Attributes of Woodland Caribou Migration Habitat in West-Central British Columbia

Abstract

We examined sites used by 73 caribou located by radio-tracking during spring migration through a forested travel corridor. The physical and botanical characteristics of these sites were described to find what features (if any) distinguished them from the forest at large. Raised and open aspect, sparse tree cover, free-draining soils, and a simple flora with abundant lichens were features common to all the sites, but were lacking in the denser forest around. Scores for these attributes were ordinated by multidimensional scaling of similarities and differences from site to site. Separate searings for (i) terrain features, (ii) tree cover attributes, and (iii) floristic content each yielded a single cluster of points with few outliers and no particular pattern or trend. The inference is that the sites conformed to a single type with limited variation. A profile of the distinguishing characteristics was compiled and then applied to transects through the general migration area by persons unfamiliar with it beforehand. Sites which matched the profile proved easy to identify, even though they comprised only a small proportion of the area. Sites with high scores for the most distinctive attributes had more caribou at the time of radio-tracking.

Feeding site selection by woodland caribou in north-central British Columbia

“…The habitat requirements of the northern woodland caribou ecotype of British Columbia are largely unknown (Harrison & Surgenor, 1996). This ecotype has been the subject of few studies, but is known to inhabit areas of low to moderate snow depths in low elevation forests, and to forage primarily on terrestrial lichens during winter (Hatler, 1986;Cichowski, 1993;Lance & Mills, 1996;Wood, 1996). Most caribou research in British Columbia has focused on the mountain caribou ecotype which spends little time in low elevation areas during the winter, but forages instead on arboreal lichens at high elevations (Servheen & Lyon, 1989;Terry, 1994).…”

A multi-scale behavioural approach to understanding the movements of woodland caribou.

“…Across the range of the Wolverine herd, canopy closure did not affect the selection of cratering sites. In contrast, Cichowski (1993) and Lance and Mills (1996) found that cratering occurred most often in forested areas with more open canopies. In both cases, however, there was an interaction with the presence of terrestrial lichens suggesting that open canopy stands were more productive.…”

“…Caribou reduce the risk of predation by taking refuge at less-accessible locations, such as high alpine areas or islands (Bergerud et al 1984, Bergerud 1985, Bergerud and Page 1987, Gumming and Beange 1987, Seip 1992, James 1999. Specific movement corridors across the landscape also have been recognised (Hatler 1986, Lance andMills 1996). reported that caribou of the Tweedsmuir-Entiako herd in westcentral British Columbia were associated with old forest on sites of poor productivity and with wetland mosaics while transiting between winter and summer ranges.…”

“…In both cases, however, there was an interaction with the presence of terrestrial lichens suggesting that open canopy stands were more productive. Our analysis used a moosehom coverscope as opposed to a visual estimate of canopy closure (Cichowski 1993, Lance andMills 1996). The latter estimates closure of a much larger portion of the canopy (i.e., scale of the stand) than the coverscope (i.e., scale of the feeding site).…”

“…This ecotype has been the subject of few studies, but is known to inhabit areas of low to moderate snow depths in lowelevation forests, and to forage primarily on terrestrial lichens during winter (Hatler 1986, Cichowski 1993, Lance and Mills 1996, Wood 1996. Most caribou research in British…”