Evaluating Structural and Surface Elevation Recovery of Restored Mangroves

Science Center Objects

Hydrologic restoration is one of several approaches to rehabilitate mangroves on a large-scale. USGS evaluates how solely restoring tidal hydrologic flows affect the recovery of mangroves in Florida. 

Rookery Bay NERR, FL, USA

Rookery Bay NERR, Florida

The Science Issue and Relevance: Mangroves are forested wetlands that occur in tropical and sub-tropical climates globally. Historically, mangroves have sustained high rates of loss because of their position on the water’s edge that often impedes development. Mangrove losses have slowed in recent years, and efforts are underway globally to create, restore, or rehabilitate mangroves to re-establish or enhance the many goods and services they previously provided. Restoration can take on many forms, and in this project we are evaluating how restoring tidal hydrologic flows alone might affect recovery of mangroves in the Rookery Bay region of Florida, USA. Hydrologic restoration stands to provide one of the cheapest tools for rehabilitating mangroves on a large-scale, but individual projects need to identify specific benefits.

 

Methodologies for Addressing the Issue: Over a period of about 60 years, large portions of a mangrove forest on Rookery Bay National Estuarine Research Reserve died due to altered tidal hydrological flows associated with the construction of a road. This course unfolds globally time and time again in mangroves; death is slow and cryptic but complete. In response, local and regional efforts were successful in proposing and partially funding a hydrological restoration effort, and we anticipate that full restoration should begin within the next 5 years. In advance of hydrological restoration, we established forest inventory plots in seemingly healthy, transitioning, and completely dead mangroves to assess current condition and monitor future change. Our primary response variables include surface elevation change, soil development, and benthic community response.

Dead mangroves, Marco Island, FL, USA

Dead mangroves, Marco Island, Florida

Future Steps: This project will continue for at least a decade to ensure adequate time to rate success or failure of the hydrological restoration based on its influence on mangrove recovery. This project is also linked to a companion study established in Tampa Bay that investigates structural and surface elevation change in created mangroves across an age gradient. Together, these studies will help us understand what we can achieve from various mangrove restoration approaches in south Florida.