Paleoenvironmental Reconstructions Improve Ecosystem Services Risk Assessment: Case Studies from Two Coastal Lagoons in South America

Paleoenvironmental reconstructions are increasingly being used in conservation biology, ecosystem management, and evaluations of ecosystem services (ES), but their potential to contribute to the ES risk assessment process has not been explored. We propose that the long-term history of the ecosystem provides valuable information that augments and strengthens an ES risk assessment and that it should be considered routinely when undertaking risk assessments. We adjusted a standard ecosystem-based risk management (EBRM) protocol to include paleoenvironmental data, and tested the modified approach on two coastal lagoons in South America. Paleolimnological reconstructions in both lagoons indicate that salinity and nutrients (in Laguna de Rocha), and salinity (in Ci\ enaga Grande de Santa Marta), as controlled by hydrologic connectivity with the ocean and freshwater tributaries, have been the key variables behind ecosystems' function. This understanding, applied to inform various components and steps in the EBRM protocol, suggests that the maintenance of hydrological connections should be a management priority to minimize risk to ES. This work illustrates the utility of including paleoenvironmental data in an EBRM context, and highlights the need for a more holistic approach to risk management by incorporating the long-term history of ecosystem function.