The Department of Defense (DoD) is tasked with managing lands that support populations of threatened, endangered, and at-risk species (TES). Impacts on these DoD-relevant TES populations may affect military training or restrict use of military lands, even for reasons beyond the control of military land managers. Within this context, understanding how common stressors interact to affect populations of multiple TES is a critical research need. The research objective in this project is to understand how the widespread stressors of fire, fire ant density, and cattle grazing interact to affect populations of a variety of TES on DoD and adjacent lands of the southeastern U.S. This project is focused on understanding outcomes for wildlife species (birds, herpetofauna, mammals) managed on military lands. Results from the project will be used to inform population models for TES. Model outputs will be used to develop ecosystem-based management strategies to mitigate the interactive threats of these common stressors on multiple co-distributed TES of birds, herpetofauna, and mammals in upland ecosystems.
The project will be conducted at Avon Park Air Force Range (APAFR), Florida and nearby non-military lands. The project will be a series of field experiments conducted in pine flatwoods, dry prairie, and oak scrub ecosystems at APAFR and the DeLuca Preserve, managed by the University of Florida. Because ecosystems similar to these are present throughout the southeastern U.S., results from this research can be transferred to many DoD installations with these or similar ecosystems that have similar vertebrate species assemblages and the same, common stressors (e.g., Camp Blanding, FL, Fort Jackson, SC; Fort Benning, GA; Eglin Air Force Base, FL; Fort Polk, LA; etc.). In year 1, biological surveys will be conducted to determine how current and historical burning practices on APAFR have structured plant communities and fire ant population densities in different upland habitats harboring a variety of TES. These surveys will also show the distribution, abundance, and diversity data for the TES wildlife of interest. In years 2-4, a series of experiments will be conducted in each of the different habitats to determine the interactive effects of the three stressors on TES species present in the habitat types at APAFR and the DeLuca Preserve. Burning frequency, fire ant density, and grazing will be manipulated in each of the three habitat types to determine both the individual impact of stressors and how these stressors affect TES populations in combination. Beginning in year 1, an integrated and multi-modeling approach will be used to integrate first-year survey data into the design and layout of experiments. In years 2-4, results from experiments will be used to develop models to inform how management of fire and fire ants may affect TES outcomes on APAFR. For TES and other species with only occurrence data available, the primary modeling framework for exploring population response to stressors will rely upon occurrence probabilities to inform the understanding of local extinction/colonization patterns and occupancy of experimental plots. For TES with habitat, count and capture-recapture data, such as Florida scrub-jay and gopher tortoise, the project team will integrate count and habitat data with demographic parameters data using hierarchical modeling approaches and/or population viability analysis. Modeling outputs will aid in determining which management changes may influence persistence for multiple TES species.
The research will address the identified needs of effective stewardship of the species and ecosystems present on military lands, while supporting and benefiting the military mission of the installations. This research will provide a baseline for understanding the effect of current and possible future management for many TES species and permit flexibility in how the military chooses to respond to and affect common stressors as likely impacts on a variety of species will be known. The results will also provide a “proof of concept” for addressing interacting threats, which can be expanded to other DoD installations regionally and nationwide.