Paradoxes and synergies: optimizing management of a deadly virus in an endangered carnivore

Management of pathogen transmission is often hindered by uncertainties in the efficacy of and interactions between intervention strategies, sometimes resulting in unintended negative consequences. Yet outbreaks of infectious disease can have serious consequences for wildlife population health, especially species of conservation concern. The endangered Florida panther, for example, experienced an outbreak of feline leukemia virus (FeLV) in 2002-2004, and continues to be affected by this deadly virus. Ongoing management efforts aim to mitigate the effects of FeLV on panthers with limited empirical information about which strategies are most effective and efficient. We used a simulation-based approach to determine optimal FeLV management strategies. We simulated use of proactive management interventions (i.e., proactive vaccination) as well as three reactive strategies, including vaccination in the face of an outbreak, test and removal protocols, and temporary spatial segregation of the panther population. Vaccination strategies included partial vaccine immunity, an understudied type of vaccine imperfection. We compared the effectiveness of different strategies in mitigating FeLV mortalities and duration of outbreaks. Results showed that inadequate proactive vaccination can paradoxically increase the number of disease-induced mortalities in FeLV outbreaks, at least in part due to partial vaccine immunity. Combinations of proactive vaccination with reactive test- and-removal or vaccination had a synergistic effect in reducing impacts of FeLV outbreaks. Temporary spatial restrictions were unlikely to be effective under realistic conditions. Our results highlight the importance of integrating management and modeling approaches to identify unexpected consequences and synergies in pathogen management interventions and aid in conservation of at-risk species.Significance StatementManaging outbreaks of infectious disease is fraught with uncertainties such that seemingly helpful interventions can have unintended negative consequences. We used a simulation approach to determine optimal pathogen management strategies in an endangered carnivore, the Florida panther (Puma concolor coryi), which continues to be affected by outbreaks of feline leukemia virus. We tested interventions including proactive vaccination, reactive vaccination, test-and-removal, and temporary spatial restrictions. We found that inadequate proactive vaccination can counterintuitively increase disease-related mortalities. In contrast, we identified synergies between proactive and reactive strategies that will be key for ongoing conservation of the iconic Florida panther. The results of this study demonstrate the importance of linking modeling and management to optimize pathogen control and avoid unexpected negative consequences.

Spatiotemporal pattern of interactions between an apex predator and sympatric species

Increases in apex predator abundance can influence the behavior of sympatric species, particularly when the available habitat and/or resources are limited. We assessed the temporal and spatiotemporal interactions between Florida panthers (Puma concolor coryi) and six focal sympatric species in South Florida, where Florida panther abundance has increased by more than 6-fold since the 1990’s. Using camera trap data, we quantified species’ diel activity patterns, temporal overlap, and time-to-encounter (i.e., time between consecutive visits of a Florida panther and a focal species and vice versa). The Florida panther and bobcat (Lynx rufus) displayed a nocturnal activity pattern; the black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus), wild boar (Sus scrofa), and wild turkey (Meleagris gallopavo) were mostly diurnal; and the raccoon (Procyon lotor) was cathemeral. Prey species and black bears minimized encounters with Florida panthers by being active during the day and displaying longer time-to-encounter, whereas Florida panthers visited a site after a prey species at higher probabilities than after competitor species, and were more likely to visit an elevated site or upland habitat. Our results suggest that interactions between Florida panthers and sympatric species in our study system are driven by species-specific behavioral responses. Gaining a better understanding of the crucial interactions driving species coexistence is important for a better understanding of the structure and function of ecological communities and help manage the potential expansion of the Florida panther into Central Florida.

Reproductive characteristics and performance of the Florida panther: a retrospective examination of long-term data

Knowledge of reproductive characteristics and performance (RCP) is necessary to estimate a species’ breeding output and provide indicators to evaluate population health and sustainability. Long-term data is important because it provides insights into the role of intrinsic and extrinsic factors in determining RCP and lifetime breeding output of individuals and productivity of populations. In this paper, I examine the RCP of the Florida panther Puma concolor coryi using an extensive data set collected from 1981-2019. My objective is to establish baseline RCP parameters and to determine the factors that affect lifetime breeding output. Briefly, the results from a variety of data analyses show: 1) Florida panthers exhibit a spring (March-May) birth pulse; 2) minimum age at sexual maturity do not differ between sexes; 3) mean annual proportion of radio-collared females reproducing, litter size, and birth rate progressively decrease with increasing maternal age; 4) mean litter sex ratio is male-biased; 5) mean birth interval differs between successful and unsuccessful litters; 6) proportion of kittens that recruited into the breeding population is small; and, 7) distribution of parentage and mating partners among individuals in litters of known mothers and fathers is right-skewed. The results indicate that breeding output is limited both by low birth rate and small proportion of offspring recruiting into the breeding population. The decreasing RCP with increasing maternal age suggests that costs of reproduction and progressive body condition senescence are important factors limiting lifetime breeding output. Despite these inhibiting factors, the data came from a period of substantial population growth and expansion since 1995 so the RCP shown is productive for this species. Outcomes from this study provide important RCP information for wildlife managers to implement measurable criteria to assess trends in this species’ breeding output.

Wildlife of Florida Factsheet: Florida Panther

Learn more about the Florida Panther! The Wildlife of Florida Factsheet series was created to provide the public with a quick, accurate introduction to Florida?s wildlife, including both native and invasive species. Authors Kelly Koriakin and Raoul Boughton hope this 2-page quick guide and others in the series published by the UF/IFAS Department of Wildlife Ecology and Conservation will inspire readers to investigate wildlife in their own backyards and communities and understand the amazing biodiversity of wildlife in the state of Florida.https://edis.ifas.ufl.edu/uw467

Altered lentiviral infection dynamics follow genetic rescue of the Florida panther

Wildlife translocations are a commonly used strategy in endangered species recovery programmes. Although translocations require detailed assessment of risk, their impact on parasite distribution has not been thoroughly assessed. This is despite the observation that actions that alter host–parasite distributions can drive evolution or introduce new parasites to previously sequestered populations. Here, we use a contemporary approach to amplify viral sequences from archived biological samples to characterize a previously undocumented impact of the successful genetic rescue of the Florida panther ( Puma concolor coryi ). Our efforts reveal transmission of feline immunodeficiency virus (FIV) during translocation of pumas from Texas to Florida, resulting in extirpation of a historic Florida panther FIV subtype and expansion of a genetically stable subtype that is highly conserved in Texas and Florida. We used coalescent theory to estimate viral demography across time and show an exponential increase in the effective population size of FIV coincident with expansion of the panther population. Additionally, we show that FIV isolates from Texas are basal to isolates from Florida. Interestingly, FIV genomes recovered from Florida and Texas demonstrate exceptionally low interhost divergence. Low host genomic diversity and lack of additional introgressions may underlie the surprising lack of FIV evolution over 2 decades. We conclude that modern FIV in the Florida panther disseminated following genetic rescue and rapid population expansion, and that infectious disease risks should be carefully considered during conservation efforts involving translocations. Further, viral evolutionary dynamics may be significantly altered by ecological niche, host diversity and connectivity between host populations.