Files
Abstract
White-tailed deer (Odocoileus virginianus) are the primary prey of the endangered Florida panther (Puma concolor coryi) in South Florida, USA where reports of deer population declines have caused stakeholders concern. I used camera and GPS-telemetry data collected from January 2015 through December 2017 to evaluate the distribution, abundance, and demography of deer in the Big Cypress National Preserve and Florida Panther National Wildlife Refuge. I developed a generalized spatial-mark-resight (SMR) model, which revealed density was highest in the drier, western portion (4.3 females/km2) and lowest in the wetter, eastern region (1.3 females/km2). Temporal variation in density was driven primarily by seasonal environmental conditions. Long-term SMR trend estimates were negative at all sites, but the rate of decline was only significant at one site (β1 = -0.074); annual decline was 1.92 females/km2/yr. Using spatial-mark-resight models and objective weighting, I identified the optimal monitoring design for future long-term, camera-based studies of deer in the region. The most effective use of available resources involves a camera design with 40 on-trail cameras spaced a minimum of 250 m apart within a 25-km2 area. I assessed deer population viability by calculating population growth and growth rate sensitivity using vital rates and density estimates from pre- and post-panther genetic restoration. Although I found evidence that the deer population growth has declined since the panther restoration (λ=0.845), estimates of population growth suggest the deer population was already declining prior to restoration efforts in 1995 (λ=0.957), which is consistent with results from aerial monitoring. This suggests that other factors such as poor soil fertility, hydrology, the predator community, and hunting regulations may have negatively affected the population. While our results do not support the conclusion that panthers have caused the deer population declines, they do indicate that predator restoration has sped up the declines, which could threaten the long-term viability of the panther population unless either management can intervene to bolster the prey population, or cyclic predator-prey dynamics allow the deer population to recover.