| [Image: A recent Marsh Maneuvers camp] | | | | | | | |
The LSU AgCenter brings its considerable expertise in plant breeding and other traditional areas of research to address wetland loss.
Since the 1930s, about 1,900 square miles, or almost 1 million acres, of wetlands along Louisiana’s coast have been lost. This loss continues at the rate of about 30 square miles per year. Factors that cause this relentless erosion of one of America’s most valuable resources include the Mississippi River levee system that prevents sediments and nutrients from replenishing adjacent marshes, subsidence from compaction and sinking of soft marsh soils, and saltwater intrusion that kills vegetation.
The ramifications of this land loss are huge – not only for Louisiana but for the nation. Here are some facts from the Council for a Better Louisiana:
- Thirty percent of all U.S. coastal marsh is in Louisiana.
- Ninety percent of the coastal wetland loss in the lower 48 states occurs in Louisiana.
- Ninety-five percent of marine species in the Gulf of Mexico spend all or part of their lifecycle in Louisiana wetlands.
- Louisiana’s coastal wetland provides habitat for more than 5 million waterfowl and is home to more than 70 rare, threatened and endangered species and America’s largest wintering habitat for migratory waterfowl and songbirds.
- More than 30 percent of the nation’s commercial fishery catch comes from Louisiana coastal areas.
- More than 25 percent of oil and gas consumed in the nation travels through Louisiana wetlands.
One line of defense to prevent further land loss is to improve native marsh plants – to help them proliferate and do what they have done for thousands of years – hold onto land and keep it from washing out to sea. And that is where the LSU AgCenter plays a significant role. Nearly 10 years ago, LSU AgCenter researchers began a concerted effort to do for wetland plants what they have been doing for agricultural crops for decades – develop new varieties and more efficient management techniques.
“We use our expertise in plant breeding to develop plants and improve coastal habitats with the goals of restoration and reclamation,” said David Boethel, LSU AgCenter vice chancellor and director of the Louisiana Agricultural Experiment Station.
The principal plant targeted has been Spartina alterniflora, known as smooth cordgrass. This plant tolerates a wide range of salinity and can readily be produced in freshwater ponds. It is an ideal species for coastal reclamation work because of its stress tolerance and rapid growth. A single plant can grow to a clump of several feet in diameter within a year. It spreads underground and its dense canopy provides a significant buffer against wave energy. It grows parallel to the shore in water up to 18 inches deep.
“Spartina is very productive and very adaptable,” said Steve Harrison, plant breeder in the School of Plant, Environmental & Soil Sciences.
Other plants being studied include sea oats and bulwhip, which have some of the same characteristics as smooth cordgrass. Read the article on sea oats and on plant diversity.
The challenge in trying to populate barren areas with these plants is that they are not good at producing seed – unlike agricultural crops. And coastal restoration requires massive quantities of seed – good quality, viable seed.
AgCenter researchers have several projects under way to solve this problem. In the breeding program they select individual plants that demonstrate superior seed characteristics and use techniques such as selective crossing and tissue culture to develop improved lines. It is likely the AgCenter will release three new varieties of coastal plants later in 2007 – a smooth cordgrass line, a bulwhip and a sea oats variety.
Other problems with smooth cordgrass seed include dormancy and a tendency to die when dry. An AgCenter research project focuses on understanding these two traits and using this information to allow large-scale stand establishment of smooth cordgrass from seeds. Read more.
Another research team is working on diseases that affect smooth cordgrass.Read more. The severe brown marsh dieback along the coast in 2000 was caused in part by disease. Read the article about how researchers used small dredge sediment enrichment to restore brown marsh sites.
Acceleration of plant production requires fast seeding and efficient harvesting. AgCenter scientists have been successful in adapting aerial seeding – as is done in rice production, for example – for smooth cordgrass plots. Harvesting, however, still must be done by hand. But the plant breeders and engineers are trying to adapt some type of harvester that can maneuver on soft soil and mechanically remove the seeds.
Much of the initial research on coastal plants was conducted with the U.S. Department of Agriculture’s Natural Resources Conservation Service, and collaboration with this agency continues. The NRCS operates a 93-acre plant materials research center at Golden Meadow, which is about 20 miles southeast of Houma.
The AgCenter conducts coastal plants research in the Department of Plant Pathology & Crop Physiology, the School of Plant, Environmental & Soil Sciences and at the Rice Research Station in Crowley. Other units that contribute include the Department of Biological & Agricultural Engineering and the Department of Agricultural Economics & Agribusiness.
Scientists have research plots at the Central Research Station south of the LSU campus. Additional research areas and greenhouses will be constructed as part of the master plan for renovations and expansion at the Central Station and Aquaculture Research Station, also south of campus.
Much of this research activity will move over the next couple of years to the Coastal Area Research Station, formerly known as the Citrus Research Station. This is the AgCenter’s station in Plaquemines Parish – a parish that extends the farthest out into the Gulf of Mexico. Hurricane Katrina destroyed much of the station in 2005. The master plan for the new station includes new facilities and five ponds for plant research. Read more about the new station.
“We had already planned to make this change before Katrina,” Boethel said. “The hurricane’s destruction accelerated our plans. The focus of the research conducted at the site will change, but our commitment to that region of the state will remain.”
Louisiana’s wetlands are not only essential to the ecosystem but also to national security. Saving and restoring them requires many different entities bringing together their expertise and building upon each other’s knowledge. The LSU AgCenter has committed significant resources to this effort and has made important contributions – and will continue to do so well into the future. The articles in this magazine provide a look at some of the accomplishments.
Linda Foster Benedict
(This article was published in the spring 2007 issue of Louisiana Agriculture.) |