PLoS One. 2015 Sep 8;10(9):e0136933. doi: 10.1371/journal.pone.0136933. eCollection 2015.
- 1Alberta
Biodiversity Monitoring Institute, Department of Biological Sciences,
University of Alberta, Edmonton, Alberta, Canada; Stantec, Environmental
Services, Sidney, British Columbia, Canada.
- 2Alberta Biodiversity Monitoring Institute, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
- 3Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Abstract
In-situ
oil sands development (ISD) involves a network of facilities, wells,
roads and pipelines to extract and transport subsurface bitumen. This
technology is rapidly expanding and there is uncertainty whether ISDs
restrict animal movement, leading to increased extinction probabilities
for some wide-ranging species. Here we test for effects of simulated
future (i.e., 50 years from now) and current ISDs on simulated movements
of woodland caribou
(Rangifer tarandus), a threatened species across North America. In
simulations of future scenarios, we varied the spacing and permeability
of ISDs and the presence/absence of protected areas. Permeability was
measured as the number of times simulated caribou crossed ISDs with different levels of modelled permeability. We estimated the effects of these factors on caribou
step length and annual home range size, key metrics of small and large
spatiotemporal scales of movement, respectively. Current caribou crossings of above-ground pipeline features of ISDs were measured using camera traps and compared to expected caribou crossing rates based on present-day caribou
movement simulations. Current crossing rates were evaluated within the
context of predicted future crossing success rates necessary to maintain
caribou step lengths and home ranges. With few exceptions, permeability across ISDs was the main factor affecting caribou
movement, more so than spacing between developments or the presence of
protected areas. However, minimal permeability (crossing rates of c. 15%
to 60%, relative to an undisturbed site was needed to maintain existing
home range size and step lengths. The effect of permeability on home
range size and step length was non-linear, suggesting that small
increases in permeability would provide a disproportionately greater
benefit to caribou
movement. Our predictions demonstrate that maintaining permeability
across ISDs is more important than spacing between leases or including
protected areas, and thus provides clear direction for mitigation
efforts for features that will exist on the landscape for decades to
come.
