Population Dynamics of the Florida Softshell Turtle (Apalone ferox) in a Protected Spring Ecosystem

Area of Science:

• Herpetology
• Wildlife Ecology
• Population Dynamics

Background:

• The Florida softshell turtle (Apalone ferox) is widespread but poorly understood due to capture difficulties.
• Previous research established a foundation from 2007-2012 at Wekiwa Springs State Park (WSSP).

Purpose of the Study:

• To extend the foundational study with a 16-year mark-recapture analysis (2007-2023).
• To estimate population size, survival, and detection probabilities for Apalone ferox.
• To assess the WSSP ecosystem as a potential nursery habitat.

Main Methods:

• Conducted 31 sampling events over 16 years, totaling 88 capture days.
• Captured and marked 120 individual Apalone ferox over 225 encounters.
• Utilized Schumacher-Eschmeyer and state-space Jolly-Seber models for population estimation.

Main Results:

• Estimated an average population size of 135.6 individuals.
• Estimated 204 individuals entered the superpopulation, with an average current population of 40.
• Median survival probability was 0.884, while median detection probability was low at 0.10.

Conclusions:

• The WSSP ecosystem may function as a nursery habitat, evidenced by juvenile influx and adult recaptures.
• Population estimates showed a temporary decline post-COVID-19 but are now slowly growing.
• Long-term monitoring is crucial for understanding elusive freshwater turtle populations.