Historical-ecological evaluation of the long-term distribution of woodland caribou and moose in central British Columbia

Throughout the 1800s and the 1900s, woodland caribou disappeared from much of the central and southern portions of British Columbia, Canada. Conversely, moose populations expanded during the 1900s and rapidly colonized forested areas formerly occupied by caribou. Although the general trend in range recession and expansion is documented, the processes, timing, and spatial extent of overlap between these two ungulates are uncertain. Such details have implications for our understanding of the ecology of these species and the conservation of woodland caribou. Using historical-ecological methods, we documented the distribution and abundance of caribou and moose over a 150-year period. Also, we evaluated three general sources of evidence for documenting long-term changes in the distribution of hunted or trapped fauna: (1) semi-structured interviews with Aboriginal and non-aboriginal residents; (2) journals of the Hudson's Bay Company (HBC); and (3) primary written sources. The findings of this study suggested that caribou were relatively wide-spread throughout the study area until the late 1800s when their distribution began to decline. The first recorded sighting of moose in the study area was 1832, although consensus among sources suggested that moose expanded into the area at the end of the 1800s becoming abundant in the 1920s and 1930s. Proposed causes of decline of caribou included climatic change during the 1800s and habitat loss, hunting, and altered predator-prey dynamics through the early 1900s. Our analysis of three sources of historical information and knowledge confirmed the value of Local and Traditional Ecological Knowledge in documenting and explaining long-term historical distribution of hunted species. Alternatively, HBC journals and other written sources provided good temporal specificity, but few recorded locations of caribou or moose. Documenting changes in the long-term distribution of both species can enlighten conservation planning for woodland caribou.