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) http://repositories.cdlib.org/jmie/roadeco/Dodd2005a

S.C. Trombulak, C.A. Frissell. “Review of Ecological Effects of Roads on Terrestrial and Aquatic Communities” Conservation Biology V 14 no.1 (2000) 18-30

USDA “American Elk (Cervus elaphus)” Fish and Wildlife Habitat Management Leaflet no. 11 (1999)