Evaluating functional recovery of habitat for threatened woodland caribou

摘要

Habitat restoration is a core element for the recovery of many declining species. In western Canada, habitat restoration for the recovery of woodland caribou is focused on linear features ( LF s) created by oil and gas exploration. At present, the only established criterion for LF restoration is when vegetation structure on LF s is similar to surrounding vegetation. Human‐mediated habitat alteration impacts caribou population dynamics by increasing caribou predation rates in two ways: increasing alternate prey populations leading to higher predator numbers and increasing predator hunting efficiency. Linear features increase the movement rates—and may thus increase hunting efficiency—of wolves, a primary predator of caribou and a main hypothesized mechanism for population declines. One approach to determine LF recovery is to identify potential thresholds in the characteristics of regenerating LF s where efficiencies in wolf movement rates are no longer evident. We examined how vegetation affects wolf selection of, and movement on, LF s in northeastern Alberta using five‐minute Global Positioning System locations from 20 wolves. Wolves selected LF s with shorter vegetation and traveled faster on LF s with shorter, sparser vegetation and increased vegetation variability. Travel speeds were reduced by 1.5–1.7?km/h when vegetation exceeded heights of 0.50?m, but at least 30% of a LF required vegetation exceeding 4.1?m to slow movement rates to those traveled while in forest. Policy implications: Most of the movement efficiency afforded to wolves by LF s is mediated when vegetation exceeds 0.50?m, and therefore, active restoration could be focused in areas that have not met this value. Rather than treating this value as a clear threshold equating to functional recovery, multiple metrics across trophic levels must also be evaluated to assess population recovery for caribou.