Protecting Grizzly Bears from Trains in the Mountain Parks
A grizzly bear on the tracks in Banff National Park. Photo: Niels de Nijs
Ten years ago, Mike Gibeau, then the carnivore biologist for Banff National Park, identified a problem: collisions between grizzly bears and trains were increasingly prevalent. Between 2000 and 2010, ten grizzly bears there were struck and killed by trains and several more unconfirmed strikes were reported.[1] That made train strikes the leading cause of mortality for this population just as grizzly bears were designated in Alberta as a threatened species.
“We found diverse sources of bear-attracting food on or near the rail that included tonnes of grain spilled by hopper cars.”
Rising rates of bear mortality inspired Jim Pissot, an environmental activist in Canmore, to try to stop the problem with relentless advocacy. Fred Green, then CEO of Canadian Pacific Railways, addressed the problem with a research and funding vision. Leanne Allison and Jeremy Mendes engaged the public by revealing the train-caused fate of a grizzly matriarch with an evocative, award-winning documentary, Bear 71. These key people supported other voices to bring about the Grizzly Bear Conservation Initiative, a co-hosted research program supported by Canadian Pacific (CP) and Parks Canada (PC). I led one of the research teams that tackled the problem with additional support from the Natural Science and Engineering Research Council. Together, we had two objectives: understand what causes bear-train collisions, and recommend ways to mitigate that problem.
Former UAlberta Interdisciplinary PhD student Jonathan Backs changes out the batteries on a device that helps warns grizzly bears of oncoming trains. Photo: Colleen St. Clair
A team of students, research associates, and collaborators was supported by dozens of technicians, volunteers, and staff each from CP and PC. PC biologists fitted GPS collars on 26 bears with exceptional care and success. We measured grain deposits and vegetation along the rail, combed through records of past mortality, examined bear hair and scat, studied the locations and movement trajectories of the GPS-collared bears, analyzed stable isotopes and environmental toxins, and compared our field measures to satellite- sourced environmental information.
We found diverse sources of bear-attracting food on or near the rail that included tonnes of grain spilled by hopper cars,[2] several species of palatable plants, both native and introduced, enhanced productivity of buffalo berry (a local staple of bear diets),[3] and train-killed ungulates.[4] A few bears also used the rail extensively as a travel corridor,[5] and some even dug up nearby caches of spilled grain collected by red squirrels.[6] Bear hair provided isotopic evidence of past railway exposure,[7] and grain deposits contained petrochemical pollutants,[8] as well as calories. Decades of meticulous records by CP and PC showed that bears are not alone in their vulnerability; collisions with ten other species of large mammals summed to hundreds of individuals over the past quarter century.[9]
“Mitigation that includes the retrofitted and replaced hopper cars has been highly successful at reducing train mortality for grizzly bears.”
We found limited support for a prevalent hypothesis at the beginning of the project, that vulnerability to train strikes was caused mainly by attraction to grain; actually, more grain was spilled at monitoring sites without past mortality,[10] which was also less likely at locations where the GPS collared bears spent more time on the rail.[11] However, it could be that retrofitting hopper cars, completed just before our study began, vastly reduced spillage and attraction causing mortality. Other historic factors may also have contributed to the sudden appearance of grizzly-train collisions in the year 2000.[12] Interestingly, that was the year when elk mortality on the rail peaked and immediately before a precipitous drop in elk population size.[13] That population decline followed recent recolonization of the Bow Valley by wolves and intensive management to reduce the congregation and habituation of elk in the town site of Banff, likely contributing to rail-caused elk mortality on its margins.
Results from our studies and work by others supported several forms of mitigation. As Bear 71 made clear, animals are much more vulnerable when they are surprised by approaching trains and lack rapid escape routes. PC and CP have worked collaboratively to reduce vegetation near the rail that appears to obscure both visual and acoustic cues. We invented a rail-mounted warning system that works much like crossing signals for people[14] and causes animals to leave the rail several seconds earlier than otherwise,[15] potentially avoiding panicked responses that increase collision likelihood. We also identified the circumstances that best predict mortality among species: train speed, proximity and amount of water, and track curvature.[16] All four factors characterize two relative hotspots of past grizzly bear collisions so future mitigation might target similar locations in this and other landscapes.
“We found limited support for a prevalent hypothesis at the beginning of the project, that vulnerability to train strikes was caused mainly by attraction to grain.”
Correlatively, mitigation that includes the retrofitted and replaced hopper cars has been highly successful at reducing train mortality for grizzly bears. In contrast to the thirteen confirmed mortalities between 2000 and 2011, the year the initiative began,[17] only two confirmed events with three fatalities occurred between 2012 and 2020. Of course, correlation is not the same as causation, and the real reason for the decline could be that the bears themselves have adapted to the rapid changes in their environment that occurred at the turn of the century, one of which was the recent reduction in management-associated mortality for so-called problem bears.[18] We humans are getting better at coexisting with wildlife, even if we have new challenges and still have a lot to learn.
Elk on the rail. Photo: Grizzly Bear Conservation Initiative
From the beginning, I hoped to expand the vision offered by those founding individuals to reduce mortality not only for Alberta’s threatened population of grizzly bears, but for wildlife around the world, where train-caused mortality occurs without enough public interest and economic capacity to address it. I think we have offered lessons that can be used in this service, including the importance of collaborative effort by individuals from so many walks of life. In the ten years since the Grizzly Bear Conservation Initiative was launched, human visits to Banff have increased by twenty-five percent to over four million annually. Wildlife will need all the innovation and assistance we can provide to persist in an increasingly human-dominated world.
AUTHOR
Colleen Cassady St. Clair is a professor of biological sciences at the University of Alberta. She and her students emphasize animal behaviour in their studies of wildlife management and conservation.
References
[1] Bertch, B. & Gibeau, M. Grizzly bear monitoring in and around the Mountain National Parks: Mortalities and bear/human encounters 1980–2009. Parks Canada, 22 (2010).
[2] Gangadharan, A. et al. Grain spilled from moving trains create a substantial wildlife attractant in protected areas. Animal Conservation 20, 391-400, doi:10.1111/acv.12336 (2017).
[3] Pollock, S. Z., Nielsen, S. E. & St Clair, C. C. A railway increases the abundance and accelerates the phenology of bear-attracting plants in a forested, mountain park. Ecosphere 8, e01985, doi:10.1002/ecs2.1985 (2017).
[4] Murray, M. H., Fassina, S., Hopkins, J. B., III, Whittington, J. & St Clair, C. C. Seasonal and individual variation in the use of rail-associated food attractants by grizzly bears (Ursus arctos) in a national park. Plos One 12, e0175658, doi:10.1371/journal. pone.0175658 (2017).
[5] Pollock, S. Z., Whittington, J., Nielsen, S. E. & Clair, C. C. S. Spatiotemporal railway use by grizzly bears in Canada’s Rocky Mountains. Journal of Wildlife Management 83, 1787-1799, doi:10.1002/jwmg.21750 (2019).
[6] Put, J. E., Put, L. & St Clair, C. C. Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears. Nature Conservation-Bulgaria, 1-14, doi:10.3897/natureconservation. 21.12429 (2017).
[7] Hopkins Iii, J. B., Whittington, J., Clevenger, A. P., Sawaya, M. A. & St. Clair, C. C. Stable isotopes reveal rail-associated behavior in a threatened carnivore. Isotopes in environmental and health studies 50, 322-331 (2014).
[8] Pollock, S. Z. & St Clair, C. C. Railway-Associated Attractants as Potential Contaminants for Wildlife. Environmental Management 66, 16-29, doi:10.1007/s00267-020-01277-6 (2020).
[9] St. Clair, C. C., Whittington, J., Forshner, A., Gangadharan, A. & Laskin, D. N. Railway mortality for several mammal species increases with train speed, proximity to water, and track curvature. Scientific Reports 10, 13, doi:10.1038/s41598-020-77321-6 (2020).
[10] St. Clair, C. C. et al. Animal learning may contribute to both problems and solutions for wildlife - train collisions. Philosophical Transactions of the Royal Society B-Biological Sciences 374, 20180050, doi:10.1098/rstb.2018.0050 (2019).
[11] Pollock, S. Z., Whittington, J., Nielsen, S. E. & Clair, C. C. S. Spatiotemporal railway use by grizzly bears in Canada’s Rocky Mountains. Journal of Wildlife Management 83, 1787-1799, doi:10.1002/jwmg.21750 (2019).
[12] St. Clair, C. C. et al. Animal learning may contribute to both problems and solutions for wildlife - train collisions. Philosophical Transactions of the Royal Society B-Biological Sciences 374, 20180050, doi:10.1098/rstb.2018.0050 (2019).
[13] Gilhooly, P., Nielsen, S. E., Whittington, J. & St Clair, C. C. Wildlife mortality on roads and railways following highway mitigation. Ecosphere 10, e02597, doi:10.1002/ecs2.2597 (2019).
[14] Backs, J. A. J., Nychka, J. A. & St Clair, C. C. Warning systems triggered by trains could reduce collisions with wildlife. Ecological Engineering 106, 563-569, doi:10.1016/j.ecoleng. 2017.06024 (2017).
[15] Backs, J. A. J., Nychka, J. A. & St Clair, C. C. Warning systems triggered by trains increase flight-initiation times of wildlife. Transportation Research Part D 87, 102502 (2020).
[16] St. Clair, C. C., Whittington, J., Forshner, A., Gangadharan, A. & Laskin, D. N. Railway mortality for several mammal species increases with train speed, proximity to water, and track curvature. Scientific Reports 10, 13, doi:10.1038/s41598-020-77321-6 (2020).
[17] St. Clair, C. C. et al. Animal learning may contribute to both problems and solutions for wildlife - train collisions. Philosophical Transactions of the Royal Society B-Biological Sciences 374, 20180050, doi:10.1098/rstb.2018.0050 (2019).
[18] St. Clair, C. C. et al. Animal learning may contribute to both problems and solutions for wildlife - train collisions. Philosophical Transactions of the Royal Society B-Biological Sciences 374, 20180050, doi:10.1098/rstb.2018.0050 (2019).