This project links water balance and carbon budgets to Ecosystem Function and Services (EF&S) in a mangrove estuary while developing strategies for integrating this science into decision-making forums for allocating regional water resources. The study area is the largest mangrove forest in North America, which is located within Everglades National Park (ENP). The project's goals are being accomplished through two open workshops and a focused field experiment. The project leverages ongoing work by the Florida Coastal Everglades Long Term Ecological Research program (FCE-LTER) and other programs associated with Everglades restoration.
The first open workshop is devoted to evaluating linkages between mangrove carbon and water budgets, the ecosystem services provided by the estuary, and the economic value of these services. This workshop brings together a diverse set of experts in water resources engineering, climatology, mangrove estuary hydrodynamics, carbon cycling, fish behavioral ecology, recreational fisheries, and Everglades restoration. Workshop participants identify research needed to assess changes in mangrove EF&S caused by altered freshwater discharge, sea level rise, and climate variability. Break-out sessions are focused on developing a better understanding of 1) the economic value of the ecosystem services, in part related to Carbon sequestration capacity and 2) linkages between freshwater inputs and the economic value of recreational fishing in ENP using a 30+ year record of fishing practices.
The focused field experiment will investigate linkages between water and carbon cycles. In this experiment, a tracer is followed downstream through several tidal cycles. Samples from within the labeled water plume are collected to measure concentrations and Carbon-13 to Carbon-12 ratios of dissolved organic and inorganic Carbon. The chemical and isotopic composition and molecular structures of the dissolved compounds are used to differentiate between freshwater and marine carbon sources. Isotope approaches are also used to delineate fish foraging behavior along the fresh/saltwater transition zone. In this mangrove forest, eddy covariance estimates of net ecosystem-atmosphere exchange of water vapor and carbon dioxide have been made since 2004 and provide important constraints on the ecosystem water and carbon budgets.
The second open workshop focuses on developing an empirical and methodological framework to assess changes in EF&S and on integrating the results into resource management and restoration cost/benefit analyses. Specific focus is placed on understanding how intangible personal or societal values may influence decision-making more than cost-benefit analyses. Thus, the second workshop has a broader scope in both participant expertise and discussion points than the first.
Improved understanding of water balance and carbon budgets in tropical mangrove estuarine systems and their dependence on management, climate change, and sea level rise can help protect mangrove forests and ensure the continuation of EF&S they provide, including carbon sequestration, fisheries support, storm protection, water purification, and recreation. Tangible economic and less tangible personal or societal values placed on these services are being considered to determine the appropriate management strategies and responses to ecological stressors associated with, for example, a changing climate. Thus, this project represents a first step toward integrating a comprehensive evaluation of mangrove EF&S into the regional water resource management plan affecting the six million inhabitants and unique ecosystems of south Florida which, because of its low-lying topography and extensive coastal wetlands, faces significant risks from sea level rise. This framework can serve as a model for managing estuaries throughout the tropics, with far-ranging implications.
Minority graduate students are being recruited from within Florida International University and other minority-serving institutions to participate in this study. Junior investigators are invited to participate and assume leadership roles in the workshops. Outcomes from the project are broadly disseminated through presentations at various venues, including civic and environmental organizations and government agencies.
