PS 36-77 - Effects of road development on decreasing population of the endangered florida panther

Wednesday, August 9, 2017
Exhibit Hall, Oregon Convention Center
Anna Cole, Hsiao-Hsuan Wang and William E. Grant, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX
Background/Question/Methods

The Florida panther, Puma concolor coryi, historically roamed throughout the Southeastern United States from Louisiana to Southwestern Florida. Due to habitat degradation from increased development, the subspecies experienced a drastic population decline that led to an influx in negative inbreeding effects that lowered the survival rates. Such inbreeding effects include a kinked caudal vertebrae, a cowlick in the caudal fur, and reproductive problems including cryptorchidism. The introduction of 8 Texas cougars, Puma concolor, into the population of Florida panthers increased the genetic diversity and population. Despite this population increase, the subspecies continues to experience threats from continued development of expanding roadways through vital habitat, specifically that of Big Cypress National Preserve and the Florida Panther National Wildlife Refuge. Our objective is to determine the extent of population loss of the Florida panther due to roadway development and automobile traffic. Data compiled on Google Earth by the Florida Fish and Wildlife Conservation Commission was used to create a spreadsheet in Excel documenting the time and location of roadkills and presences in Florida from 1972 to 2015. We then used boosted regression trees to identify potential factors influencing the likelihood of roadkills, and quantify the relative importance of each factors.

Results/Conclusions

Based on the data obtained through the Google Earth maps provided by the Florida Panther Conservation Commission, the number of lanes and the presence of fences and/or medians were decided to be the important factors of roadkills. Of the 291 instances of roadkills and sightings, 219 occurred on roadways consisting of two or less lanes, while only three occurred on roadways of eight or more lanes. Additionally, fences were present in 95 of these events and medians were present in 67 occurrences. The number of lanes had a 66% relative contribution to roadkills, while the presence of fences and medians had relative contributions of 31.4% and 2.6%, respectively. These results suggest that of the three factors, the number of lanes has the greatest importance to the occurrence of roadkills. However, roadkills are most likely to occur on roadways containing two or less lanes, suggesting that panthers have a preference for roadways with fewer lanes. The higher occurrence of roadkills and sightings on roadways without fences and medians suggests that panthers successfully cross areas with these features, though their importance is lower than that of the size of the roadway itself.