spots, and Mitigation Using Drainage Culverts

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Garrah, Evelyn
Road Mortality , Drainage Culvert , Wildlife Mortality Hot Spot , Turtle Conservation
Road mortality threatens the long-term viability of some wildlife populations, particularly herpetofauna. Wildlife road mortalities were recorded during regular bicycle-based surveys of the 1000 Islands Parkway in south eastern Ontario during 2010 and 2011. These data were grouped with similar data collected in 2008 and 2009 to determine when and where animals were killed along the Parkway to better inform mitigation options. Temporal and spatial clustering was significant for five taxonomic groups: snakes were found dead on the road primarily in September, turtles in June, frogs in July, and birds and mammals in June and July. The majority of turtles found on the Parkway were adult females, which may have implications for long-term population demographics and persistence. Regression tree analysis indicates day-of-year as the most important variable in explaining wildlife road mortality for all taxonomic groups, with higher road mortalities coinciding with higher minimum daily temperature. Precipitation and traffic accounted for little variation in snake road mortality, and had no effect on turtle, frog, bird or mammal road kills. Spatial clustering was found for all taxonomic groups with overlapping areas of significant clustering between years identified as hot spots. In addition, the potential for drainage culverts to reduce wildlife road mortality was tested with two experimental treatments in 2010: (1) blocked culverts to prevent wildlife use, and (2) drift fence installation adjacent to culverts to encourage wildlife use. Wildlife road mortalities at these locations as well as control culverts were compared with 2008 wildlife road mortalities when there were no culvert treatments. The number of road kills in the area of treatments was too low to measure changes for all taxa but frogs, which showed no significant changes in road kills for any culvert treatment. The results of the study are used to evaluate a list of potential options for mitigating wildlife road mortality along the Parkway, and a list of implementable actions is identified.
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