Winter Ecology – Spring 2008 Mountain Research Station – University of Colorado, Boulder David Rosengarten

 Mortality from construction and collisions  Habitat fractionation  Modified animal behavior  Exotic species introduction  Restriction of wildlife movement  Reduction of gene flow, biodiversity

 GPS  Video  Tracks  Collisions

Seasonal differences in crossing frequencies demonstrate winter effect on mammals A different study observed this trend as well in elk and deer, observing 3077 crossings in the summer and only 494 in winter. (Clevenger 2004) Graph of crossing elk/approaching elk by month (Dodd 2007)

Elk  Season  Tolerance  Gender  Nutrients Human  Traffic  Weekday  Fences  Crossing structures There is a lot of interaction between and within these two sets of factors

Placement: Habitat quality has shown a relation to preferred crossing areas Dimensions: The design of a structure will determine what animals are willing/able to use it Limitations: Requirements of different species require high variability in crossing structure design

 Although a severe ecological barrier, roads are crossed by mammals due to larger forcings  Seasonality has a large influence on ungulate movement and sensitivity to roads  Crossing structures can mitigate this effect but much more work needs to be done to determine the most effective methods

 S.M. Alexander, N.M. Waters. “The effects of highway transportation corridors on wildlife: a case study of Banff National Park” Transportation Research Part C 8 (2000) 307±320  A.P. Clevenger, N. Waltho. “ Performance indices to identify attributes of highway crossing structures facilitating movement of large mammals” Biological Conservation 121 (2005) 453–464  N.L. Dodd, J.W. Gagnon, A.L. Manzo, R.E. Schweinsburg. “Video Surveillance to Assess Highway Underpass Use by Elk in Arizona” JOURNAL OF WILDLIFE MANAGEMENT 71-2 (2007) 637–645  N.L.Dodd, J.W. Gagnon, S. Boe, E.E. Schweinsburg. “Characteristics of elk-vehicle collisions and comparison to GPS-determined highway crossing patterns” (2005)  S.C. Trombulak, C.A. Frissell. “Review of Ecological Effects of Roads on Terrestrial and Aquatic Communities” Conservation Biology V 14 no.1 (2000)  USDA “ American Elk ( Cervus elaphus)” Fish and Wildlife Habitat Management Leaflet no. 11 (1999)