PARENT SESSION
Oral Session #39: Conservation: Landscapes and Reserve Design.
Presiding: D. Peters
Tuesday, August 6. 1:00 PM to 4:45 PM. Graham Meeting Room, TCC.
Impacts of spatial and temporal heterogeneity on evaluating the efficacy of highway crossing structures in Banff National Park, Canada.
Waltho, Nigel*,1, Clevenger, Tony2, 1 York University, Toronto, ON, Canada2 Parks Canada, Banff, AB, Canada
ABSTRACT- Studies assessing wildlife crossing structure efficacy often lead to spurious results because of their failure to address masking effects of confounding variables. Confounding variables include variation in density of crossing structures within the habitat template, equality of species perceived access to each crossing structure, and seasonal variation in the habitat mosaic. We investigated these issues using data obtained from systematic, year-round monitoring of 13 wildlife crossing structures (underpasses and overpasses) 34 months post-construction. First, we standardized against the confounding variables by developing species-specific, crossing structure performance indices (=observed through passage usage/expected through passage usage) for wide-ranging large carnivores and their prey species in Banff National Park, Alberta. Second, we used non-linear regression analysis to ascertain how 13 crossing structure variables encompassing structural, landscape, and human activity attributes best correlate to the performance indices. Our results suggest that structural attributes best correlated to performance indices for both large predator and prey species, while landscape and human-related factors were of secondary importance. Our findings underscore the importance of (a) integrating temporal and spatial variability as a priori when addressing wildlife crossing structure efficacy, and (b) species respond differently to crossing structure features - thus mitigation planning in a multiple-species ecosystem is likely to be a challenging endeavour.
KEY WORDS: wildlife corridors, roads, crossing structures, large mammals