Effects of anthropogenic mortality on Critically Endangered red wolf Canis rufus breeding pairs: implications for red wolf recovery

Abstract

Following precipitous population declines as a result of intensive hunting and th century predator-control programmes, hybridization of the Critically Endangered red wolf Canis rufus with coyotes Canis latrans posed a significant challenge for red wolf recovery efforts. Anthropogenic mortality and hybridization continue to pose challenges; the increasing number of wolf deaths caused by humans has limited wolf population growth, facilitated the encroachment of coyotes into eastern North Carolina, and affected the formation and disbandment of breeding pairs. We assessed the effects of anthropogenic mortality on Canis breeding units during a -year period (-). Our results show that deaths caused by people accounted for .% of breeding pair disbandment, and gunshots were the primary cause of mortality. Red wolves replaced congeneric breeding pairs . % of the time when pairs disbanded under natural conditions or as a result of management actions. Since the mid s anthropogenic mortality has caused annual preservation rates of red wolf breeding pairs to decline by %, and replacement of Canis breeders by red wolves to decline by %. Our results demonstrate that human-caused mortality, specifically by gunshots, had a strong negative effect on the longevity of red wolf pairs, which may benefit coyotes indirectly by removing their primary competitor. Coyotes are exacerbating the decline of red wolves by pair-bonding with resident wolves whose mates have been killed.

Space Use and Habitat Selection by Resident and Transient Red Wolves (Canis rufus)

“…For example, wolves maximize reproductive fitness through group living and by defending year-round territories in which pack size influences success in territorial defense [8–12]. Human-caused killings of essential members (e.g., breeders) in wolf packs are problematic to recovery efforts because they destabilize social structures and increase reproductive failure [3,11–16]. For eastern wolves ( Canis lycaon ) and red wolves ( Canis rufus ), increased rates of human-caused mortality resulting in collapsed territories facilitates coyote ( Canis latrans ) encroachment and increased rates of hybridization between coyotes and wolves [3,14,16–18].…”

“…Human-caused killings of essential members (e.g., breeders) in wolf packs are problematic to recovery efforts because they destabilize social structures and increase reproductive failure [3,11–16]. For eastern wolves ( Canis lycaon ) and red wolves ( Canis rufus ), increased rates of human-caused mortality resulting in collapsed territories facilitates coyote ( Canis latrans ) encroachment and increased rates of hybridization between coyotes and wolves [3,14,16–18]. Consequently, recovery of the critically endangered red wolf has been challenging because of its vulnerability to extinction via anthropogenic mortality and hybridization with coyotes [3,16,19–23].…”

“…Indeed, transient individuals are known to exist in coyote [31–33], eastern wolf [17], and gray wolf [34–37] populations, but their ability to traverse expansive areas makes transients difficult to monitor and study without global positioning system (GPS) and satellite technology [33]. Despite these difficulties, transiency is recognized to have a functional role in the population dynamics of wolves through emigration and replacement of breeding residents lost to mortality [3,12–13,15,36]. …”

“…Consequently, Hinton et al [33] suggested that transiency was an important life-history strategy facilitating coyote metapopulation dynamics through dispersal and replacement of resident breeders. Indeed, Hinton et al [3] reported increased occurrence of coyote encroachment and replacement of resident red wolves after resident wolf breeders were killed by humans. Although red wolves exhibit assortative mating patterns [16,38], coyotes were capable of pair-bonding with surviving red wolves when no transient wolves were available to encroach into territories that were disrupted by anthropogenic mortality [3].…”

“…Indeed, Hinton et al [3] reported increased occurrence of coyote encroachment and replacement of resident red wolves after resident wolf breeders were killed by humans. Although red wolves exhibit assortative mating patterns [16,38], coyotes were capable of pair-bonding with surviving red wolves when no transient wolves were available to encroach into territories that were disrupted by anthropogenic mortality [3]. Consequently, pair-bonding with coyotes by surviving red wolf residents formed congeneric breeding pairs that hybridized [3,22,33].…”