American alligators (Alligator mississippiensis) are managed quite differently than most other fish and wildlife species in the United States. As reptiles, they do not fall within the ‘fur and feathers’ category traditional to state wildlife management, which typically receives the bulk of attention, management, and funding. Despite harvest in aquatic habitats, they are also not considered a fishery and are not managed as such. The unique nature of their status has resulted in comparatively less research and management, contributing to significant uncertainties which can hamper decision making. Such challenges are only exacerbated by paradoxical social views of alligators. They are simultaneously considered a nuisance animal with the capacity to threaten human safety, a species of conservation focus due to previous listing under the Endangered Species Act, and a desired hunted species. In some locations, alligators are a flagship species, integral to the identity and tourism of places like Everglades National Park. Such tradeoffs understandably make decision making difficult, which is only compounded by the lack of information and resources dedicated to alligator management and study. Further research into the status and uncertainties of alligator populations falls squarely within the goal of the State and Tribal Wildlife Grants (SWG) Program—to ensure common species remain common and to prevent species from falling through the cracks. Monitoring and understanding alligator populations is crucial to maintain healthy populations, but also because of their status as an indicator of ecosystem health. Living in a variety of wetland habitats, alligators are both apex predators and ecosystem engineers. Alligator populations are particularly sensitive to environmental changes and overharvesting, making them valuable indicators of ecosystem conditions and the effectiveness of management interventions. Studying these populations, however, presents several challenges. Alligators’ long life spans, which can exceed 60 years in the wild, mean that many individuals will outlive a typical research program, thus limiting our understanding of population dynamics over their lifetimes. Given the benefits of alligators to the ecosystem, hunters’ desire for alligator harvest in Georgia, and the SWG goal to prevent species from becoming endangered, research to gain a better understanding of alligator population size and dynamics is needed to enable Georgia DNR to make harvest management decisions that balance hunter satisfaction and population sustainability. The complex social views and unclear management status of alligators, combined with a long-life history and challenges of field studies, has led to significant uncertainties regarding alligator populations in the Southeast. Improved understanding of alligator populations will support better decision-making on harvest management to prevent overexploitation, while also considering the public desire for tags. The objective of this work is to estimate alligator population size and structure with simulations of various harvest quotas in the state of Georgia. Multiple types of data, collected by Georgia Department of Natural Resources (DNR) over decades, will be synthesized into an integrated population model. The model will be customizable to the type and amount of uncertainty based on available data and information from species experts. Additionally, we will simulate the population under varying harvest levels to test the sensitivity of population to harvest to inform Georgia DNR’s alligator tag allocations. Building on the population model, the second objective is to identify key areas of uncertainty in our knowledge of Georgia alligator populations (e.g., age, location, movement) through value of information analysis (VoI). Such identification will help inform the allocation of research efforts to reduce uncertainty and inform optimal decisions for harvest management. The third objective is to develop an optimal monitoring plan for alligator populations considering limited agency resources. This objective will focus on creating an achievable monitoring plan to inform management decisions for alligators in Georgia under the constraints of limited agency funding and personnel. The plan will integrate the results of the first two objectives to guide monitoring recommendations, while also capturing the limitations associated with on the ground monitoring activities. This research is expected to significantly improve the understanding of alligator populations in Georgia, providing valuable insights for effective harvest management and informed decision-making. By integrating decades of data into an integrated population model (IPM), we will estimate population size and structure and quantify the uncertainty surrounding these estimates. Simulations of varying harvest levels will help inform more accurate harvest quotas, while a value of information (VoI) analysis will guide DNR in prioritizing research efforts to reduce the most critical uncertainties. This work will enhance the ability to balance the need for sustainable harvest management with public demand for alligator tags, ultimately contributing to more informed, evidence-based conservation strategies. Furthermore, the findings will be directly applicable to DNR’s ongoing research program, with recommendations tailored to optimize resource allocation and improve future population monitoring efforts. Broadly, this work will serve as an example of effective estimation for data deficient species and science-driven research guidance.
Funder: Georgia Department of Natural Resources
Amount: $247,824
PI: Kelly Robinson, Warnell School of Forestry and Natural Resources
