Chapter 9
Relative Risk and Variables Associated
with Bear and Ungulate Mortalities Along
a Railroad in the Canadian Rocky
Mountains
Benjamin P. Dorsey, Anthony Clevenger and Lisa J. Rew
Abstract Train-wildlife collisions can impact wildlife populations as well as create
human and resource management challenges along railways. We identified locations and
railroad design features associated with train-wildlife collisions (strikes) on a 134 km
section of the Canadian Pacific Railroad (CPR) that travels through the Banff and Yoho
National Parks. A 21-year dataset of train strikes with elk (Cervus elaphus), deer
(Odocoileus spp.), American black bears (Ursus americanus) and grizzly bears (U.
arctos) were compared to relative abundance estimates, and nine train and railroad
variables. Train strikes and relative abundance varied spatially for elk, deer and bears.
Hotspots and relative risk estimates were used to identify potential problem locations.
Hotspots were defined as segments of the train line where strike counts were above the
95% confidence interval based on a Poisson distribution, and could be identified for elk
and deer but not bears. Relative risk was estimated as the ratio of strike counts to that
expected based on relative abundance. High relative risk locations, where more strikes
occurred than were expected, were identified for elk, deer, and bears. Relative abundance
was positively correlated with strikes for elk and deer but not bears. Train speed limit was
positively associated with strikes for elk and deer. For bears, the number of structures (e.g.,
overpasses, tunnels, snow sheds and rock cuts) and bridges were positively correlated to
strikes. To reduce the risk of train strikes on wildlife, our management recommendations
include train speed reduction, habitat modifications and railroad design alterations.
Keywords Animal collision mortality Á Grain spillage Á Railroad Á Relative risk Á
Transportation corridor
B.P. Dorsey (&)
Parks Canada, Revelstoke, BC V0E 2S0, Canada
e-mail: bpdorsey@gmail.com
A. Clevenger
Western Transportation Institute, College of Engineering, Montana State University,
334 Leon Johnson, Bozeman, MT 59717, USA
L.J. Rew
Land Resources and Environmental Sciences, Montana State University,
334 Leon Johnson, Bozeman, MT 59717, USA
© The Author(s) 2017
L. Borda-de-Água et al. (eds.), Railway Ecology,
DOI 10.1007/978-3-319-57496-7_9
135
Relative Risk and Variables Associated
with Bear and Ungulate Mortalities Along
a Railroad in the Canadian Rocky
Mountains
Benjamin P. Dorsey, Anthony Clevenger and Lisa J. Rew
Abstract Train-wildlife collisions can impact wildlife populations as well as create
human and resource management challenges along railways. We identified locations and
railroad design features associated with train-wildlife collisions (strikes) on a 134 km
section of the Canadian Pacific Railroad (CPR) that travels through the Banff and Yoho
National Parks. A 21-year dataset of train strikes with elk (Cervus elaphus), deer
(Odocoileus spp.), American black bears (Ursus americanus) and grizzly bears (U.
arctos) were compared to relative abundance estimates, and nine train and railroad
variables. Train strikes and relative abundance varied spatially for elk, deer and bears.
Hotspots and relative risk estimates were used to identify potential problem locations.
Hotspots were defined as segments of the train line where strike counts were above the
95% confidence interval based on a Poisson distribution, and could be identified for elk
and deer but not bears. Relative risk was estimated as the ratio of strike counts to that
expected based on relative abundance. High relative risk locations, where more strikes
occurred than were expected, were identified for elk, deer, and bears. Relative abundance
was positively correlated with strikes for elk and deer but not bears. Train speed limit was
positively associated with strikes for elk and deer. For bears, the number of structures (e.g.,
overpasses, tunnels, snow sheds and rock cuts) and bridges were positively correlated to
strikes. To reduce the risk of train strikes on wildlife, our management recommendations
include train speed reduction, habitat modifications and railroad design alterations.
Keywords Animal collision mortality Á Grain spillage Á Railroad Á Relative risk Á
Transportation corridor
B.P. Dorsey (&)
Parks Canada, Revelstoke, BC V0E 2S0, Canada
e-mail: bpdorsey@gmail.com
A. Clevenger
Western Transportation Institute, College of Engineering, Montana State University,
334 Leon Johnson, Bozeman, MT 59717, USA
L.J. Rew
Land Resources and Environmental Sciences, Montana State University,
334 Leon Johnson, Bozeman, MT 59717, USA
© The Author(s) 2017
L. Borda-de-Água et al. (eds.), Railway Ecology,
DOI 10.1007/978-3-319-57496-7_9
135