Multiple anthropogenic interventions drive puma survival following wolf recovery in the Greater Yellowstone Ecosystem

Abstract

Humans are primary drivers of declining abundances and extirpation of large carnivores worldwide. Management interventions to restore biodiversity patterns, however, include carnivore reintroductions, despite the many unresolved ecological consequences associated with such efforts. Using multistate capture–mark–recapture models, we explored age‐specific survival and cause‐specific mortality rates for 134 pumas (Puma concolor) monitored in the Greater Yellowstone Ecosystem during gray wolf (Canis lupus) recovery. We identified two top models explaining differences in puma survivorship, and our results suggested three management interventions (unsustainable puma hunting, reduction in a primary prey, and reintroduction of a dominant competitor) have unintentionally impacted puma survival. Specifically, puma survival across age classes was lower in the 6‐month hunting season than the 6‐month nonhunting season; human‐caused mortality rates for juveniles and adults, and predation rates on puma kittens, were higher in the hunting season. Predation on puma kittens, and starvation rates for all pumas, also increased as managers reduced elk (Cervus elaphus) abundance in the system, highlighting direct and indirect effects of competition between recovering wolves and pumas over prey. Our results emphasize the importance of understanding the synergistic effects of existing management strategies and the recovery of large, dominant carnivores to effectively conserve subordinate, hunted carnivores in human‐dominated landscapes.

Reintroduced wolves and hunting limit the abundance of a subordinate apex predator in a multi-use landscape

“…Wolves were protected from legal hunting during our study excepting 2012 and 2013, when a limited quota hunt was permitted from October 1 to December 31 of each year. Over the duration of our research, the number of wolves in the study area ranged between 10 and 91 individuals, the peak of which occurred in 2010 [21].…”

“…We estimated future puma abundance using a demographic model inclusive of seasonal fecundity and stage-specific survival rates operating on a six-month time step. Following Elbroch et al [21], we split each year into two six-month seasons, one in which there was regulated legal hunting for pumas, and the other during which hunting was not permitted. These seasons captured variation in effects due to human-caused mortality as well as other mortality: (i) pumas were legally hunted during a 'hunting season' running from 1 October to 31 March of the following year.…”

“…Wolves were reintroduced in Yellowstone National Park in the USA in 1995, shortly after which they expanded into adjacent multi-use landscapes. Between 2000 and 2015, the puma population in the southern Greater Yellowstone Ecosystem (GYE) declined by 48%, as explained by three primary causes of mortality: regulated human hunting of adult and subadult pumas, grey wolves killing puma kittens, and increased starvation across age classes, but especially subadults [21]. The southern GYE is a mosaic of variable human perturbations influencing local wildlife, including legal hunting of predators and ungulates, and subsidized primary production through watering grasslands and agriculture on private ranches and public lands.…”

Puma population limitation and regulation: What matters in puma management?

“…Females overlapped less with each other and were said to defend territories with sufficient food resources needed to maintain themselves and their offspring. Overlap of female home ranges and male and female home ranges was higher in winter when greater hunting opportunity was provided by aggregated ungulates, particularly elk, supported at an exaggerated density by supplemental winter feeding (Elbroch et al , ).…”

“…For clarification, Wallach et al () proposed that socially stable large carnivore populations exhibit self‐regulation through socially mediated internal mechanisms, including extended parental care, female reproductive suppression, infanticide by dominant females killing young of subordinate females, and female territoriality. Wallach et al (:1453) concluded, “Self‐regulation in large carnivores may ensure that the largest and the fiercest do not overexploit their resources.” After synthesizing 14 years of data on the SYE puma population, Elbroch et al () concluded that 3 factors most influenced puma survival: hunting mortality, reduction of primary prey (i.e., elk), and competition with wolves. Estimated adult puma densities in winter ranged from 0.29–1.0 adults/100 km 2 , one of the lowest recorded densities in North America.…”