Dynamics, Persistence, and Genetic Management of the Endangered Florida Panther Population

Abstract

Abundant evidence supports the benefits accrued to the Florida panther (Puma concolor coryi) population via the genetic introgression project implemented in South Florida, USA, in 1995. Since then, genetic diversity has improved, the frequency of morphological and biomedical correlates of inbreeding depression have declined, and the population size has increased. Nevertheless, the panther population remains small and isolated and faces substantial challenges due to deterministic and stochastic forces. Our goals were 1) to comprehensively assess the demographics of the Florida panther population using long‐term (1981–2015) field data and modeling to gauge the persistence of benefits accrued via genetic introgression and 2) to evaluate the effectiveness of various potential genetic management strategies. Translocation and introduction of female pumas (Puma concolor stanleyana) from Texas, USA, substantially improved genetic diversity. The average individual heterozygosity of canonical (non‐introgressed) panthers was 0.386 ± 0.012 (SE); for admixed panthers, it was 0.615 ± 0.007. Survival rates were strongly age‐dependent (kittens had the lowest survival rates), were positively affected by individual heterozygosity, and decreased with increasing population abundance. Overall annual kitten survival was 0.32 ± 0.09; sex did not have a clear effect on kitten survival. Annual survival of subadult and adult panthers differed by sex; regardless of age, females exhibited higher survival than males. Annual survival rates of subadult, prime adult, and old adult females were 0.97 ± 0.02, 0.86 ± 0.03, and 0.78 ± 0.09, respectively. Survival rates of subadult, prime adult, and old adult males were 0.66 ± 0.06, 0.77 ± 0.05, and 0.65 ± 0.10, respectively. For panthers of all ages, genetic ancestry strongly affected survival rate, where first filial generation (F1) admixed panthers of all ages exhibited the highest rates and canonical (mostly pre‐introgression panthers and their post‐introgression descendants) individuals exhibited the lowest rates. The most frequently observed causes of death of radio‐collared panthers were intraspecific aggression and vehicle collision. Cause‐specific mortality analyses revealed that mortality rates from vehicle collision, intraspecific aggression, other causes, and unknown causes were generally similar for males and females, although males were more likely to die from intraspecific aggression than females. The probability of reproduction and the annual number of kittens produced varied by age; evidence that ancestry or abundance influenced these parameters was weak. Predicted annual probabilities of reproduction were 0.35 ± 0.08, 0.50 ± 0.05, and 0.25 ± 0.06 for subadult, prime adult, and old adult females, respectively. The number of kittens predicted to be produced annually by subadult, prime adult, and old adult females were 2.80 ± 0.75, 2.67 ± 0.43, and 2.28 ± 0.83, respectively. The stochastic annual population growth rate estimated using a matrix population model was 1.04 (95% CI...

Vital rates of two small populations of brown bears in Canada and range‐wide relationship between population size and trend

“…Our findings support the theory that as populations decline, we can expect wide variations in vital rates that diverge from those common for the species, potentially exacerbating the rate of decline (Lande, 1998). Also, that small, isolated populations of large carnivores may not respond as well to recovery actions that were successful for larger, or more connected populations of the same species (Fanshawe et al, 1991;Ferreras et al, 2001;Groom et al, 2014;Tosoni et al, 2017). For many carnivores, this means that solely focusing on reducing adult mortality is likely to be insufficient to promote recovery and should not be the only conservation strategy.…”

“…The random fluctuations in birth and death events have very little effect on population growth in large populations; however, in small populations, simultaneous “bad luck” among few individuals can cause the population to decline to zero (Engen & Sæther, 1998). Fortunately, inbreeding and loss of genetic diversity are potentially reversible by restoring gene flow via augmentation or natural immigration (Åkesson et al., 2016; Poirier et al., 2019; Quinn et al., 2019; van de Kerk et al., 2019; Yumnam et al., 2014). An example is the genetic restoration of the Florida panthers ( Puma concolor coryi ) from population augmentation (Johnson et al., 2010) that increased survival of first generation admixed panthers in all age classes (van de Kerk et al., 2019).…”

“…For small populations, with inevitably small sample sizes, acquiring data required for strong inferences is improbable (Mosnier et al, 2015;Zipkin & Saunders, 2018). As a result, estimates of vital rates and causes for their suppression are seldom obtained in wild populations with few individuals (e.g., Tosoni et al, 2017;Wittmer et al, 2005), despite their world-wide relevance for the development of effective conservation strategies.…”

“…Successful conservation requires an understanding of the initial causes of decline and those that might be specific to small, remnant populations (Brook et al., 2008; van de Kerk et al., 2019). Many threatened large carnivore species are wide‐ranging, occur at low‐density, and have long generation times.…”

Spatiotemporal Genetic Diversity of Lions

“…Many species across Africa are declining due to human-induced threats (14)(15)(16), even in protected areas (16). The adverse effects of low genetic diversity have been observed in small feline populations that exist in heavily managed fenced reserves (17)(18)(19)(20)(21). Historically, the lion (Panthera leo) range was more continuous and connected (22).…”