Marshes

While the historic focus of vegetation condition is the bulk live and dead compositions, these variables provide no information on the structure of vegetation (density and orientation). Canopy structure information is critical for monitoring status and trends, and essential in climate, weather, and ecological studies.

At the poleward marsh-mangrove ecotone, mangrove abundance and coverage is winter temperature-sensitive in that it oscillates in response to the frequency, duration, and/or intensity of extreme winter temperatures. Future winter climate change is expected to facilitate poleward mangrove range expansion at the expense of salt marshes in Texas, Louisiana, and parts of Florida.

At the global-scale, macroclimatic drivers govern ecosystem structure and function in tidal saline wetlands (e.g., salt marshes, mangrove forests, salt flats). However, global reviews and models for these ecosystems typically do not directly include climatic drivers. The objective of this research is to examine and forecast the effects of macroclimatic drivers on wetland ecosystem structure and...

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...

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.

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.

Will wetland vertical accretion rates be enough to keep up with the predicted rates of sea level rise? USGS looks at soil properties and geochronology in Louisiana wetlands.

Sediment deposition serves an important role in the long-term maintenance of coastal marshes. USGS investigates the mechanisms of coastal marsh elevation regulation to help predict marsh sediment requirements under various sea level rise scenarios.

Remote sensing helps USGS scientists detect and map surface oil in coastal environments.

With the help of remote sensing, USGS maps the progression of marsh dieback along the Louisiana coast.