Five Things to Know About the Mangrove Die-back in The Marls (At this point, anyway)

1. This die-back appears to be the result of multiple stressors acting together. Think of it in the sense of our own body- when our immune system is down, we are often more susceptible to getting sick. The same thing is likely happening to the mangroves.

2. It appears as though a fungal disease may be taking advantage of already stressed mangroves and causing die-back. We did preliminary surveys across Abaco and found fungal lesions nearly everywhere. However, the fungus was present in different densities in different areas. In the die-back area nearly all the leaves remaining on trees have lesions. We think that this pathogen capitalized on the mangroves being weakened by other stressors such as hurricanes, which cause extensive leaf drop, change in the movement of water, change in sedimentation and erosion.

3. We are still working on identifying the pathogen associated with the lesions we’ve found. We are confident that it is a fungus and are currently growing fungal cultures in the lab to examine defining morphological characteristics in addition to using DNA sequencing to identify the culprit.

4. We have documented the presence of the Robust Bush Cricket (Tafalisca eleuthera) in the die-back areas as well as other areas with high densities of lesions. These crickets are documented to consume Red and White mangrove leaves. As such, we were concerned about their potential role in die-back. We set out a caging experiment to exclude the crickets from certain dwarf Red mangrove trees to see just how much grazing they may be doing in the die-back area. This experiment is ongoing.

5. The take home: there is likely more than one causal agent of the die-back in The Marls. Many factors govern mangrove productivity and functioning: nutrient availability, salinity, sedimentation rate, herbivory, and disease are just a few of the factors that contribute to overall mangrove function making it very difficult to pin point which factors may be driving the die-off. On the bright side, we are confident that we have a lead on the causes and we are working hard in the field and laboratory to fully understand what is going on in The Marls.

By | 2015-09-28T11:44:06+00:00 August 26th, 2015|Categories: Featured, Mangroves and Creeks, The Marls|4 Comments

About the Author:

Ryann Rossi
My general research interests lie in the ecology of marine coastal ecosystems. I am most interested in the role plant diseases have in shaping the ecology of coastal and estuarine environments. I am currently studying the role of a plant pathogen in a die-off of Red Mangroves in The Bahamas. Follow Ryann Rossi


  1. Bob Koury August 26, 2015 at 5:22 pm

    My goodness, what a wonderful contribution you and your team are making.
    Not many things more important for the health of the Bahamas, and all costal areas, than a healthy mangrove community.
    Thank you for sharing your progress and knowledge.
    Rob Koury

  2. Rolling Harbour August 27, 2015 at 12:35 pm

    Great summary of the current state of play, Ryann, and many thanks for use permission at RH HQ!

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