PS 11-47 - Effects of genetic depletion on estimating risk of extinction of the endangered Florida panther

Tuesday, August 9, 2016
ESA Exhibit Hall, Ft Lauderdale Convention Center
Anna Cole1, Kelsea Anthony1, Chris Chen2, Hsiao-Hsuan Wang1, Tomasz E. Koralewski3 and William E. Grant1, (1)Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, (2)Department of Animal Science, Texas A&M University, College Station, TX, (3)Department of Ecosystem Science and Management, Texas A&M University, College Station, TX

The Florida panther (Puma concolor coryi), a subspecies of the cougar, is an iconic and essential mesopredator of southern Florida. Once widespread throughout the southeastern United States, the panther population is now restricted to two isolated patches in Everglades National Park and Big Cypress National Preserve. Consequently, they have been classified as “endangered” by the U.S. Federal List. Urbanization encroachment, habitat fragmentation, and human-wildlife conflicts have had a devastating impact upon this subspecies. The population went through a bottleneck, dipping below 100 individuals, that has likely lead to a detrimental loss of genetic diversity. Resulting inbreeding depression is manifested through apparent compromised reproductive and physiological fitness of the subspecies. In 1995, the Fish and Wildlife Service captured and released eight female Texas cougars, a related subspecies, into the Florida panther habitat to increase genetic diversity of the latter. Prior to 1995, panther populations had been declining at an annual rate of 5%. After the genetic diversity restoration efforts started, population is now found to be increasing at an annual rate of 3–4%. The objective of our study is to determine how the genetic depletion could affect the population dynamics of Florida panther. We conducted a thorough literature review to obtain the best basic demographic data available and developed a stage-structured population dynamics model for Florida panther. We then used the model to test the potential effects of genetic depletion on the populations of Florida panther.


When mortality rate parameters were changed to maximum values, the simulated Florida panther population was close to extinction after 25 years, while the population size reached over 1700 when the parameters were set to minimum values. When each stage mortality rate was altered individually while the others remained at baseline, the population size was ranged from 0 to around 10 panthers after 25 years. The natality parameters, however, had much different results; when only natality was manipulated in the model, the population ranged from 0 to 218. These results suggest that natality rates play an important role to sustain the population of Florida panther. Such a scenario can happen by increasing available genes in the gene pool, which happened with the 8 Texas cougars bred with the native Florida panthers.