Negative effects of roads on wildlife include mortality caused by attempted road crossings. The most common method to choose locations for road kill mitigation is to identify hotspots of current road mortality. We evaluated the effect of traffic volume on current road kill hotspots. We used a road kill survey to test for differential traffic effects on road kill by taxonomic group, controlling for effects of habitat. Anuran road kill was negatively related, whereas bird road kill was positively related, to traffic volume. The negative effects of traffic on the birds are at broader spatial extents than we measured, and effective mitigation could be directed by hotspot analysis at this scale. Decreased anuran road kill with increasing traffic volume could be caused by road avoidance or depressed populations, but focusing mitigation efforts on anuran road kill hotspots may ignore populations that have been reduced by past traffic‐related mortality. Road kill hotspot analyses should therefore be used with caution when evaluating mitigation options, since when past mortality reduces populations (e.g., Bouchard et al. 2009, in this region), current road kill numbers can be smallest in precisely the sites with the greatest historical road impact on the population size. Sites with high traffic volume in locations where wildlife habitat is near the road, and particularly where it straddles the road, will often correspond with road kill hotspots, but instances where there is good habitat but low current road kill can indicate particularly important locations for mitigation to restore populations. © 2013 The Wildlife Society.

Strategies to reduce wildlife road mortality have become a significant component of many conservation efforts. However, their success depends on knowledge of the temporal and spatial patterns of mortality. We studied these patterns along the 1000 Islands Parkway in Ontario, Canada, a 37 km road that runs adjacent to the St. Lawrence River and bisects the Algonquin-to-Adirondacks international conservation corridor. Characteristics of all vertebrate road kill were recorded during 209 bicycle surveys conducted from 2008 to 2011. We estimate that over 16,700 vertebrates are killed on the road from April to October each year; most are amphibians, but high numbers of birds, mammals, and reptiles were also found, including six reptiles considered at-risk in Canada. Regression tree analysis was used to assess the importance of seasonality, weather, and traffic on road kill magnitude. All taxa except mammals exhibited distinct temporal peaks corresponding to phases in annual life cycles. Variations in weather and traffic were only important outside these peak times. Getis-Ord analysis was used to identify spatial clusters of mortality. Hot spots were found in all years for all taxa, but locations varied annually. A significant spatial association was found between multiyear hot spots and wetlands. The results underscore the notion that multi-species conservation efforts must account for differences in the seasonality of road mortality among species and that multiple years of data are necessary to identify locations where the greatest conservation good can be achieved. This information can be used to inform mitigation strategies with implications for conservation at regional scales.

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The effects of roads on animal mortality are of increasing concern as environments are increasingly impacted by road development and traffic. This animal road kill study took place on the Thousand Islands Parkway, near St.Lawrence Islands National Park. The survey route was traveled by bicycle and over 6682 kills were located. There were 63 unique species identified, 3 were special concern and 2 were threatened as designated by the Committee on the Status of Wildlife in Canada. Data were analyzed using kernel density to visually identify hotspots, network K-function for statistical clustering, and roving window analysis to analyze relationships between road kill and various predictor variables including traffic volume. Although the landscape along the study route did not vary greatly, traffic volume was negatively associated with frog and toad kills, implying that populations have been depressed. Therefore, mitigation efforts should consider possible past habitats as well as current mortality hotspots. AcknowledgementsI would like to thank Dr. Scott Mitchell for his supervision and Dr. Lenore Fahrig for helping guide the research and stimulate my interest in this subject area. Also, I would like to thank Parks Canada for funding this research.