Puerto Rico’s endangered coquí llanero frog is the smallest and one of the most threatened of Puerto Rico’s 17 coquí species. They are found in only three wetlands on the northern coast, leaving the species vulnerable to major storm events and rising sea levels.  Southeast CASC researchers are using a common financial strategy called modern portfolio theory as a tool to protect the coquí. 

A study led by Southeast CASC-supported USGS researchers Mitch Eaton, Adam Terando, and Jaime Collazo used modern portfolio theory to help identify optimal investments in conservation efforts for coquí llanero frogs. Like in financial markets, resource managers face risks and uncertain futures when making conservation investments. A “diversified” portfolio (one that spreads investments over various strategies that respond differently to environmental changes) is more likely to have stable outcomes under future uncertainties, making it an effective way to manage risk. The researchers modeled a variety of conservation strategies for the frog, considering protected habitats, climate projections for sea-level rise, precipitation, and temperature, and varying levels of funding. They developed two models with different trade-offs, both constrained by budget: one strategy focused on maximizing conservation benefits by relocating frogs to existing protected areas. The other prioritized buying new parcels of land for relocation, a higher cost investment, but one that resulted in lower extinction risks. The researchers also identified potential new sites for the frogs on Puerto Rico’s eastern side, expanding options for increasing the species’ range.  

This Southeast CASC study demonstrates how modern portfolio theory can be a valuable tool for managers considering different management options around purchasing land, restoring habitats, and relocating species, while accounting for budget constraints and future uncertainties. 

This study is supported by the Southeast CASC project, “Advancing Climate Change Adaptation Strategies for High Elevation and Endangered Lowland Coquí Frogs in the U.S. Caribbean.”