Roads and other developments have been shown to be particularly problematic for Woodland Caribou (rangifer tarandus caribou). This means they can be considered an umbrella species - if this species is thriving, then the rest of the ecosystem can be assumed to be healthy. (Hummel and Mayes 2007¹).

Martin Kienzler, Government of Yukon

Woodland Caribou are federally listed and declining throughout their range in Canada because of the cumulative impacts of infrastructure development (J. Poifus 2010²). Restoring caribou habitat has not been effective (Sinclair et al 2006³) - a more effective approach is to conserve areas where human impact is low (Sanderson at al, 2007⁴).

Additional potential impacts to caribou from development include: barriers to movement, habitat fragmentation, increased access, and direct and indirect habitat loss during calving and rutting periods when caribou may have heightened sensitivity to disturbance. (Polfus 2010)

What accounts for this widespread and growing decline across Canada? In simplest terms, woodland caribou live part or all of the year in large tracts of old forest with abundant slow growing lichens and relatively little use by other hoofed mammals. As these forest tracts are reduced in size, made more accessible to predators and hunters, and converted to younger stands attractive to other hoofed mammals, their capacity to support caribou erodes.

Southern Mountain and Boreal Caribou are listed under Canada's Species at Risk Act (SARA) as threatened due to habitat destruction caused by roads, mines, oil, gas and forestry extraction (Apps and McLellan 2006). Northern Mountain Caribou (including the Bonnet Plume and Hart Herds in the Peel watershed), are less impacted, however impacts such as hunter overharvest, habitat loss and fragmentation from forestry and energy development, human-induced changes to predator-prey communities, and proliferation of road and snowmobile networks have, to varying degrees, contributed to population declines. These declines prompted federal managers to list Northern Mountain Woodland Caribou as a species of special concern under SARA in 2004. The indirect effects of habitat loss from particular developments may be individually less serious, but their cumulative impact has the potential to significantly affect caribou over time (Scott 2007).

Caribou avoidance of human developments varies between scales, seasons, and development types (Poifus 2010). Polfus' caribou study near Atlin in Northern BC found that caribou tend to avoid high use roads by 2 km and low use roads by 1 km. Caribou avoided the town site by 9 km in winter and 3 km in summer. There was low avoidance of mines (250 m) and no avoidance of cabins and hunting camps in winter, while in summer the buffer around mines was 2 km and the buffer around cabins and hunting camps was 1.5 km.

In Norway Nellemann et al. (2001⁵, 2003⁶) found that wild reindeer avoid areas within 5 km of development and reindeer densities near infrastructure declined by up to 92% in winter. In Canada, Dyer et al. (2001)⁷ studied the distribution of woodland caribou in association with human infrastructure in the Athabasca oil sands of northern Alberta. Their results established that caribou avoided areas within 250 m of roads and seismic lines and within 1,000 m of oil well sites. Avoidance was greatest during winter. Woodland caribou have also been shown to avoid mining activity by 4 km in winter (Weir et al. 2007). Johnson et al. (2005)⁸ found that the effects of human development could be as far reaching as 33 km.

These impacts will likely be exacerbated by a warming climate. Changes in date of snowmelt, plant and insect phenology, species distributions, extreme weather events, and ecosystem alterations due to tree-line advance and loss of alpine environments may challenge the ability of caribou to adapt to changing environments. Post et al. (2008)⁹ has found that warming increased the variability of plant phenology in Greenland and impaired the ability of caribou to forage selectively, resulting in effects on productivity. These and other unforeseen consequences of climate change emphasize the need to minimize levels of human disturbance within high quality caribou habitat.

The Little Rancheria Herd Yukon is a woodland herd near Watson Lake. Recommendations for the conservation of their winter range include: (Adamczewski, Florkiewicz & Loewen, 2003¹⁰):

• withdraw the core winter range from further logging or development,
• establish a connected reserve network of high-quality habitat in the extended range and migration zone, and
• establish maximum development footprint values of 30% in the extended range and 25% in the migration zone.

1. Hummel, M., and J. C. Ray. 2008. Caribou and the north: a shared future. Dundurn Press, Toronto.
2. Polfus, Jean L., M.S., May 2010 Wildlife Biology, assessing cumulative human impacts on northern woodland caribou with traditional ecological knowledge and resource selection functions
3. Sinclair, A. R. E., J. M. Fryxell, and G. Caughley. 2006. Wildlife ecology, conservation and management. Second edition. Blackwell Publishing Ltd., Malden, MA.
4. Sanderson, E. W., M. Jaiteh, M. A. Levy, K. H. Redford, A. V. Wannebo, and G.Woolmer. 2002. The human footprint and the last of the wild. Bioscience 52:891904.
5. Nellemann, C., I. Vistnes, P. Jordhoy, and O. Strand. 2001. Winter distribution of wild reindeer in relation to power lines, roads and resorts. Biological Conservation 101:351-360.
6. Nellemann, C., I. Vistnes, P. Jordhoy, O. Strand, and A. Newton. 2003. Progressive impact of piecemeal infrastructure development on wild reindeer. Biological Conservation 113:307-317.
7. Dyer, S. J., J. P. O'Neill, S. M. Wasel, and S. Boutin. 2001. Avoidance of industrial development by woodland caribou. Journal of Wildlife Management 65:531-542. And 2002. Quantifying barrier effects of roads and seismic lines on movements of female woodland caribou in northeastern Alberta. Canadian Journal of Zoology 80:839-845.
8. Johnson, C. J., M. S. Boyce, R. L. Case, H. D. Cluff, R. J. Gau, A. Gunn, and R. Mulders. 2005. Cumulative effects of human developments on arctic wildlife. Wildlife Monographs:1-36.
9. Post, E., C. Pedersen, C. C. Wilmers, and M. C. Forchhammer. 2008. Warming, plant phenology and the spatial dimension of trophic mismatch for large herbivores. Proceedings of the Royal Society B-Biological Sciences 275:2005-2013.
10. Rancheria caribou habitat management, Adamczewski, Florkiewicz & Loewen, 2003