Executive Summary (PDF 6.44 MB)
Dieback of Large Expanses of Salt Marsh Grass in
The browning and dieback of over 100,000 acres of smooth cordgrass (Spartina
alterniflora) served as a dire call to action for Louisiana's coastal
science community. This 6-part series explores the response to that
call, from satellite imagery to laboratory studies of individual plants.
Spartina alterniflora, also known as smooth cordgrass or oyster
grass, dominates regularly flooded saline marshes along the Gulf of
Mexico and the eastern United States coastline. This highly productive
ecosystem provides critical habitat and nutrition for many avian, fish,
and invertebrate species. In the spring of 2000, fishermen and scientists
noticed that certain areas of coastal marsh in south Louisiana were
turning brown. While patchy areas of dieback have been noticed in the
past, the size of the current dieback area is unprecedented. The areas
most affected are the salt marshes between the Mississippi and Atchafalaya
Since the initial site visits in the early summer, the area of the
marsh dieback has increased, and little recovery has been noted in affected
areas. Inspections of
roots and rhizomes indicate that this event is not simply a
dieback of aboveground plant material but can also result in death of
belowground portions of the grass.
Brown Marsh Action
Although we currently do not know the cause of the marsh dieback, scientists
believe it is related to a combination of stressors such as prolonged
drought conditions and other unknown biological or environmental factors.
A working group of resource managers and scientists has been established
to address the problem of the marsh dieback. Field sites have been set
up to test an array of biological, chemical, soil, and water parameters;
satellite and aerial imagery is being acquired; and the Governors
Office is coordinating ongoing state and academic research efforts with
federal efforts involving the CWPPRA Task Force and other coastal agencies
Dead and dying
marsh as seen from an airplane. Dark green areas in the back are
healthy black mangroves.
Brown Marsh Response Effort
Congress has allocated approximately three million
dollars for brown marsh research through the National Oceanic & Atmospheric
Administration to the Louisiana Department of Natural Resources (LDNR).
The Scientific-Technical Committee of the Barataria-Terrebonne National
Estuary Program and LDNR awarded funding for tasks
in five categories. Research projects began in April 2001 and will
conclude in the fall of 2002. Researchers will submit quarterly progress
reports to document data collection efforts. Aerial
and ground surveys of brown marsh areas have been conducted, and additional
reports are expected in August/September 2001.