2. General Question: what can we do about
habitat fragmentation?
A) Habitat fragmentation
B) Habitat avoidance
C) Habitat mitigation using wildlife crossing structures (FOCUS OF PRESENTATION)
D) Habitat compensation by creation of replacement habitat nearby
11. STUDY#1: Wildlife crossing structures
promote 'gene flow' in Banff bears
The crossings – there are currently 44 in all
– form the most extensive system of wildlife
crossing structures on the planet
12. A sow grizzly and a cub are seen on a wildlife
overpass above the Trans-Canada Highway in
Banff National Park
A grizzly bear passes through a hair-snagging
system used to study the DNA of bears using a
wildlife overpass above the Trans-Canada Highway
in Banff National Park
Bear using a wildlife underpass to avoid the
TCH
These wildlife crossing structures cost millions of dollars
and this is one of the first studies that has shown that
they are doing what they are intended to do
14. Why did the flying squirrels cross the
road?
Prior to the installation of the crossing structures,
flying squirrels would not cross the Skyway. In two
years of radio-tracking and trapping, not one
squirrel was observed to have crossed the Cherohala
Skyway.
15. Summary
Human disturbance has caused habitat fragmentation
Fragmentation increases the chance for species extinction by:
Increasing inbreeding
Loss of genetic diversity decreasing fitness
Reducing ability of populations to adapt to change
Research shows that crossing structures do what they are intended to do
Wildlife crossing structures mitigate the effects of fragmentation by:
Promoting gene flow (migration)
Increasing genetic diversity increasing fitness
Preserving wildlife welfare
19. References
Gubbi, S. (2011). Safe passages: Highways, wildlife, and habitat connectivity edited by Jon P. Beckmann, Anthony P.
Clevenger, Marcel P. Huijser & Jodi A. Hilty (2010), xix + 396 pp., Island Press, Washington, DC, USA. Chapter 7.
Clevenger, A., & Sawaya, M. (2010). Piloting a non-invasive genetic sampling method for evaluating population-level benefits
of wildlife crossing structures. Ecology and Society, 15(1), 7-7.
Ford, T. A., Clevenger, A., & Bennett, A. (2009). Comparison of methods of monitoring wildlife-crossing structures on
highways. Journal of Wildlife Management. doi: http://dx.doi.org.proxy.lib.sfu.ca/10.2193/2008-387
Kelly, C.A., Diggins, C.A., Lawrence, A.J. (2013). Crossing structures reconnect federally endangered flying squirrel
populations divided for 20 years by road barrier. Wildlife Society Bulletin. 37(2): 375-379
Parks Canada. (2014). Banff national park: wildlife crossing structures and research. Retrieved from:
http://www.pc.gc.ca/eng/pn-np/ab/banff/plan/transport/tch-rtc/passages-crossings.aspx
Sawaya, M. A., Clevenger, A. P., & Kalinowski, S. T. (2013). Demographic connectivity for ursid populations at wildlife crossing
structures in banff national park. Conservation Biology, 27(4), 721-730.
Sawaya, M. A., Kalinowski, S. T., & Clevenger, A. P. (2014). Genetic connectivity for two bear species at wildlife crossing
structures in banff national park. Proceedings. Biological Sciences / the Royal Society, 281
Makrakis, S., Castro-Santos, T., Makrakis, M., Wagner, R., & Adames, M. (2012). Culverts in paved roads as suitable passages
for neotropical fish species. Neotropical Ichthyology, 10(4), 763-770.
Downs, J., Horner, M., Loraamm, R., Anderson, J., Kim, H., & Onorato, D. (2014). Strategically locating wildlife crossing
structures for florida panthers using maximal covering approaches. Transactions in GIS, 18(1), 46-65.
