The Banff story has had international ramifications. Since 1980, Parks Canada has been in the process of four-laning
(twinning as they call it) the Trans-Canada Highway. The Trans-Canada Highway is the major east–west corridor for motor vehicles across Canada and traffic levels continue to increase. In addition, Banff National Park is one of the gems of the Canadian park system, with nearly 4 million people entering the park each year (Leeson 1996). By the summer of 1992, the levels of traffic had so deteriorated that passing was impossible, maximum speeds were below 80 km/h (49.71 mi/h), and time delays exceeded 75%. With environmental protection as a paramount priority, Parks Canada developed a phased approach to addressing environmental concerns.
In the first two phases, approximately 16% of the budget to twin 31 km (19.25 mi) of the highway was de- voted to environmental features. These features included 10 wildlife crossings each with a 2.4-m (8-ft) high fence that included one-way gates that allowed for animals caught between the fences to exit the roadway corridor. In the third phase, approximately 30% of the budget was de- voted to environmental features. In this 18 km (11.18 mi) section of the highway, two overpasses (Figure 25) and 13 underpasses were constructed and the 2.4-m (8-ft) high fence was continued. Figure 26 depicts several of the un- derpasses used in Banff National Park. Parks Canada con- structed a combination of pipe culverts, box culverts, and open-span bridges of varying size and design. The two overpasses built for this section are approximately 50 m (164 ft) wide.
FIGURE 25 Large overpass used by wildlife in Banff National Park, Alberta.
FIGURE 26 Underpass in Banff National Park, Alberta.
There remains one more phase to complete the twinning through Banff National Park, which will involve 30 km (18.64 mi) of highway. This final phase awaits the budget and the results of research to help Parks Canada make de- cisions about what needs to be done. Wisely, Parks Canada began an extensive research effort to scientifically docu- ment the effectiveness of the existing 23 wildlife under- passes and 2 overpasses on approximately 49 km (30.45 mi) of the Trans-Canada Highway. This was an important decision because this is one of the longest stretches of highway in the world with features undertaken to provide wildlife connectivity.
The Banff research on road effects on wildlife began in November 1996. Therefore, recent published results repre- sent nearly 5 years of research effort on the effectiveness of mitigation measures and incidence of road-related mor- tality in Banff National Park. To describe the unprece- dented success of this research, the following is a modified summary of results taken from the most recent progress re- port (Clevenger 2001):
• There have been a total of 26,279 through-passes by wildlife at the 11 (phases I and II) underpasses since November 1996. Elk were the most frequently detected species at the crossing structures, followed by deer, coyotes, and sheep. Among large carnivores, wolves used the structures 1,190 times, cougars 517 times, black bears 380 times, and grizzly bears 14 times. • There have been 5,515 passages by wildlife at the 13
(phase IIIA) crossing structures since November 1997. Among large carnivores, cougars used the structures 149 times, black bears 127 times, wolves 100 times, and grizzly bears 16 times.
• On average deer used the phase IIIA wildlife over- passes 12 times more than the IIIA underpasses, whereas elk used the overpasses 3 times more than underpasses. Since June 2000, moose used the phase IIIA crossing structures seven times (six times on over- passes and once on an underpass). All carnivores except cougars have used both overpasses. Since 2000, wolves have used the two overpasses as a group (i.e., be- tween two and seven individuals) five times.
• In the 50 months of monitoring more than 31,794 in- dividual wildlife passes have been detected at the 24 crossing structures.
• There was a general pattern of increased use at phase IIIA overpasses for all large carnivore species during the first 3 years of monitoring. Increased annual pas- sage frequencies were particularly dramatic in grizzly bears, wolves, and cougars during the third year of monitoring (i.e., 4 to 25 times greater than the aver- age use during the first 2 years).
• Cougars use of the underpasses has gone from rela- tively low levels and seasonal use to moderate, year- round use. Wolf use of underpasses has varied
geographically by pack, depending on wolf pack size and adaptation to underpasses. Elk use of underpasses has not changed geographically, but the frequency of use decreased substantially in 2000. Deer use of un- derpasses has not changed geographically and the amount of use has increased slightly each of the suc- cessive 4 years.
• Researchers found that for many small- and medium- sized mammals drainage culverts can mitigate harm- ful effects of busy transportation corridors and pro- vide a vital habitat linkage. To maximize across road connectivity for meso-fauna, future road construction schemes should include frequently spaced culverts of mixed-size classes and have abundant vegetative cover present near culvert entrances.
• Since January 1997, a total of 237 animals were re- ported killed on the Trans-Canada Highway in Banff, Yoho, and Kootenay national parks; 143 (60%) were ungulates and 94 (40%) were carnivores. Carnivore mortalities consisted of coyotes (56%), black bears (28%), wolves (11%), and cougars (4%).
• A review of road mortality data of large carnivores in Banff National Park from 1981 to the present showed that 48 large carnivores (black bear, wolf, cougar, and wolverine) have been killed. For wolves (80% of 20), black bears (52% of 23), and all large carnivores combined (65% of 48) mortality was highest on un- mitigated, unfenced Trans-Canada Highway.
• Four years of road-kill surveys covered a total of 49 994 km (31,064.83 mi). A total of 824 animals (60 identified species) were collected from 827 different road sites. These included 354 mammals (23 species), 312 birds (35 species), and 158 amphibians (2 spe- cies). Mammals accounted for 43% of the kills, birds 38%, and amphibians 19%. Along the Trans-Canada Highway birds were the most common road-killed taxa, accounting for 43% of all mortality, mammals were second accounting for 37%, and amphibians third with 20%. On the Bow Valley Parkway, mam- mals were the most frequently killed at 56%, fol- lowed by birds at 28%, and amphibians 16%. Road- kill indices were highest for mammals on the Bow Valley Parkway, with 8.3 roadkills/1000 km (621.37 mi) sampled as opposed to 6.2 roadkills/1000 km on the Trans-Canada Highway.
• Researchers developed three different but spatially explicit habitat models to identify linkage areas across transportation corridors. One model was based on empirical data and the other two models were based on expert information developed in a multi- criteria, decision-making process. We used the em- pirical model as a yardstick to measure the accuracy of the expert-based models. Our tests showed the ex- pert literature-based model most closely approxi- mated the empirical model, both in the results of sta- tistical tests and the description of the cross-highway
habitat linkages. Our empirical and expert models represent useful tools for resource and transportation planners charged with determining the location of mitigation passages for wildlife when baseline infor- mation is lacking and when time constraints do not allow for preconstruction data collection.
• Researchers developed a GIS approach to modeling animal movements across transportation corridors. The work consisted of three steps: (1) the creation of high-resolution, regional-habitat suitability models for four large mammal species, black bear, grizzly bear, moose, and elk; (2) developing a regional-scale movement component to the models; and (3) nested within step 2, constructing local-scale movement models of high spatial resolution. Recommendations regarding the location of potential mitigation based on the intersection of simulated pathways with trans- portation corridors and other human infrastructure are the result of this exercise. The full results from this work are being prepared as a separate report to Parks Canada in May 2001.
The Banff projects are some of the most successful for wildlife connectivity. The long-term research of the effec- tiveness of the measures taken to provide connectivity also has world-wide importance. Information on the progress of wildlife activities in Banff National Park can be obtained at www.hsctch-twinning.ca.