Prescribed fire promotes colonization by the Florida bog frog

Abstract

Background: Understanding the link between prescribed fire and occupancy dynamics can aid in managing at-risk species. Knowledge of how fire return interval influences rates of colonization and persistence is essential to effectively mitigate extinction risk, particularly for species endemic to fire-maintained habitats with restricted geographic ranges. The current geographic range of the Florida bog frog (Rana okaloosae, hereafter bog frog) is largely restricted to one military installation in the Florida panhandle. The bog frog is currently listed as a state species of special concern owing to its inherent rarity and habitat loss across its limited range. We conducted call surveys for bog frogs at 151 stream-associated sites on Eglin Air Force Base from 2006 to 2022 to map their distribution and evaluate the effectiveness of habitat management. We constructed a spatially explicit, dynamic occupancy model to identify habitat characteristics associated with bog frog presence and quantify the effect of prescribed fire on turnover dynamics.

Results: Historical fire return interval was the only predictor of initial site occupancy; sites that burnt every 2 years on average from 1985 to 2005 were twice as likely to be occupied in 2006 as sites that burnt once every 10 years in that time period. Additionally, we found that colonization rates were a function of proximity to neighboring sites and burn frequency. Most dispersal events occurred between sites less than 0.33 km apart and unoccupied sites more than 2 km from their nearest neighbors were never colonized. Colonization rates were higher at sites that had seen an increase in burn frequency during the study period compared to the preceding two decades.

Conclusions: The bog frog benefits from frequent fire in its native stream habitat. Conservation activities should focus on protecting high-quality sites and targeted burns to restore fire-suppressed sites near occupied sites. More broadly, our study highlights the value of long-term monitoring to ensure management activities for at-risk species match the scale of dynamic biological processes.