Habitat loss accelerates for the endangered woodland caribou in western Canada

Abstract

Habitat loss is often the ultimate cause of species endangerment and is also a leading factor inhibiting species recovery. For this reason, species‐at‐risk legislation, policies and plans typically focus on habitat conservation and restoration as mechanisms for recovery. To assess the effectiveness of these instruments in decelerating habitat loss, we evaluated spatiotemporal habitat changes for an iconic endangered species, woodland caribou (Rangifer tarandus caribou). We quantified changes in forest cover, a key proxy of caribou habitat, for all caribou subpopulations in Alberta and British Columbia, Canada. Despite efforts under federal and provincial recovery plans, and requirements listed under Canada's Species at Risk Act, caribou subpopulations lost twice as much habitat as they gained during a 12‐year period (2000–2012). Drivers of habitat loss varied by ecotype, with Boreal and Northern Mountain caribou affected most by forest fire and Southern Mountain caribou affected more by forest harvest. Our case study emphasizes critical gaps between recovery planning and habitat management actions, which are a core expectation under most species‐at‐risk legislation. Loss of caribou habitat from 2000 to 2018 has accelerated. Linear features within caribou ranges have also increased over time, particularly seismic lines within Boreal caribou ranges, and we estimated that only 5% of seismic lines have functionally regenerated. Our findings support the idea that short‐term recovery actions such as predator reductions and translocations will likely just delay caribou extinction in the absence of well‐considered habitat management. Given the magnitude of ongoing habitat change, it is clear that unless the cumulative impacts of land‐uses are effectively addressed through planning and management actions that consider anthropogenic and natural disturbances, we will fail to achieve self‐sustaining woodland caribou populations across much of North America.

An inconvenient misconception: Climate change is not the principal driver of biodiversity loss

“…Instead, conservation biologists try to tackle present‐day problems threatening populations. Put bluntly, why worry about future melting permafrost if woodland caribou Rangifer tarandus population size is declining due to timber harvesting removing vital habitat (Nagy‐Reis et al., 2021), or worry about the genetic recovery of future black rhinoceros Diceros bicornis populations when poaching reduced their global population by 95% in three decades (Berger, 1994). Far too many species will count themselves lucky to run the gamut of climate change if they manage to survive more urgent and direct impacts on their viability.…”

Linking woodland caribou abundance to forestry disturbance in southern British Columbia, Canada

“…We defined the historical forestry disturbance‐caribou abundance relationship of SGSMC using best available abundance data and a simulation model to estimate spatial‐temporal timber harvest and road development. This novel approach is useful for filling disturbance data gaps (specifically, the timing of haul road development) and provides an alternative to using satellite imagery (Johnson et al 2020, Nagy‐Reis et al 2021). Using our approach, we reject our first hypothesis that caribou abundance is most negatively related to forestry disturbances in core habitat.…”

“…The southern group of the southern mountain population of woodland caribou (SGSMC; Environment Canada 2014) is an ecologically distinct group that has experienced an estimated 50% loss in habitat and several subpopulation extirpations (Wittmer et al 2010, Festa-Bianchet et al 2011. Habitat management to conserve these caribou has largely prioritized protection of areas occupied by caribou (i.e., core habitat); however, there is increasing evidence that these efforts may be insufficient to support stable caribou populations (Wittmer et al 2007(Wittmer et al , 2010Nagy-Reis et al 2021). Apps et al (2013) concluded that habitat conditions outside of core southern mountain population habitats can drive numerical and functional predator responses, suggesting that habitat management strategies are also needed for matrix habitats (i.e., habitats adjacent to core habitats).…”

Efficacy and ethics of intensive predator management to save endangered caribou

“…By the time managers turn to predator reduction as a means to reverse the decline of caribou populations, multiple warning signals have already flashed. Even with mounting empirical evidence that confirms a relationship between habitat loss and population decline, industrial disturbance has accelerated over the past several decades since caribou declines were first documented (Environment Canada, 2012;Johnson et al, 2015Johnson et al, , 2020Nagy-Reis et al, 2021;Rempel et al, 2021;Rudolph et al, 2017). Governments have relied on piecemeal mitigation of impacts, rather than limitation of the industrial footprint, long after caribou were legally recognized as Threatened or Endangered.…”