Brown Marsh Home Brown Marsh Home
clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel clear pixel
banner banner
banner banner banner banner banner banner banner banner banner banner banner banner banner clear pixel
banner banner banner clear pixel
banner banner banner clear pixel
banner clear pixel
banner banner clear pixel
banner clear pixel
banner banner banner clear pixel
banner clear pixel

August 17, 2000 Minutes

August 22, 2000

To: Attendees of Spartina Marsh Dieback Scoping Meeting

Held at Nelson Memorial, LSU, August 17, 2000

From: Paul Coreil (LSU AgCenter) and Mike Materne (USDA-NRCS)

Re: Meeting notes

Thank you for attending the August 17th meeting on Spartina marsh dieback held at Nelson Memorial. We appreciate your interest and participation and we look forward to working jointly with each of you as we address this critical issue.   We wish to thank Carrie Borel and Quin Kinler for helping out during the meeting and Rex Caffey for his assistance in compiling the meeting notes.

A summary of the presentations and discussion from the meeting is provided below. This information is not intended as a formal transcript and we welcome your input on any items that we may have overlooked.

Notes of August 17, 2000 Spartina Marsh Dieback Meeting

The meeting began at 9:00 am with brief remarks by Don Gohmert (NRCS), Jack Caldwell (LDNR) and Bill Richardson (LSU AgCenter). The common point of these opening comments was the need to identify opportunities for agency partnering in our efforts to address this issue.

As facilitator, Paul Coreil (LSU AgCenter) then provided some comments on meeting protocol and suggested that a partnership approach must include private landowners and land managers, whose property is most affected by this problem. He challenged the group to use the meeting to identify the problem’s causes and extent of impact and to identify a logical course of collaborative research and action.

The first half of the meeting included technical presentations from various researchers. The following is a synopsis of the main points from each speaker.

Irv Mendelssohn (Wetland Biogeochemistry Institute, LSU)
Historical Aspects of Marsh Dieback in Louisiana

It is important to delineate wetland loss and plant dieback as 2 different things. Dieback of vegetation can occur without necessarily causing wetland loss. Spartina alterniflora (smooth cordgrass) marsh frequently has large areas of standing dead stubble.

Dieback is not a recent discovery but has been long recognized, especially in Louisiana, with publications on the subject dating back to the 1970’s.

Smith (1970) cited possible causes for smooth cordgrass dieback, including:

  • changes in salinity regime
  • pathogenic organisms
  • Iron (Fe) reduction and subsequent sulfide toxicity
  • changes in tidal regime
  • pollutants

A symposium on wetland plant dieback was sponsored by LSU in 1990 at an Ecological Congress in Japan. The consensus of the symposium was that multiple stressors are involved and that interaction of these stressors was a significant factor.

Approximately 90% of dieback is a result of a natural degradation process of interior marsh. Vegetation on the edge of waterways is typically more healthy due to a greater amount of soil accretion and oxidation. However, interior marsh soils often lack adequate accretion, and thus exhibit a lower redox potential, Eh (less oxidized, more reduced) as they become waterlogged/submerged. This leads to dieback and if vegetative residue is unable to contain the soil, erosion can lead to increasing areas of open water.

In these interior areas of marsh, the vertical accretion rate cannot keep up with sea level rise and thus more dieback occurs. In situ decomposition of this vegetation can exacerbate the demand for oxygen, and cause sulfate (SO4) to reduce to hydrogen sulfide (H2S). This is all part of a natural deltaic cycle.

Some findings related to marsh type:
In salt marsh, dieback is usually not due to salinity (salt-water intrusion) and is more related to submergence of the vegetation for prolonged periods. In brackish marshes, dieback can be caused by saltwater intrusion and this can be exacerbated by submergence.

Factors determining/influencing dieback:

  • marsh type
  • species composition
  • intensity of stressor
  • duration of stressor
  • interactions with other abiotic stressors
  • biotic modulators (pathogens, herbivores, etc.)
  • pre-stressed stability


  • Salt marsh dieback not new in LA, studied since 1970’s
  • However, recent incidents are unique because we are seeing a very widespread case over a very short period of time.

Karen McKee (USGS National Wetland Research Center)
“Potential Causes of Spartina Marsh Dieback”

(Slides of dead/dying smooth cordgrass marsh) Potential causes of dieback

Chemical/Petroleum Spills – there has been no evidence to support that chemical/petroleum spills are involved in this situation. The symptoms of this dieback are too widespread. However, cursory examination of this factor should be undertaken to completely rule out this as a cause.

Pests/Pathogens – preliminary tests have not found a widespread pest or pathogen that has yet to be associated with this occurrence of dieback. However, pathologic examination should/will continue.

Soil Phytotoxins – derivatives of rotting/fermented organic matter (acids, sulfides, etc.) can increase soil oxygen demand and stress vegetation. However, their initial contribution is difficult to isolate because they are naturally occurring byproducts of decomposing vegetation regardless of the initial cause. Their presence can actually exacerbate the toxicity of the growing conditions. Research is ongoing to characterize soil conditions in which soil phytotoxins are formed and persist.

Climate Extremes – climatic extremes can have significant impact on growing conditions and ultimately plant health. For example the recent drought may have greatly increased salinity levels beyond anything witnessed in years passed. However, research is needed to compare the climatic data of the past few years with historical climatic data for the region.

Low Genetic Diversity – as genetic diversity increases, ecological amplitude increases.  Changes in environmental conditions may alter a population to favor particular species strains/individuals. Research with the marsh reed Phragmites australis has shown 2 genetically distinct populations, one of which is susceptible to certain environmental factors.

Interaction of Environmental and Biotic factors – multiple factors have been implicated in dieback; however the interaction of these factors together needs to be researched more to determine how significant their interaction has been as a cause of dieback.

Ed Profit (USGS National Wetlands Research Center)

Aerial surveys have been conducted using NWRC aircraft; aerial photography is being collected for certain areas.

Physiochemical conditions have been recorded at various sites affected by dieback.

Southern Erosion Table (SET) data is being used to analyze erosion rates at a specific site(s).

Above and below ground dieback/viability is now being sampled at many sites.

DNA sampling is being conducted with surviving plants to characterize resistance.

One preliminary experiment is using vegetative samples from affected and non-affected areas to determine if recovery will occur under ideal growing conditions simulated in lab.

Samples are being analyzed for pathogens. Dead/dying plants are being tested to determine potential for dieback to spread to healthy specimens in lab conditions.

USGS NWRC sampling sites located at Bay Junop, Fouchon, and Bastian Bay. Sampling at these sites for H2S, Salinity, DO, Eh, pH, water depth, etc… and some quantitative sampling. NWRC is initiating research teams to address causes and consequences.

NWRC research objectives

  • survey spatial extent and severity of damage
  • determine causes
  • evaluate ecological consequences
  • map extent and rate of change
  • map above and below ground dieback
  • use field studies

Potential causes:

pathogens, spills, natural stressors (biotic/abiotic), and interactions.

Remedial efforts should be based on scientific studies with periodic data review (monthly?) to contribute to and refine restoration recommendations. Trials are warranted to consider alternative actions (e.g. plantings/seeding).

Kerry St. Pe (Barataria-Terrebonne National Estuary Program)

A recently shot video of coastal marsh dieback was shown. The footage showed extensive areas of dieback indicated by brown and black marsh from the Terrebonne coast eastward to Barataria. Black areas were identified as those where vegetation had completely degraded leaving only stubble and marsh soils. Mississippi delta footage in Plaquemines Parish east of Empire was noticeably more healthy in comparison to the marshes to the west.

Gary Breitenbeck (Department of Agronomy, LSU Agricultural Center)
A “Newcomers” Perspective

Samples of smooth cordgrass were taken from lower Barataria Bay around Grand Terre.

Visible signs of dieback exhibit a “wave” pattern known as “scorching” in agriculture. Samples were analyzed for pathogenic aspects associated with scorching in agronomic plants.

Clearly an environmental effect. Low and high areas appear to be affected, with randomly distributed symptoms.

Drought conditions in the region are beyond extreme; they are classified as exceptional.

Three areas were analyzed and samples were taken from dieback areas and adjacent non-dieback area (however, more appropriately should be called post and pre dieback, respectively since adjacent areas have subsequently succumb to dieback)

Plants, roots, and shoots were sampled. The following data was recorded.

Parameter units Pre Post

Total Nitrogen % 0.46 0.57
Organic Carbon % 6.51 6.77
C/N ratio 14.2   11.2
Ammonia mg/kg 1.3 0.7
Nitrate mg/kg 5.4 12.8
Phosphorus mg/kg 437 537
Iron mg/kg 9747 871
Sulfur mg/kg 10746 745
Ec (salinity) 35.4 35.8
Sodium 28.3 25.3

Bar graphs of data illustrate elevated Na, S, and N uptake in post-dieback samples of shoots and roots.

Tidal flushing may be mitigating the problems associated with in situ decomposition. Fat and abundant crabs are consistent with extra transport of detritus through the system.

Hypothesis: marsh is dying due to a cascading environmental collapse induced by salt stress combined with biotic factors, which is temporary in nature.

Dieback areas can recover – but only if the soil substrate is not lost to erosion in the interim. Once it converts to open water it’s too late. A hurricane or winter storm could be devastating.

The second half of the meeting included an open discussion of causes and extent of dieback and focused on required research and courses of action needed to address the problem. In some cases, names are listed after specific comments.

Have we considered the effect of tides? Are they exacerbating the phenomena? We should consider extended periods of salinity as compared to previous years? (Jack Caldwell)

What existing monitoring data is available for consideration? Is there a clearinghouse (list of people) for this type of information? An email group from the sign-in of this meeting would be a good start.

Centralized website(s) should be identified for dissemination of this information with slide presentations included.

In the next 60 to 90 days we should strive to have an interim assessment by a team to develop a consensus on relevant parameters and to report back to this group on the causes, severity/extent, next steps and pilot projects (Dave Fruge).

The Chenier Plain should be a focus also when we document the extent of this crisis. There has also been dieback with Spartina patens (wiregrass) (Andy N.)

Documenting the geographic extent above and below ground will require expanded agency efforts. (Bob S.)

The Gov’s Office of Coastal Activities has a meeting on this issue scheduled for September 14th.A 60 to 90 day period will coincide with the remainder of this growing season and we need to begin identifying critical short-term opportunities for research. There are some things that can be done now (Bill Good).

The assessment team needs to be multi-agency, multi-disciplinary.

Are there specific remediation efforts that we can think of now such as edge protection (Paul Kemp)?

Critical edge must be protected by some temporary or long-term measure. Perhaps marine advisories to slow traffic and reduce boat wakes (Gary B.)

What about mangroves as a stopgap measure?

There are some long-term freeze susceptibility concerns with black mangroves and any seedlings would not be available until September (Karen McKee)

Plant materials for restoration are already in very short supply – this will be a constraint for this growing season. The NRCS plant material center has many plants (140 ecotypes) currently available that could possibly be directed at critical areas. The commercial industry would need to be considered. Need to accelerate contract process to encourage production of plant materials for restoration/critical needs (Mike Materne).

Solving the problem in this growing season is unlikely.

We need to form a multi-agency working group to allocate tasks, identify funding sources, and document the extent of the problem. The group could meet again once the working group has convened and produced a summary (Jack Caldwell).

We need to consider short-term and long-term goals in a phased-in approach and identify concurrent/parallel research initiatives. Is there something CWPPRA can do to support this working group and their research (Don Gomert)?

We should also be studying the areas that do not appear to be affected such as Southeast of Caernarvon and Batiste Colette – what are we doing different in those areas (Mark Schexnayder).

The Gov’s Office of Coastal Activities meeting is on the 14th of September and that would be a logical point for a follow-up for the working group (Cynthia Taylor).

The working group will need to be formed before September 14th. How can BTNEP help to expedite/facilitate the effort?

We may need an interim meeting before the 14th to be sure that all stakeholders can help contribute to this effort and the working groups (Karen Gautreaux).

Prevention is cheaper than restoration. Can we capitalize on existing equipment and resources – what about using on-site dredges for strategic spoil placement?

What about flown-in or boat application of inorganic fertilizer for edge vegetation in critical areas (Mark Schexnayder)?

The extent of the affected area may be too large for such an approach. First we need to delineate the extent and pattern of the dieback so that we can target critical areas better. Second we need to develop a consensus on cause(s). Thirdly we need to characterize the dynamics of the problem – is it expanding, retracting, or static. Fourth, we need to identify and pursue remediation alternatives for critical areas (Irv M).

We also need to estimate the cumulative/long term effects of the worst case scenario – if there is no recovery what are the biological and economic risks/implications (Bill Good).

The LDNR will work with the Gov’s Office to help coordinate the establishment of a working group (Jack Caldwell).

The Governor recognizes how critical this issue is and the Office of Coastal Activities will cooperate with LDNR to form the working group (Karen Gautreaux).

Fly-overs by our company confirm what has been shown in the presentations today. We are very concerned and we will help to address this issue. Could higher temperature or water levels (e.g. The Atchafalaya) be somehow related? In the short run, the dieback means less land revenue to private landowners because of diminished resources (trapping, hunting, etc.) but in the long run it will translate to loss of land, title, and tax revenues as it converts to open water (Frank Ellender).

Most dieback that we have observed is not as bad in the fresh/intermediate marsh as in the salt marsh. Drought effects such as cracked soils have been observed in some areas, which have become inaccessible. Other species are showing drought stress as well – including wiregrass, bulwhip, and even tallow trees (Tim A).

At Rockefeller refuge we had no major symptoms in my research plots in March 1999 – now the area is seeing major problems with dieback. Especially noticeable with wiregrass.  Healthy above ground marsh can have little below ground biomass – we need to define what is “healthy marsh” (John Foret).

The CWPPRA Technical Committee will meet in September to develop a position on this issue. It would be good to have some of this research provided. There is only $5 million in planning dollars at our discretion so other funding sources need to be identified (Tom Podany).

What I am hearing is that we need to move quickly on this issue and develop a working group with the appropriate expertise and to identify some items of short term action that can be addressed such as test/trials and protection. The long term will require more research to find the proper solution (Paul Coreil).

What is needed here is a good set of baseline monitoring data for comparison – but that doesn’t exist. This should be a wake-up call for the need to develop and maintain a coast-wide data monitoring system (Andy Nyman).

What will be the public education component of this initiative? What can be done to provide consistent, relevant, and factual information on this issue to the public? There are several avenues for this type of outreach – BTNEP, Cooperative Extension, CZM (Paul Kemp).

There is also an upcoming meeting of the Coalition to Restore Coastal LA that would benefit from having some of these presentations made.

It would be good also to have some of this basic information presented at the upcoming CWPPRA meeting on next Tuesday the 22nd at LDWF (Tom Podany).

The Gulf of Mexico Program has and will continue to be involved.

BTNEP has a management conference on September 13th and we would like to see some information presented on the dieback issue. BTNEP can serve a coordination role but our staff is currently overburdened so we would utilize your collective expertise (Kerry St. Pe).

BTNEP’s involvement as a mediator/participant would be beneficial; however, Len Bahr, with the La Gov’s Office of Coastal Activities, has been appointed point person on this issue by Gov. Foster.

What are the critical assessment needs/research needs?

We need to research what has happened and concurrently document to what extent it has happened.

Aerial photography is a short term objective. NWRC is planning more fly-overs for the 1st - 2nd week of September, clouds permitting.

The NWRC flights are not coast-wide, but in pre-designated areas (Jimmy Johnson).

Cost for fly-overs would be $14K for small areas but $45 K would be needed for entire area at 1:24K resolution.

NWRC, Wetland Biogeochemistry, and the AgCenter are already preliminarily examining samples.

Need to move towards a consensus on the causes and ecological consequences.

Need to document what other species are being affected – there is some browning of wiregrass and Distichlis spicata in Barataria (Greg Linscomb).

The level of this problem constitutes a challenge to scientists to step up and volunteer their time and effort.

We need a renewed emphasis on restoration technology such as mechanized planting (Gary B.).

Can we estimate the extent of impact using area extrapolation from aerial photos? GIS mapped transects info could be overlaid onto soil or vegetative profile maps (Michot, Linscomb, Chabreck, Mendelssohn).

A sampling subset of impacted sites may be financed by LA Sea Grant funds allocated for marsh flights.

Disciplines/tools/agencies needed to address the issue include ecology, botany, plant pathology, agronomy, genetics, biogeochemistry, geology, soil science, coastal engineering, resource economics, land managers, and resource agencies.

Does this warrant an official “Emergency Situation” by Governor Foster? Could this lead to additional funding from FEMA beyond CWPPRA funding?The working group will need to formalize a proposal for this initiative with a detailed budget and do so very soon.

The LA Coast, BTNEP, and LDNR websites could be the clearing-house for collection and dissemination of information (Jimmy J.)

The CWPPRA Outreach Committee could develop a layman presentation/news release on the issue and make it available on the website along with other information (Beverly Ethridge).

The meeting adjourned at 12:30

left corner Related Sites right corner

Privacy Accessibility FOIA Disclaimer