The effects of highway transportation corridors on wildlife: a case study of Banff National Park

Road fragmentation is a concern for wildlife viability in and adjacent to p rotected areas in the Rocky Mountains. Roads create a barrier to wildlife m ovement and have documented demographic effects, including the alteration o f animal communities, the reduction of biological diversity, and the increa sed threat of extinction. Wildlife movement across and adjacent to the Tran s-Canada Highway (TCH) (14,000 annual average daily traffic, AADT) and High way 1A (3000 AADT) was studied in Banff National Park, Alberta. Animal trac ks were observed crossing roadways and on transects adjacent to roads for w olves, cougar, lynx, wolverine, marten, elk, deer, sheep, hare, and red squ irrel relative to road types. Data were analyzed to assess the barrier effe ct and a geographical information system (GIS) was used to identify landsca pe attributes associated with species movement. The TCH was found to be a b arrier to movement for all species, In less perturbed environments, it was observed that movement patterns for the wildlife communities were spatially continuous and that individual species movement was complex. This movement was not observed across the TCH. An interpolation of point data showed sit es of high crossing frequeney within the continuum of crossing points. Thes e sites ranged from 250 to 2000 m in diameter. General predictors for movem ent by aspect were found to be the south, southwest and west facing slopes. Flat slopes, areas of low topographic complexity, and slopes lower than 5 degrees were also effective predictors of animal movements. The data sugges t that maintaining contiguous tracts of habitat with the above attributes f acilitate normal wildlife movement most effectively. Mitigation that approx imates previous patterns can be achieved only by elevating and/or burying e xtensive sections of highway. (C) 2000 Elsevier Science Ltd. All rights res erved.