Climate Change

Mangrove forests have migrated inland over the past few decades at many locations along the northern Gulf of Mexico coast. This expansion has been attributed to factors associated with climate change, such as increased salinity resulting from sea-level rise and longer intervals between winter freezes, which can kill cold-intolerant mangrove species.

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.

Wetlands have the potential to absorb large amounts of carbon dioxide via photosynthesis, and flooded soils have low oxygen levels which decrease rates of decomposition to promote the retention of soil carbon. However, the type of greenhouse gases emitted from wetlands varies by wetland type and soil condition. A suite of approaches are being used to assess fluxes of greenhouses gases, like...

USGS investigates the eco-physiological responses of coastal forested wetland vegetation to envrionmental stressors, and what role vegetation may have in affecting local hydrological cycling as a result of these stressors.

As tidal freshwater forested wetlands - TFFWs - are influenced by salinty due to salt water intrusion, they may experience changes in plant community composition, growth, and productivity. Models are needed to predict vegetation community change or dieback, as well as changes in carbon sequestration and storage due to changing climate, drought, changes in freshwater discharge, elevated carbon...

Tidal freshwater forested wetlands - TFFWs - can be found in the upper intertidal areas of many estuaries and act as a transition between coastal marshes and bottomland hardwood wetlands. However, it is because of their location that makes them vulnerable to sea-level rise, and they are constantly transitioning to different wetland types. USGS addresses how various processes are affected in TFFWs...

Wetlands in river deltas - like the Mississippi River Delta Plain - may be more vulnerable to sea-level rise. Historically, coastal wetlands responded to these changes by increasing surface elevation or migrating up-slope. USGS conducts research to identify the biogeochemical influences on sediment addition in coastal wetland areas.

Sudden Marsh Dieback - SMD - has been documented for the past two decades throughout coastal areas of the United States. With these large-scale diebacks comes the loss of ecosystem functions and services. USGS scientsts use field work and greenhouse studies to investigate the factors that control the resilience and resistance of coastal salt marshes to SMD.

When it comes to hurricanes, wind and storm surge effect vegetation differently. USGS anlyzes these differences following Hurricane Sandy to help inform management on storm mitigation and long-term planning.

Understanding systems sometimes requires approaches that allow for both the discovery of the a system's structure and the estimation of its implications. Structural Equation Modeling - SEM - is one tool scientists use to better understand the complex world in which we live.

Mangroves will compete with salt marsh plants in transitional areas, and recent studies have documented the expansion of mangroves into marsh habitats. To better understand the plant community dynamics in this transition zone, USGS scientists are tracking vegeation changes over time in south Florida.

Wetlands vary in their abilities to keep up with sea-level rise; they either adjust vertically and/or move inland. USGS is working with partners around the world to measure rates of surface elevation change relative to local sea-level rise.