Demographic responses of nearly extirpated endangered mountain caribou to recovery actions in Central British Columbia

Abstract

Recovering endangered species is a difficult and often controversial task that challenges status quo land uses. Southern Mountain caribou are a threatened ecotype of caribou that historically ranged in southwestern Canada and northwestern USA and epitomize the tension between resource extraction, biodiversity conservation, and Indigenous Peoples' treaty rights. Human-induced habitat alteration is considered the ultimate cause of caribou population declines, whereby an increased abundance of primary prey-such as moose and deer-elevates predator populations and creates unsustainable caribou mortality. Here we focus on the Klinse-Za and Quintette subpopulations, part of the endangered Central Group of Southern Mountain caribou in British Columbia. These subpopulations were trending toward immediate extirpation until a collaborative group initiated recovery by implementing two short-term recovery actions. We test the effectiveness of these recovery actionsmaternity penning of adult females and their calves, and the reduction of a primary predator, wolves-in increasing vital rates and population growth.Klinse-Za received both recovery actions, whereas Quintette only received wolf reductions, providing an opportunity to test efficacy between recovery actions. Between 1995 and 2021, we followed 162 collared female caribou for 414 animal-years to estimate survival and used aerial counts to estimate population abundance and calf recruitment. We combined these data in an integrated population model to estimate female population growth, total population abundance, and recovery action effectiveness. Results suggest that the subpopulations were declining rapidly (λ = 0.90-0.93) before interventions and would have been functionally extirpated (<10 animals) within 10-15 years. Wolf reduction increased population growth rates by ~0.12 for each subpopulation.Wolf reduction halted the decline of Quintette caribou and allowed them to increase (λ = 1.05), but alone would have only stabilized the Klinse-Za

Indigenous‐led conservation: Pathways to recovery for the nearly extirpatedKlinse‐Zamountain caribou

“…In contrast, other southern mountain subpopulations reviewed in Serrouya et al (2019) declined during a similar time at an average rate of 14% per year (range À35% to À3%) when no recovery actions were taken and declined at 8% (range À36% to +13%) despite a variety of management actions applied such as wolf reductions in isolation, translocations, and moose reductions. In McNay et al (2022), we estimate that the increased population growth of the Klinse-Za subpopulation can be attributed as approximately onethird due to maternal penning and two-thirds due to wolf reduction. The increases garnered in the Klinse-Za have put the Nations on a path towards their goal of recovering caribou abundance to a point that will satisfy their legal treaty rights for hunting (Government of Canada, 1899).…”

“…However, the Province of British Columbia allowed non‐Indigenous Peoples to hunt these caribou until 2003, almost 30 years after the Nations ceased harvest (Ministry of Water Land and Air Protection, 2002 ). Such asymmetry in the detection of population concerns for these caribou highlights one difference between stewardship by Indigenous Peoples frequently observing the landscape and western science approaches, which relied on population surveys and collaring that did not occur consistently until 2002 (McNay et al, 2022 ).…”

“…The loss of the Burnt Pine caribou occurred despite repeated attempts by the WMFN to protect the habitat from mining and logging, including several legal challenges (Muir & Booth, 2012 ; West Moberly First Nations, 2009 ). Meanwhile, the neighboring Klinse‐Za subpopulation fell from ~250 animals in the 1990s, to critically low levels of 38 animals by 2013 (Figure 3 , see McNay et al [ 2022 ] for detailed demographic analysis). A 2013 areal population survey of a portion of the Klinse‐Za subpopulation, formerly known as the Moberly subpopulation, counted only 16 animals.…”

“…The Klinse‐Za subpopulation totaled an estimated 38 caribou in 2013 (24 females) and had been declining at ~11% per year since 1995 (McNay et al, 2022 ). If action had not been taken, this subpopulation would have been functionally extirpated within the decade based on previous population viability analyses for small, endangered populations of woodland caribou in Alberta and British Columbia (Decesare et al, 2011 ; Wittmer et al, 2010 ), and recent projections using Klinse‐Za caribou (McNay et al, 2022 ).…”

Efficacy and ethics of intensive predator management to save endangered caribou

“…Justifications such as “wolves are nowhere near endangered or threatened in Canada” or “there is a long history of predator (and prey) reduction to recover endangered species” (Serrouya et al, 2019; 6184) are not compelling arguments for those who find many of the methods of control as inhumane or that have deep philosophical objections to killing one species to save another (Brook et al, 2015; Fox & Bekoff, 2011). Although there is considerable evidence to support the tactical use of predator management as one tool for maintaining caribou over the short‐term (Bridger, 2019; Hervieux et al, 2014; McNay et al, 2022; Russell, 2010), there is no graceful way to divorce efficacy from the values held by society and the normative or prescriptive ethics that guide our activities as conservation professionals.…”