In the News
Below are a few abstracts of recent scientific articles regarding wild felids.
Dynamics, Persistence, and Genetic Management of the Endangered Florida Panther Population
Madelon van de Kerk et al. 2019. Wildlife Monographs 203(1):1-35.
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 = 0.72–1.41). An individual‐based population model predicted that the probability that the population would fall below 10 panthers within 100 years (quasi‐extinction) was 1.4% (0–0.8%) if the adverse effects of genetic erosion were ignored. However, when the effect of genetic erosion was considered, the probability of quasi‐extinction within 100 years increased to 17% (0–100%). Mean times to quasi‐extinction, conditioned on going quasi‐extinct within 100 years, was 22 (0–75) years when the effect of genetic erosion was considered. Sensitivity analyses revealed that the probability of quasi‐extinction and expected time until quasi‐extinction were most sensitive to changes in kitten survival parameters. Without genetic management intervention, the Florida panther population would face a substantially increased risk of quasi‐extinction. The question, therefore, is not whether genetic management of the Florida panther population is needed but when and how it should be implemented. Thus, we evaluated genetic and population consequences of alternative genetic introgression strategies to identify optimal management actions using individual‐based simulation models. Releasing 5 pumas every 20 years would cost much less ($200,000 over 100 years) than releasing 15 pumas every 10 years ($1,200,000 over 100 years) yet would reduce the risk of quasi‐extinction by comparable amount (44–59% vs. 40–58%). Generally, releasing more females per introgression attempt provided little added benefit. The positive effects of the genetic introgression project persist in the panther population after 20 years. We suggest that managers contemplate repeating genetic introgression by releasing 5–10 individuals from other puma populations every 20–40 years. We also recommend that managers continue to collect data that will permit estimation and monitoring of kitten, adult, and subadult survival. We identified these parameters via sensitivity analyses as most critical in terms of their impact on the probability of and expected times to quasi‐extinction. The continuation of long‐term monitoring should permit the adaptation of genetic management strategies as necessary while collecting data that have proved essential in assessing the genetic and demographic health of the population. The prospects for recovery of the panther will certainly be improved by following these guidelines. © 2019 The Authors. Wildlife Monographs published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.
Puma Population Limitation and Regulation: What Matters in Puma Management?
Logan, K. 2019. Journal of Wildlife Management 83(8):1652-1666
ABSTRACT: Wildlife managers require reliable information on factors that influence animal populations to develop successful management programs, including the puma (Puma concolor), in western North America. As puma populations have recovered in recent decades because of restrictions on human‐caused mortality, managers need a clear understanding of the factors that limit or regulate puma populations and how those factors might be manipulated to achieve management objectives, including sustaining puma and other wildlife populations, providing hunting opportunity, and reducing puma interactions with people. I synthesized technical literature on puma populations, behavior, and relationships with prey that have contributed to hypotheses on puma population limitation and regulation. Current hypotheses on puma population limitation include the social limitation hypothesis and the food limitation hypothesis. Associated with each of those are 2 hypotheses on puma population regulation: the social regulation hypothesis and the competition regulation hypothesis. I organize the biological and ecological attributes of pumas reported in the literature under these hypotheses. I discuss the validity of these hypotheses based on the limits of the research associated with the hypotheses and the evolutionary processes theoretically underlying them. I review the management predictions as framed by these hypotheses as they pertain to puma hunting, puma‐prey relationships, and human‐puma interactions. The food limitation and competition regulation hypotheses explain more phenomena associated with puma and likely would guide more successful management outcomes.
Decreasing available bobcat tags appear to have increased success, interest, and participation among hunters.
Allen, M. L. et al. 2019. Human Dimensions of Wildlife 24: 349-362.
ABSTRACT: Management of wildlife populations has changed in the last century, coinciding with decreasing hunter populations and interest. Supply and demand suggest that reducing available harvest permits should increase the perceived value of permits, leading to an increase in hunter interest and motivation. We used annual harvest data and hunter surveys to study the effects of decreasing the supply of permits over two decades in Wisconsin. The number of permits issued was important in the top models for annual bobcat harvest and hunter participation. The decrease in the supply of permits was strongly correlated with increases in the number of applications for permits (R2 = .82) and hunter participation (R2 = .93), whereas increased hunter interest (applications and participation) was correlated with hunter success (percent of filled permits; R2applications = .90, R2participation = .93). This increasing trend in hunter populations and interest runs counter to general decreasing trends across North America and highlights the critical role of permit supply in wildlife management.
Winter recreation and Canada lynx: reducing conflict through niche partitioning.
Squires, J. R., et al. 2019. Ecosphere 10: e02876.
ABSTRACT: Outdoor recreationists are important advocates for wildlife on public lands. However, balancing potential impacts associated with increased human disturbance with the conservation of sensitive species is a central issue facing ecologists and land managers alike, especially for dispersed winter recreation due to its disproportionate impact to wildlife. We studied how dispersed winter recreation (outside developed ski areas) impacted a reintroduced meso‐carnivore, Canada lynx (Lynx canadensis), at the southern periphery of the species’ range in the southern Rocky Mountains. On a voluntary basis, we distributed global positioning system (GPS) units to winter recreationists and documented 2143 spatial movement tracks of recreationists engaged in motorized and nonmotorized winter sports for a total cumulative distance of 56,000 km from 2010 to 2013. We also deployed GPS radio collars on adult Canada lynx that were resident in the mountainous topography that attracted high levels of dispersed winter recreation. We documented that resource‐selection models (RSFs) for Canada lynx were significantly improved when selection patterns of winter recreationists were included in best‐performing models. Canada lynx and winter recreationists partitioned environmental gradients in ways that reduced the potential for recreation‐related disturbance. Although the inclusion of recreation improved the RSF model for Canada lynx, environmental covariates explained most variation in resource use. The environmental gradients that most separated areas selected by Canada lynx from those used by recreationists were forest canopy closure, road density, and slope. Canada lynx also exhibited a functional response of increased avoidance of areas selected by motorized winter recreationists (snowmobiling off‐trail, hybrid snowmobile) compared with either no functional response (hybrid ski) or selection for (backcountry skiing) areas suitable for nonmotorized winter recreation. We conclude with a discussion of implications associated with providing winter recreation balanced with the conservation of Canada lynx.
Spatial organization and activity patterns of ocelots (Leopardus pardalis) in a protected subtropical forest of Brazil.
Azevedo, F. C. C. et al. 2019. Mammal Research 64: 503-510.
We estimated home range size and overlap and activity patterns of ocelots in a protected subtropical forest, the Iguaçu National Park (INP), in southwestern Brazil using a long-term dataset from 1990 to 2001. We expected that male ocelots would have larger home ranges than females and that ocelots would be primarily nocturnal. In general, we found large home ranges sizes, with male home ranges larger than females, and significant intra and intersexual overlap. In addition, ocelots were more active during crepuscular hours. The observed larger home ranges than in other sites and significant overlap observed may reflect weak territoriality of ocelots in our study. The activity patterns observed may reflect an increase in the consumption of more diurnal and crepuscular prey species, such as lizards and agoutis. The weak territoriality and more crepuscular activity patterns may be indicatives of the flexibility of this felid species’ ecology.