global mangrove alliance

How does pore water H2S affect mangrove restoration?

Abstract
Despite their critical importance and the numerous efforts to protect, conserve and restore mangrove forests, these ecosystems are still disappearing at worrying rates around the world. Alongside these losses, many restoration projects fail to achieve their target. This is often a consequence of ignoring why the natural recovery has not occurred in the first place. In this regard, hydrogen sulfide (H2S) and its typical rotten egg smell are omnipresent components in mangrove sediments. Nevertheless, too little attention has been given to its influence on the mangrove seedlings when transplanted to an area with a different sulfide concentration compared to their original habitat. Thus, this study aims to determine the sulfide tolerance of the red mangrove (Rhizophora mangle) and black mangrove (Avicennia germinans) using experimental nurseries in areas with high and low sulfides. The results reveal that high sulfide levels (> 20 mM) have serious effects on the growth of R. mangle, while having no significant effect on A. germinans, unveiling its ability to tolerate higher concentrations. Replanting A. germinans seedlings can facilitate success when restoring degraded and highly sulfidic areas. Additionally, this study provides a novel analysis of how microbial communities of the rhizosphere of A. germinans affect the survivability of mangrove seedlings in restoration projects.

Date
2023
Data type
Research report
Theme
Research and monitoring
Report number
University of Amsterdam - MSc Biological Sciences
Geographic location
Bonaire
Author

State of the World’s Mangroves 2021

The Global Mangrove Alliance’s recent report on the State of the World’s mangroves served as a call to action for mangrove conservation and restoration projects.  Although many of the trends centered around mangroves have looked bleak, new research shows that these areas are highly restorable meaning quick action can have significant, positive effects.

Global Mangroves

Mangroves are vital ecosystems providing coastal defense against sea level rise and worsening storms, creating critical habitats including nursery and breeding grounds, and can serve as carbon sinks making them a vital link in achieving net-zero carbon emissions by 2050.  It is estimated that nearly 15% of the world’s mangroves can be found between North and South America, mostly within the Caribbean. Unfortunately, many of the world’s mangroves have been lost or are severely degraded due to coastal development, the expansion of shrimp farming and human pollution.

Red Mangrove. Photo credit: Christian König

Luckily the Global Mangrove Alliance has been tracking the state of the world’s mangroves since it’s creation in 2018.  Through influencing local policies and public awareness on the importance of these habitats, there has already been some improvements in trends.  Overall, they found that the rate of mangrove loss has slowed worldwide since 2016. Furthermore, nearly 42% of all remaining mangroves are within protected areas. A number of recent projects have also demonstrated that mangrove area loss is highly restorable, meaning it’s not too late to save these critical ecosystems.

Dutch Caribbean Mangroves

Within the Dutch Caribbean, four of the islands have mangrove forests: St. Maarten, Aruba, Curacao, and Bonaire.  Of these, Bonaire has the largest of the mangrove forests, of which, nearly all fall within the designated National Marine Park. STINAPA along with other local NGOs have been diligently working to restore these mangrove areas. In fact, one of these restoration projects recently received international recognition with an IUCN BEST 2.0+ grant which funds restoration, reforestation, and scientific monitoring efforts on Bonaire through February 2023.  Additionally, groups such as the Mangrove Maniacs dedicate countless volunteer hours maintaining important water circulation channels to ensure the mangroves of Lac Bay stay healthy and thriving.

Call to Action

Red Mangrove. Photo credit: Marjolijn Lopes Cardozo

There is an urgent need to understand the extent of local mangrove areas and preserve and restore where possible. Governments need to include mangrove management into policy and planning. The private sector can benefit by recognizing mangroves as an investment opportunity, through options such as carbon markets, blue bonds and insurance-based investments. NGO’s and local groups can work to increase awareness and spearhead projects.  Academia and research communities can prioritize projects which help improve available data and modeling tools. Lastly, you, the individual can be involved by advocating for mangroves by spreading knowledge and looking for opportunities to get involved.

Want to get involved?

This Sunday, October 3rd, the Mangrove Maniacs of Bonaire will be hosting a mangrove outplanting event.  Volunteers will be planting mangroves along the southern coast to increase the natural mangrove fringing forest of this area.  These fringing forests are vital for minimizing coastal erosion and serving to protect this area from increased storm activity. Learn more by following along on the Mangrove Maniacs’ Facebook page.

You can find a link to the full State of the World’s Mangroves using the DCBD button below.

https://www.dcbd.nl/document/state-worlds-mangroves-2021

 

Article published in BioNews 47

 

Date
2021
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
St. Maarten
Author