Post-delisting dilemma: Long-term success of Chrysopsis floridana introductions depends on continued fire management

Abstract

The Endangered Species Act aims to recover imperiled species to the point of delisting; however, few plant species have been delisted due to recovery. Critical to many species' recovery criteria are introductions, yet the long-term success of plant introductions is highly variable and their use in delisting decisions is relatively untested. In this study, we examined the dynamics of eight introduced populations of the recently delisted Chrysopsis floridana (Florida Golden Aster), a fire-dependent perennial plant endemic to Florida scrub habitats. We analyzed 6 years of demographic data (2017–2022) and 10 years of prescribed fire records to assess population trends, fire management effects, and vital rates related to recruitment, survival, and reproduction. Our results show that population densities with regular fire management increased, while unburned populations generally declined. Prescribed fire increased seedling recruitment and survival rates. We estimated a fire-return interval of approximately 5 years is needed for population persistence, shorter than the 10-year interval used in the delisting decision. Our findings suggest that post-delisting monitoring should prioritize fire management to ensure the long-term success of introduced populations. Our work highlights the need for more robust, specific delisting criteria, particularly regarding the role of introductions, long-term monitoring, and post-introduction habitat management. These insights can inform future recovery plans for fire-dependent species and improve the delisting process for plants under the Endangered Species Act.