Climate change

An Assessment of the Impacts of Climate Change on Coastal Inundation on Bonaire

Part of the larger The impacts of climate change on Bonaire (2022-present) report available here - https://www.dcbd.nl/document/impacts-climate-change-bonaire-2022-present

 

Summary

Bonaire is as a small and low-lying island state vulnerable to the impacts of climate change. In the future decades, sea level rise and tropical cyclones are expected to increase coastal flood risk on the island. Yet, it is still unknown to what extent coastal flooding will increase and which areas on Bonaire are expected to flood. Therefore, this study aims to assess the impacts of climate change on coastal inundation on Bonaire. First, a static bathtub model is used to estimate the future coastlines of the island under multiple sea level rise projections. Second, the SFINCS model is applied to incorporate the dynamic storm components of storm tide and waves in addition to sea level rise. The results of the inundation models indicate that coastal inundation becomes critical for large parts of Kralendijk in 2150 under scenarios SSP5-8.5 and SSP5-8.5 LC. Under the more optimistic scenarios SSP1-2.6 and SSP2-4.5 coastal inundation remains limited to the nature reserves of Klein Bonaire, Lac Bay and the saliñas. Therefore, the results of this study indicate the importance for Bonaire of globally limiting climate change to a lower-end future climate scenario.

Date
2022
Data type
Research report
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire

The Impacts of Climate Change on Bonaire - Synthesis Report

Part of the larger report available here.

 

Executive summary

Small islands are particularly vulnerable to climate change because of their fragile ecosystems, small economies, and often extensive, low-lying coastal areas. Therefore, small islands, such as present in the Caribbean Netherlands, are expected to suffer excessively from rising temperatures, changes in precipitation, sea-level rise, coral bleaching, cyclones, droughts and floods. Despite this widespread conviction, scientific evidence of these effects in the Caribbean Netherlands is scarce, and as a result, limited adaptation strategies are developed or implemented by local and Dutch governments. 

In this study, an analysis is conducted assessing the impacts of climate change for the island of Bonaire. Given the uncertainty regarding the actual level of climate change in the future, four universally recognised scenarios are simulated, ranging from an optimistic scenario “SSP1-1.9” (corresponding to a mean temperature rise of 1.4°C at the end of the 21st century relative to pre-industrial levels), which assumes climate change will  modestly increase relative to current levels, to a pessimistic scenario “SSP5-8.5” (corresponding to a mean temperature rise of 4.4°C at the end of the 21st century relative to pre-industrial levels), which suggests very high levels of climate change. Impacts are measured and reported at different moments in time, mainly looking at the years 2050 and 2150, representing short-term and long-term effects of climate change, respectively. A mix of methods from various scientific disciplines are used to estimate the impacts of climate change, including climate and flood models, ecological-economic models, as well as social-science methods such as social media analysis, participatory mapping and key-informant interviews. Although the subcomponents of the study are systematically aligned and integrated, four topics can be distinguished: the estimation of the biophysical impacts, the modelling of economic effects, the identification of socio-cultural effects, and the exploration for potential adaptation options. 

First, we analyse the expected bio-physical and environmental changes associated with different climate projections. The applied flood model simulations reveal that, already by 2050, sea-level rise will cause permanent inundation of parts of the low-lying nature reserves of the saliñas, Lac Bay and Klein Bonaire, thereby altering the extent and dynamics of these areas. Increasing storms are expected to double this inundated area, with an estimated surface of around 8 km2 comprising both permanently and temporarily flooded areas. With climate change increasing over time, sea-level rise and coastal storm inundation will further expand the flooded surface area of Bonaire by 2150, ranging from 14.3 km2 to 32.2 km2, depending on the climate scenario. These flood simulations clearly identify Bonaire's high-risk built-up areas: Belnem and other areas in Kralendijk. But this is not the complete picture; coral reefs are extremely vulnerable to temperature increase, acidification and extreme storms, and our study predicts significant declines of the reef health index of the coral reefs of Bonaire in three of the four climate scenarios already by 2050. Since coral reefs currently act as a natural buffer against waves on Bonaire, the loss of this important ecosystem will further amplify the flooding caused by climate change. 

Second, we estimate the expected economic effects associated with climate change, including impacts on economic development, the built environment and infrastructure. The economic impact is mainly felt through damage costs caused by floods as well as negative effects on tourism caused by the loss of corals. Storms are expected to largely affect Kralendijk and Belnem under the worst climate scenario, resulting in estimated damage costs of US$317 million by 2050. Since permanently inundated buildings are not included in the damage costs projections, these costs are likely to be on the conservative side. As a large part of the damaged structures are in key areas, and numerous coastal and southern roads on the island will be unusable, flood hazards will not only disrupt entire neighbourhoods but also make it impossible for emergency services to reach these areas and buildings. Moreover, we estimate that the economy will be negatively affected by the loss of coral reefs since numerous valuable dive sites will be severely degraded. In the worst climate scenario, coral reef degradation may lead to a reduction of quality dive sites from 86 to 12 and a subsequent reduction in dive tourist arrivals of more than 100 thousand visitors by 2050, causing a contraction in Bonaire’s economy of roughly 25%.

Third, we identified the expected socio-cultural effects associated with the climate change in terms of loss of cultural heritage and health impacts. The tangible cultural impact is felt through the permanent flooding of key locations with cultural significance for Bonaireans, such as the slave huts and the house at Boca Slagbaai. Loss of cultural heritage may have severe impacts on society, as it may lead to a decline in cultural identity and social cohesion. The intangible cultural impact of extreme weather events and rising temperatures includes pressures on the traditional ways of life of Bonaire, including fishing, agriculture, and festivities. Additionally, numerous experts on Bonaire reported that the effects of climate change on Bonaireans’ health, such as changes in vector-borne disease incidence and heat-related stress, are already observed and are likely to increase with climate change. This impact is further magnified with the ageing of the population on Bonaire, making the people even more susceptible to heat-related stress disorders. 

Fourth, we evaluate several adaptation measures to understand which management alternatives Bonaire could implement to cope with the negative consequences of climate change. Potential adaptation strategies include nature-based solutions such as the conservation of coral reefs and the restoration of coastal vegetation, which contribute to the prevention of flooding. Moreover, decision-makers should consider investing in various heat mitigation strategies, such as climate-sensitive building designs, artificial and natural shading, as well as information programmes to educate the population on how to protect themselves from high-temperature exposure. We conclude that, although the impacts of climate change necessitate immediate action, decision-makers should also focus on the longer term, such as 2150 and beyond, as the effects of climate change will worsen significantly over time. 

Since our study did not address all effects of climate change and since climate research with regional and local precision is still in development, the impacts presented in our study can be regarded as preliminary lower-bound estimates. In other words, additional research may generate estimates of even more severe impacts of climate change in Bonaire. In addition, we like to emphasise that there is little knowledge about the effects of climate change in the Dutch Caribbean at the present time. This study is the first attempt to map and quantify a broad range of climate change effects for Bonaire, which is only one of the six islands in the Caribbean Netherlands. Because the research results are unique for Bonaire, we recommend conducting similar studies for the other Caribbean islands in the Kingdom of the Netherlands. 

 

Date
2022
Data type
Other resources
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire

The impacts of climate change on Bonaire (2022-present)

Small islands are particularly vulnerable to climate change because of their fragile ecosystems, small economies, and often extensive, low-lying coastal areas.

Therefore, small islands, such as present in the Caribbean Netherlands, are expected to suffer excessively from rising temperatures, changes in precipitation, sea level rise, coral bleaching, cyclones, droughts and floods. Yet, scientific evidence of these effects in the Caribbean Netherlands is scarce.

In this study, an analysis is conducted assessing the impacts of climate change for the island of Bonaire. A mix of methods is used to estimate the impacts of climate change, including climate and flood models, ecological-economic models, as well as social-science methods such as social media analysis and participatory mapping. Four sub-studies can be distinguished: the estimation of the biophysical impacts, the modelling of economic effects, the identification of socio-cultural effects, and the exploration for potential adaptation options.

The main findings of the study include the following:

  • Already by 2050, sea level rise will cause permanent inundation of parts of the low-lying nature reserves of the saliñas, Lac Bay and Klein Bonaire. The flooded surface area will increase further by 2150, threatening Bonaire's high-risk built-up areas such as Belnem and other areas in Kralendijk. The loss of coral reefs as a natural buffer will amplify these effects.
  • The economic impact of climate change is mainly felt through damage costs caused by floods as well as negative effects on tourism caused by the loss of corals. Storms and floods are expected to cause an estimated damage costs of US$317 million by 2050. The degradation of coral reefs leads to the degradation or loss of the majority of dive sites on Bonaire, which may cause a reduction in tourist arrivals of more than 100 thousand visitors.
  • Climate change is also expected to severely cause loss of cultural heritage and health impacts on Bonaire. Among others, this includes the permanent flooding of key locations with cultural significance for Bonaireans, such as the slave huts and the house at Boca Slagbaai. Additionally, climate change is expected to affect Bonaireans’ health, such as changes in vector-borne disease incidence and heat-related stress.
  • Potential adaptation strategies against climate change on Bonaire include nature-based solutions such as the conservation of coral reefs and the restoration of coastal vegetation, which contribute to the prevention of flooding. We conclude that, although the impacts of climate change necessitate immediate action, decision-makers should also focus on the longer term, such as 2150 and beyond, as the effects of climate change will worsen significantly over time.

For more information about the study or sub-studies, download the following reports:

Date
2022
Data type
Research report
Geographic location
Bonaire

Bonaire's Southern Wetlands Management Plan

EXECUTIVE SUMMARY

The southern wetlands of Bonaire represent a unique environment for the island. Consisting of a wide variety of habitat types including caves, karsts, dry tropical forests, coastal areas, salt pans and mangroves. The Ramsar site Pekelmeer lies completely in this area, as well as a small portion of the buffer zone of the Ramsar site Lac Bay.

Culturally, a number of Bonaire’s historic monuments and tributes to its past can be found as you drive around the perimeter, from ruins of old salt pans to the remains of slave huts and gravestones. Maintaining and respecting these sober reminders of Bonaire’s history is vital to ensuring the sacrifices of the enslaved populations are not forgotten. It would be impossible to separate the historic and cultural identity of Bonaire from this area.

Economically the southern wetlands represent commercial opportunities for salt extraction by Cargill Salt Works as well as a significant driver of tourism, whether it is history enthusiasts, cyclists, kiteboarders, recreational fishers, scuba divers or bird watchers.

The cultural and economic value of this area is only surpassed by its environmental value. The southern wetlands are recognized internationally as an Important Bird Area (IBA), as a site of regional importance by the Western Hemisphere Shorebird Reserve Network, as an area important for sea turtle nesting and as a Ramsar site. The Ramsar site Pekelmeer, which encompasses most of the southern portion of the wetlands, is critical to a number of threatened, endangered or keystone species. Pekelmeer offers a much-needed rest stop for a number of migratory bird species while also serving as an important breeding ground for the Caribbean Flamingo and five different tern species. Furthermore, the southern wetlands constitute most of the natural habitat of the rare and endemic Bonaire Sabal Palm.

This management plan offers a description of the southern wetlands (chapter 1), a legal and legislative overview (chapter 2), a description of resources and utilities (chapter 3), an explanation of the spatial development plan (chapter 4), an overview of conservation target habitats (chapter 5), an analysis of threats and issues (chapter 6), an outline of management actions and strategies (chapter 7), and provides recommendations for the management plan evaluation and review (chapter 8). Conserving this unique wetland will be a major challenge. A critical first step is to designate Pekelmeer as a protected area under island and national legislation, and appoint a management authority.

Date
2022
Data type
Research report
Theme
Governance
Education and outreach
Legislation
Research and monitoring
Geographic location
Bonaire

Dutch Caribbean Nature Alliance facilitates platform for investigation of marine protected areas in the Caribbean

Willemstad – The 2021 Dutch Caribbean Nature Alliance (DCNA) Convention began with a workshop on climate change resiliency. The workshop served as a platform for knowledge sharing between researchers from the Royal Netherlands Institute for Southeast Asian and Caribbean Studies (KITLV), and Dutch Caribbean experts. The participants discussed the impact of climate change on marine ecosystems in the Dutch Caribbean and related issues.

Different perspectives

This workshop is part of a pilot project that aims to unpack the impact of climate change on marine protected areas in Indonesia and the Caribbean. To get an accurate understanding of the key issues and challenges, listening to experts from various fields within and outside academia is key. Yvonne Kunz, main postdoctoral researcher at KITLV notes that “if we want to understand the impact of climate change on marine protected areas, we must engage with those who experience this impact firsthand. This is our main motivation to obtain information from as many sources as possible.”

Climate change resiliency workshop

Collaboration with DCNA

David Kloos, project lead at KITLV, further explains that “DCNA has been involved from the very beginning of this pilot project. They represent a key stakeholder in the Caribbean.” The project is a comparative analysis, and the stakeholders are taking care to ensure that crucial comparisons are made from various angles. Mr. Kloos says that “policy versus actual operations is one aspect, but also the number of years of existence of the marine protected areas. We have chosen to investigate protected areas in Aruba and Bonaire, where there is a difference in years of existence. By comparing Indonesia and the Caribbean, KITLV can analyze yet another aspect. Whereas in the Caribbean the need to protect marine areas takes on a ‘bottom-up’ approach, in Indonesia the initiatives are more government-led. In addition, these contrasts facilitate the comparison and analysis of different conservation narratives.”

Climate change impact

For some, climate change is seen as a theoretical issue, even though the Caribbean region has already started to experience its effects.

Melanie Meijer zu Schlochtern of DCNA states that “we have observed a deterioration of our coral reefs. The majority of our population may not be aware of this, but if we do not stop this decline, we can end up with green water, instead of the crystalline blue seas that we know today. If we can only become more aware of the economic value of these coral reefs, we will soon start to realize that further decline will have a direct negative impact on tourism, one of the main economic pillars of our islands.”

Everyone can and must contribute to mitigation of the impact of climate change.

This pilot project is being conducted in partnership with the Netherlands Institute for Ecology (NIOO), the Netherlands Institute for Advanced Studies (NIAS), and various partners in Indonesia and the Caribbean. More information about this pilot project and practical tips can be found on DCNA’s Facebook page: DutchCaribbeanNatureAlliance.

 

Article published in the Special Edition Bionews: 2021 DCNA Convention and BioNews 50

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

Bonaire Hosts an International Mangrove Restoration Workshop

Between October 25th and 28th, Bonaire’s Mangrove Maniacs hosted their first Mangrove Restoration Workshop .  The goal was to provide a platform for researchers, conservationists, park authorities or anyone passionate about nature restoration to share ideas and knowledge on mangrove restoration techniques.  With representatives from over 12 countries, including 20 in person and 40 virtual participants, this workshop strengthens the mangrove conservation network across the Caribbean.

Mangrove Restoration Workshop Presentations. Photo credit: Mangrove Maniacs

 

International Collaboration

Representatives from around the world including Aruba, Bonaire, Curaçao, the Bahamas, Jamaica, St. Lucia, Martinique, the Netherlands, Mexico, Belize, Costa Rica and the United States tuned in to share ideas for mangrove restoration practices.  Throughout this four-day event, participants engaged in meaningful dialogue, swapping ideas and tips on ways to maximize conservation efforts.  In addition, the last two days provided hands on experience in mangrove restoration, building and maintaining mangrove nurseries, as well as outplanting both along the coast and within degraded areas.

Funding and support was provided by the Regional Activity Centre for the Specially Protected Areas and Wildlife (CAR SPAW), Mangrove Maniacs, STINAPA Bonaire and the Dutch Caribbean Nature Alliance.  Presentations throughout the workshop spanned from expert University partners to representatives from NGOs to enthusiastic citizens.  In total, over 20 people were able to attend the workshop in person and over 40 participants logged in to attend the workshop virtually.

 

Lessons Learned

Participants in mangrove channel. Photo credit: Jessica Johnson

In addition to creating new networks and collaborative partnership opportunities, this workshop provided firsthand experience in the field of mangrove restoration.  Mangroves are continuing to gain recognition not only for their ability to provide critical habitats and coastal protection but also as a significant tool for building resilience against climate change.  This workshop provided key insight into the importance of maintaining environments to serve as carbon sinks as well as the ability to leverage Blue Carbon in future reporting and financing prospects.

DCNA’s director, Tadzio Bervoets, took the opportunity to stress the importance of supporting and growing research and education opportunities for students within the Caribbean region.  Caribbean islands have the unique ability to showcase a wide variety of natural habitats, perfect for conducting research and staying on the cutting edge of habitat restoration and conservation techniques.  Fostering this thirst for knowledge and educational growth within local Caribbean populations will be key to pushing the Caribbean to the forefront of environmental research.  Knowledge sharing opportunities, such as these, provide unique opportunities to bring together a wide range of people to maximize communal understanding of mangrove forests.  As climate change and human-driven pressures continue to increase, interventions from all levels will be required.

Members from Bonaire’s STINAPA and Aruba’s FPNA working together to plant buttonwood tree. Photo credit: Mangrove Maniacs

More Information

To learn more about the workshop, please visit the Mangrove Maniacs’ webpage (www.mangrovemaniacs.org/workshop2021).  From here you will find links to most of the presentations as well as contact information for presenting participants.  For more information on how you can get involved, contact your local park authority or join the Mangrove Maniacs mailing list by using this link.

 

Article published in BioNews 49

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

Dutch Caribbean Nature Alliance Paints Bleak Picture of the Impacts of Climate Change in the Dutch Caribbean

Concerned at Lack of Mention of the Impacts of Climate Change During Address of King Willem Alexander at the Joint Session of the States-General of the Netherlands

Increased rain runoff due to a changing climate has been impacting the coral reefs of the Dutch Caribbean, including the coral reefs of Bonaire. Source: Marcel van der Kamp

The Dutch Caribbean Nature Alliance expressed its concern at the lack of attention on matters related to the impact of Climate Change in the Dutch Caribbean in The Hague. Despite Dutch Prime Minister Mark Rutte mentioning the impacts of Climate Change in the Dutch Caribbean during his intervention at the UN General Assembly in September, very little concrete actions and support for what will be the most critical crises facing people of the Dutch Caribbean in the immediate future. The statements from the regional conservation network comes on the eve of the opening of CoP26 held in Glasgow, Scotland from November 1st to November 12th.

“While it was commendable that climate change has been mentioned by Dutch Politicians lately, we  are still quite concerned that very little attention is being paid to the impact climate change will have on the Caribbean part of the Kingdom, this while it is clear that those living in the Caribbean, the biodiversity hotspot of the Kingdom of the Netherlands, are at the forefront of the climate crises,” commented DCNA Director Tadzio Bervoets.

Bervoets continued to mention that during meetings held recently with various parliamentarians and directorates in the Netherlands, DCNA highlighted the existential crises posted by the changing climate; “We had to remind the politicians, bureaucrats and technocrats in The Hague that the various agreements and accords related to climate change are ratified by the Kingdom of the Netherlands and not by only the Netherlands, and as such there has to be increased focus in ensuring that the islands are better equipped to deal with what is expected to be an existential crises. We even had to explain issues such as increased hurricanes, coral bleaching, sargassum invasions and droughts to what we assumed would be experts in climate change who had no idea about these impacts. This is both disappointing and alarming,” continued Bervoets.

The most recent climate change predictions for the Caribbean region by the Intergovernmental Panel on Climate Change (IPCC) are alarming and suggest that the islands of the Dutch Caribbean will go through profound environmental changes within the next few decades. The IPCC has projected that for the Caribbean Region an increase in air temperature of 1.4°C will result in a decrease in rainfall of 5 to 6%; an increase in the frequency and intensity of extreme weather events including a 66% increase in hurricane intensity; and a rise in sea level of 0.5 to 0.6m as a result of thermal expansion of water and glacial melt.

In 2015 the Sint Maarten Nature Foundation conducted a study which modeled what the island will look like with just 1.5 meters of sea-level rise. Source: Sint Maarten Nature Foundation

 

These climate change predictions are especially worrying in the context of an already visible warming trend. Average temperatures in the Dutch Caribbean have risen steeply over the past 40 years according to recent data. In Curaçao, research carried out by the Meteorological Department found that over the past few decades the island has progressively experienced more hot days and fewer cooler nights. Because the islands of the Dutch Caribbean form two geographically distinct groups separated by more than 900 km of open water, it is expected that climate change will not impact these two island groups in the same way.  Aruba, Bonaire and Curaçao are located in the Southern Caribbean, an area that is predicted to become warmer and drier, with longer seasonal dry periods. Saba, St. Eustatius and St. Maarten, which are located in the Northeast Caribbean and therefore within the Caribbean hurricane belt, are predicted to experience more frequent and violent tropical hurricanes, as was evident during the disastrous 2017 Hurricane Season. All of the Dutch Caribbean’s marine and terrestrial ecosystems and the species that inhabit them will be affected, to varying degrees. Coral reefs are predicted to be especially vulnerable as higher ocean temperatures and ocean acidification will undoubtedly result in mass coral bleaching events, among other things.

Hurricane Irma, whose unforeseen rapid intensification and whose impacts as one of the strongest Atlantic hurricanes ever recorded was a direct result of climate change. Source: NOAA

The economy of the Dutch Caribbean Islands is also largely dependent on tourism and it is expected that this single economic pillar will also be drastically impacted: increase in storms and hurricanes may result in tourists’ perception of destination as unsafe; beach erosion and coral bleaching may negatively impact perceptions of destination attractiveness; there will be an increased risk of damage to coastal resort properties by violent hurricanes and other storms and of damage to tourist attractions; on Bonaire, beach erosion due to loss of shallow reefs leaves historic plantation buildings like those of Washington Slagbaai Park vulnerable.

The Dutch Caribbean Nature Alliance (DCNA) released a special edition of their free digital newsletter BioNews highlighting the challenges facing the Dutch Caribbean in the fight against climate change.  Using internationally accepted climate change predictions and (research) reports, impacts both above and below water have been defined for all six islands, stressing the need for immediate action to build resilience against the effects of climate change. Loss of nature has far reaching negative consequences for the local population since nature serves as both one of the most important sources of income and offers protection against extreme weather conditions. However, it will take a concerted effort to ensure that nature, lives and livelihoods are not lost due to inaction by decision-makers.

 

https://www.dcbd.nl/document/bionews-special-climate-change

 

Article published in BioNews 48

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

Using Satellite Imagery to Map St. Eustatius Coralita Invasion

Coralita is an invasive plant species, rapidly spreading across St. Eustatius.  A recently published report highlighted the ability to use satellite imagery to systematically map Coralita’s distribution over the island.  The approach could provide key insights into how habitat and vegetation are changing over time to aid in conservationists’ efforts to minimize the negative effects of Coralita and similar invasive species.

Coralita overgrowth (Source: Achsah Mitchell)

Coralita is a fast-growing, climbing vine with beautiful pink or white flowers. Originally from Mexico, Antigonon leptopus started out as a popular garden plant, but has expanded its territory and is now aggressively invading natural areas. Its fast-growing nature means it can outcompete most native species for terrain, quickly making it the dominant species, and reducing overall diversity. This is especially the case on St. Eustatius, where ground surveys indicate the plant already appears on 15-33% of the island.

Mapping Techniques

One of the biggest issues in controlling invasive species is accurately accounting for its presence, particularly if data needs to be collected over a wide area. This is where satellite imagery can help by providing an affordable, high spatial resolution option. A new collaborative study from the Utrecht University, University of Zurich, Wageningen University, and the Technical University of Braunschweig provided key insight by using such satellite imagery to identify Coralita. The method is successful, as areas dominated by Coralita emit a relatively distinct electromagnetic signal that can be detected by satellites. Once the distribution of Coralita has been mapped using this technique, it is possible to identify the environmental conditions associated with Coralita’s presence. This approach provides a relatively low-cost solution that is powerful, accurate and repeatable; key in identifying and monitoring its spread in the future.

“In creating this map,” said Elizabeth Haber, first author of this study, “it was my hope to produce something that could be useful for those who are caring for and protecting the incredibly special nature on Statia.”

Results

Using this method, researchers sampled 162 locations across St. Eustatius and estimated that Coralita was the dominant canopy cover (>50%) on over 3% of the island (64 ha). Perhaps more importantly, this map also showed that Coralita was not randomly distributed but generally found, for example, in areas of water accumulation, near roads or near drainage channels. Furthermore, Coralita was often found in grasslands and areas of development and is relatively rare in natural forests, highlighting how human disturbances can promote the spread of Coralita. It is important to note that data filtering and physical limitations of using satellite imagery means that Coralita growing under trees or shrubs or in smaller patches is likely underrepresented in this study.

Map of the distribution of Coralita on St. Eustatius (Haber et al., 2021)

 

Conservation Implications

Even with the physical limitations, the fact that this study is cost effective and repeatable means that consistent comparisons of Coralita’s distribution can be made over time. These comparisons are vital in understanding how populations and habitats are shifting, granting conservationists a fantastic tool in forecasting the spread of invasive species. Arguably the greatest asset of the Caribbean is its vast biodiversity. Already threats of climate change, habitat loss, invasive species and urban development are upsetting this fragile balance. St. Eustatius, although small, is home to several endemic plant species, two of which are the Statia morning glory and Statia milkweed, along with the critically endangered Lesser Antillean Iguana which could all be threatened by the habitat alterations of Coralita growth.

To read more, please find the full report on the Dutch Caribbean Biodiversity Database using the link below.

https://www.dcbd.nl/document/high-spatial-resolution-mapping-identifies-...

 

Article published in BioNews 48

 

Date
2021
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
St. Eustatius
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

Coral Monitoring Finds Annual Coral Bleaching on Bonaire

A recent report released by STINAPA notes the occurrence of coral bleaching on Bonaire between 2016 and 2020.  During this study, coral bleaching was detected every year, highlighting the need for continuous monitoring and rigorous conservation measures to build resilience moving forward.

The beautiful corals of Bonaire are loved for their stunning array of colors, but what many don’t realize is that these colors are not from the coral themselves, but small microscopic alga, referred to as zooxanthellae or symbiodinium, living within them.  This alga and coral have a symbiotic relationship, where the zooxanthellae provide nutrients to the coral in exchange for protection and habitat within the coral’s skeletal structure.  Under normal conditions, this relationship is mutually beneficially, however, if the zooxanthellae become toxic, the coral can evict their partner, leaving behind its colorless abode.

Photo credit: Kai Wulf

Climate  Change

One of the many negative effects of climate change is a slow but steady increase in average Sea Surface Temperatures (SST).  While the exact causes and mechanisms of coral bleaching are still being investigated, one theory that has strong support hypothesizes that bleaching is triggered by the production of excessive abnormal oxygen molecules.  As SSTs rise above normal (even if just for just a few weeks), the zooxanthellae are unable to effectively photosynthesize and begin to produce reactive oxygen which can damage coral tissue.  As a defensive response, the coral sometimes ejects the alga, leaving its white skeletal structure empty giving it the appearance of being “bleached”.

If enough corals eject enough zooxanthellae, this becomes known as a mass coral bleaching event. These events can last anywhere from days to months and, in extreme events, even years. Unfortunately, the coupling of worsening water conditions due to human activity (pollution, overfishing and uncontrolled land development) and stressors due to climate change have led to an increase in the frequency and duration of mass coral bleaching events.  Without the zooxanthellae producing energy, corals are forced to rely on stored energy reserves and feeding directly on zooplankton. Bleaching events can be dangerous for corals even if they do not result in direct mortality as this can leave them more susceptible to disease, decreases coral spawning success and can lead to long term changes within the community composition.

 

Photo credit: Kai Wulf

Building Resilience

Luckily, not all coral, or zooxanthellae, are the same. In fact, new research has uncovered differences between corals which host a single type of zooxanthellae versus those with a more diverse array, where some may be more tolerable to temperature shifts than others.  A new theory, known as the Adaptive Bleaching Hypotheses, even states that following bleaching events, the make up of zooxanthellae may shift within corals, allowing new, more resilient combinations of zooxanthellae to move in. This creates the opportunity for coral communities to build resilience after particularly destructive years.

Bonaire

Although global bleaching events have been happening regularly since the late 1990s, Bonaire suffered its first significant coral lost due to bleaching in 2010.  During this episode, Bonaire registered nearly 10% coral mortality among populations at 10m depth.  Since 2016, some degree of coral damage, ranging from paling to full bleaching, has occurred on Bonaire’s reefs every year.  Already, even without the official survey for 2021 being completed, divers have reported bleaching at depths of 35m and deeper.

A new report, published by STINAPA, highlights the impact coral bleaching has had within the Bonaire National Marine Park between 2016 and 2020.  Each year, after SST began to drop (usually between November and December), STINAPA surveys ten sites within the park, noting signs of bleaching. These sites included eight locations along the leeward side of the island and two off the coast of Klein Bonaire, Figure 1.  At each location, quadrants were photographed at depths of 10 and 25m, with additional photographs taken at 5m for four sites starting in 2017.

Trouble in the Deep

Over this four-year study, coral bleaching was detected within the photographed quadrants every year, affecting 26% of corals in 2016, 55% in 2017, 9% in 2018, 24% in 2019 and 61% in 2020.  It should be noted that methodology changes in 2018 may have contributed to an underrepresentation of coral bleaching.

STINAPA found that the corals most susceptible to bleaching are those found at deeper depths. Interestingly, when comparing the three depths, there were significant bleaching differences between 25 and 10m, but no significant differences between 10 and 5m.

STINAPA also found that bleaching trends from 2020 indicate that certain species of coral are at higher risk of bleaching than others.  For example, corals such as Orbicella and Agaricia (Boulder, Mountainous star and Lettuce corals) were more often bleached, yet Madracis species (Yellow pencil and Ten-rayed star corals) appear to be more resilient.

Map of the 10 coral bleaching survey sites on the leeward coast of Bonaire and Klein Bonaire. (STINAPA, 2021)

The Future

Protecting these corals will require action at all levels.  Locally, the government can help build resilience through more effective fishery management, wastewater treatment and promote responsible coastal development and sustainable tourism.  Individually we can all help by minimizing our contribution to pollution, avoiding direct contact with the reef while swimming or diving and wearing reef safe sunscreens in the water.

Together, by promoting a nature first attitude towards conservation, we can help build stronger more resilient environments to combat the threats of climate change moving forward.

 

https://www.dcbd.nl/document/coral-bleaching-bonaire-national-marine-par...

 

Article published in BioNews 44

Date
2021
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Bonaire
Author