PAGE 4 IMPROVING CONNECTIVITY ACROSS BANFF’S TRANS-CANADA HIGHWAY
EXECUTIVE SUMMARY Parks Canada has begun a process <strong>to</strong> upgrade the remaining 35-kilometre section of the <strong>Trans</strong>-Canada Highway (TCH) through Banff National Park, from Castle Junction <strong>to</strong> the western park boundary at the Alberta-British Columbia border (known as Phase IIIB). As part of the proposal, the project aims <strong>to</strong> provide adequate mitigations <strong>to</strong> “reduce habitat fragmentation” caused by the THC. However, there is some question whether the proposed twinning project can be implemented without significantly impairing the surrounding ecosystem. According <strong>to</strong> the Screening Report for the <strong>Trans</strong>-Canada Highway Twinning Project, Phase IIIB, Banff National Park, the proposed widening and fencing of the highway will “adversely affect wildlife’s ability <strong>to</strong> move <strong>across</strong> the landscape” (Golder and Associates 2004). The question remains: Can the proposed mitigations be improved <strong>to</strong> better meet the project’s habitat <strong>connectivity</strong> goal? This paper was developed <strong>to</strong> help answer that question, serving as an independent, scientifically rigorous analysis of wildlife movement data collected in the Banff-Bow Valley. It provides important information about where mitigation might be most effectively placed and how much might be constructed <strong>to</strong> reasonably achieve the goal <strong>to</strong> reduce habitat fragmentation along Phase IIIB of the TCH. Based on the best (in some cases only) available empirical data on four focal carnivores (marten, lynx, cougar and wolf) and using scientifically supported, peer-reviewed analytical techniques, we determined the probability of occurrence for marten, lynx, cougar and wolf within 500 metres of Phase IIIB. Once mapped, these models identified the best potential linkage zones for each species, and for groups of species. The results indicated that some of the proposed crossing structures are in less than ideal locations, and that the sum <strong>to</strong>tal of the mitigation (including fencing) only mitigates a small percentage of the linkage zones that are available for wildlife <strong>to</strong> use if adequate crossing structures are built. If all proposed mitigation is constructed as the TCH is twinned, a <strong>to</strong>tal of 3147 metres (9.0 percent) of habitat will be maintained for linkages. Of that, drainages (for marten) are the largest contribu<strong>to</strong>r <strong>to</strong> <strong>connectivity</strong> (7.5 percent) followed by primary structures (1.3 percent) for multi-species (if placed in optimal locations); secondary and tertiary structures capture less than 0.1 percent of <strong>to</strong>tal highway length (35 kilometres). On the other hand, <strong>to</strong> mitigate the <strong>to</strong>p 20 percent of habitat as linkage zones for each species would require a minimum of 2.7 kilometres, and a maximum 6.7 kilometres of mitigation, depending on the species considered. As a result, the report proposes a number of improvements <strong>to</strong> better reduce habitat fragmentation caused by the TCH. Building structures in better locations, widening currently proposed structures, and building additional structures would provide an additional 1900 meters of high quality linkage zones. If placed in the optimal locations for each species, habitat <strong>connectivity</strong> would increase from 9.27 <strong>to</strong> 32.75 percent for wolves, 47.48 <strong>to</strong> 67.28 percent for marten, 10.78 <strong>to</strong> 38.11 percent for lynx, and from 19.33 <strong>to</strong> 68.32 percent for cougar. While the increased amount of habitat <strong>connectivity</strong> provided by the additional structures would not mitigate the <strong>to</strong>p 20 percent of habitat for each species, it would be a marked improvement over the current proposal. IMPROVING CONNECTIVITY ACROSS BANFF’S TRANS-CANADA HIGHWAY PAGE 5