Biodiversity

University of Applied Sciences Van Hall Larenstein and Wageningen University and Research recently conducted a comparative study of artificial reefs within the Caribbean. This study provides new insights into the impacts of these structures on local marine life and neighboring ecosystems and highlight the need for comprehensive monitoring and integration into marine management plans. 

Photo credit: Rudy Van Geldere

Since the 1960s, artificial reefs have been placed around the Caribbean for tourism, to aid in improving fish stock, providing coastal protection and for scientific research. Unfortunately, there has been limited research to fully understand these reefs’ impact or compare artificial reefs to their natural neighbors. Researchers debate whether artificial reefs actually improve fish populations by encouraging increased reproduction or whether they are merely attracting fish from nearby reefs. Understanding how artificial reefs affect local fish populations and neighboring reefs will be critical in implementing meaningful conservation strategies in the future.  

 The Study 

 A new study conducted by University of Applied Sciences Van Hall Larenstein and Wageningen University and Research within the AROSSTA (Artificial Reefs on Saba and Statia, www.hvhl.nl/arossta) project aimed to evaluate the ecological effects of artificial reefs within the Caribbean. To do so, 212 different artificial reefs were analyzed based on reef type, location, deployment year, purpose, material, ecological development and fisheries management status.  

 The Results 

The results proved very insightful. It was determined that the three most common purposes for artificial reefs were to serve as new dive sites (41%), for research (22%) and to support ecosystem restoration (18%). In addition, they found metal and concrete to be the most widely used materials. They also found a number of factors which could help bolster fish populations, such as reefs which more complex geometries and those placed in areas of dense seagrass. 

This study also found that of all the artificial reefs, only 38 are located within marine protected areas which prohibit fishing. This means that over 80% of all artificial reefs are fishable. This is especially true for the Southern and Southwestern Caribbean Including Aruba, Bonaire and Curacao) where 100% of the reefs are within legal fishing zones. As artificial reefs attract part of their marine organisms from surrounding habitats, intensive exploitation by fishers can adversely affect the fish stocks in the surrounding area and thus counteract any potential ecosystem benefits. 

Photo credit: Mark Vermeij

Future Conservation

Effective marine conservation will require additional information on the impacts of artificial reefs on these local environments. The benefits of increased fish biodiversity and populations could be quickly undone by overfishing within the same area. The authors therefore conclude that the current management status of most artificial reefs in the Caribbean is a threat for its fish stocks. If implemented properly, artificial reefs could be a critical tool for future conservation efforts. Therefore, this study concluded that artificial reefs should be carefully monitored and integrated into future marine management plans.  

To find out more, you can read the full study  by clicking the DCBD link below.

https://www.dcbd.nl/document/artificial-reefs-caribbean-need-comprehensi...

Article published in BioNews 46

Manmade structures such as seawalls, breakwaters, and jetties are increasing in frequency in marine coastal environments. Overtime, these structures are unintentionally recruiting marine life such as corals, resulting in the formation of artificial reefs. A recent study in the Caribbean has revealed how the biodiversity on these artificial structures compares to natural reefs.

Coral reefs are visually very aesthetic, but above all they play a central role in the ocean. Coral reefs support over 800,000 marine species and supply numerous ecosystem goods and services. Yet sadly, corals are threatened by a combination of global climate change and local human activities such as fishing, shipping and coastal development. Natural recovery is too slow, so active restoration efforts are crucial to prevent the loss of our coral reefs.

CORALS UNDER THREAT

One method of coral reef restoration is the construction of artificial reefs. Artificial reefs come in various forms. Some are designed and deployed specifically to enhance marine life. Others, such as shipwrecks and urban structures –including jetties, seawalls and breakwaters– recruit marine life unintentionally. With increasing coastal development, the frequency of urban structures in the marine environment is increasing, yet marine communities on urban structures receive less attention in scientific research.

This old artificial reef was visibly manmade with smooth basalt blocks cemented together (Source: Naturalis Biodiversity Center)

Filling this gap, a team of researchers explored the biodiversity of urban structures at St. Eustatius, an island of the Caribbean Netherlands. Their findings are published in the scientific journal Marine Pollution Bulletin. The team consists of Claudia Hill from the University of Groningen and Myrsini Lymperaki from the University of Amsterdam, under the supervision of professor Bert Hoeksema, who is affiliated with Naturalis Biodiversity Center and the University of Groningen.

A NEW HOME FOR MARINE LIFE

The island of St. Eustatius, popularly known as ‘Statia’, is located in the eastern Caribbean and is a special municipality of the Netherlands. The island is steeped in history, having changed hands between numerous European empires and having thrived as a port of trade in the 17th and 18th century. Today St. Eustatius is much quieter, though traces of the past like remnants of ancient piers and jetties remain in the coastal water. “These ancient structures shelter a new home for marine life”, tells Claudia Hill, first author of the article. “With corals and other benthos living on the remains, altogether forming an artificial reef”, she continues.

This natural reef was partly biogenic and located on top of a rough lava underground. It supplied a variety of microhabitats in the form of crevices and overhangs.

ARTIFICIAL VERSUS NATURAL REEF

The research team compared the biodiversity on the artificial reef to that of a natural reef nearby. “We found a considerably higher biodiversity on the natural reef, with a wider range of species, a higher density of organisms, and different dominating species”, explains Hill. “We concluded by the greatly differing communities on each reef that artificial reefs can not serve as surrogates for natural reefs.” The researchers highlight, however, that the main cause for biodiversity differences lies in the deviant structural features on the reefs. The natural reef exceeds the artificial reef in microhabitats like crevices and overhangs that are beneficial to the growth of marine life.

What I personally found most surprising, is despite the artificial reef being centuries old, the cover and abundance of reef organisms is still not comparable to that on the natural reef.  But it is important to note, that whilst the artificial reef did not host an identical community to the natural reef, it still serves as a healthy and diverse reef in its own right.

-Claudia Hill

Therefore, there is still a place for artificial reefs in conservation work, as they serve to enhance the marine life of the local area. “Artificial reefs provide a promising outlook for the future of coral reefs, yet a precautionary approach must be taken to prevent any unwanted consequences, such as the invasion of non-native species.”

MORE INFORMATION

• Curious about further details of this study? Read the full publication in Marine Pollution Bulletin.
• For further details about the study, please contact Bert Hoeksema and Claudia Hill.

Text: Claudia Hill, University of Groningen, Naturalis Biodiversity Center
Photos: Naturalis Biodiversity Center

https://www.dcbd.nl/document/centuries-old-manmade-reef-caribbean-does-n...

Article published in BioNews 45

Between 2015 and 2020, researchers from the Naturalis Biodiversity Center updated the local ant species lists for the Dutch Caribbean. A large number of new species were documented, including 40 new species on Saba and 32 new species on Aruba. Understanding ant populations for these islands puts us one step closer to unlocking the complexities of the Dutch Caribbean’s unique ecosystems.

Ant (Leptogenys pubiceps) Photo credit © Zach Lieberman/California Academy of Sciences

Ants are exceptionally complex social animals, which although we encounter them almost every day, are often overlooked. These animals have highly intricate societies which parallel that of mankind. Colonies work through a division of labor and have the ability to solve complex problems through communication and teamwork. There are over 14,000 known species worldwide, but there is still much to learn about these tiny inhabitants.

Recently, researchers from Naturalis Biodiversity Center worked to update species lists for the ants of the Dutch Caribbean. Building off previous research conducted in 1930 and 1970 by H.J. MacGillavry, P. Wagenaar Hummelinck and R.H. Cobben, these lists were updated to reflect changes in the local ant populations. Through handpicking of specimens, ants were collected and sorted to determine exact species.

SSS islands

Ant (Odontomachus bauri) Photo credit ©Michele Esposito/California Academy of Sciences

Prior to the start of the most recent biological survey, only two known species of ants were documented on Saba. Through their research, Peter Boer & Marijn J. A. Boer have now documented a total of 42 ant species.  Additionally, through this same study, provisional counts of 24 and 56 species were documented for St. Maarten and St. Eustatius, respectively.

Interestingly, the surveys on Saba were conducted after Hurricane Irma, where fallen trees obstructed researcher’s ability to access some parts of the trail and heavy rainfall may have led some species of ants to shelter deeper underground, out of sight. Therefore, it is possible that there are still a number of ant species which can be found on Saba but were not accounted for in this study.

ABC islands

A new identification key was also created to cover the species found on the islands of Aruba, Bonaire and Curaçao. This key is based off the same 1930 and 1970 studies and is now supplemented with a 2020 survey of the ant species on Aruba. Interestingly, the Aruba species list was updated from 12 previously known species to 44.

Greater Importance

Understanding the local residents, both big and small, is critical for designing and implementing holistic conservation plans. Documenting the presence of specific ant species can help identify if and when any invasive species have arrived. Ants play a vital role in local ecosystems, and cataloging local species is just the first step in understanding their importance in maintaining a healthy and balanced environment.

The investigation of the ant fauna of the Dutch Caribbean is still in progress.

To learn more about the various species of ants within the Dutch Caribbean, you can find species lists at the following locations:

Species list for Saba of 42 total species.

Species list for Curaçao  of 59 total species, 6 of which were also recorded on Klein Curaçao.

Species list for Aruba of 44 total species.

As well as an identification Key for Ant Species on the ABC islands.

Report your sightings

Have you observed ants? Report your nature sightings and photos on the website DutchCaribbean.Observation.org or download the free apps (iPhone (iObs) & Android (ObsMapp)).

Species reports by local communities and tourists are invaluable for nature conservation efforts to help increase public awareness and overall species protection. Besides, DCNA, Observation International and Naturalis Biodiversity Center are working together to develop on automated species identification app for your phone. Your uploaded photos are of great value to make this possible. For questions, please contact research@DCNAnature.org

Article published in BioNews 43

Abstract

This research paper aims to understand how Aruba’s plant ecosystem is shaped and affected by the constant wind pressure present on the island. This was achieved by evaluating and comparing multiple variables related to ecosystem stability, resilience and service provision with wind exposure (leeward and windward) and wind strength through data collection and analyses and a literature review. Results showed leeward sides present higher plant population, density and species richness, while windward slopes present higher biodiversity. Furthermore, the slopes with the highest wind strength were found to have the highest variations between exposure and the lowest values. These results point to the wind having an apparent hindering effect on plant population, richness and cover while showing that biodiversity is a more robust characteristic and could thus remain unchanged under environmental stress. Defining which slopes present higher stability and resilience cannot be concluded, but windward slopes, which present plant deformation and patchy distribution, could be better adapted to stronger winds that could occur with climate change, than leeward slopes, which have vegetation that is less affected by current conditions.

Summary  

Saba is a tropical island in the Dutch Caribbean that is known for its unique ecosystems and rich biodiversity both above and below the waterline. Only 5 km from Saba lies the Saba Bank, the third largest atoll in the world and largest marine protected area of the Kingdom of the Netherlands. The rich biodiversity and abundance of marine species attracts tourists and fishermen to Saba and the Bank. Both fisheries and tourism are therefore of great socio-economic importance to Saba. However, both sectors have a direct impact on Saba’s ecosystems. For instance, in both the lobster and redfish trap fisheries, species are being overfished, with bycatch being an issue of concern. The Saba Conservation Foundation conserves and enhances the unique terrestrial and marine environment of Saba and therefore plays an important role in both sectors. 

A precautionary and adaptive management approach must be developed to halt the decline of the fisheries stocks. For this approach a mutual understanding and cooperation between stakeholders, in this case fishermen, residents and tourists, is required. A first step towards this understanding is to engage in a dialogue with them. Engaging with stakeholders is important to understand their knowledge and interests, interact more effectively with them and increase their support for given policies or programs, that may be executed by the Saba Conservation Foundation. Therefore, my internship aims to assess fishermen’s perceptions and the knowledge and attitudes of residents and tourists on and towards Saba’s fisheries.  

From a literature review and semi-structured interviews, I obtained fishermen’s perceptions on the current status of Saba’s fisheries. The perceptions of Saba’s residents and tourists on the current status of Saba’s fisheries were obtained through a questionnaire about seafood and sharks.  

Although my study was challenged by interview and questionnaire limitations, I found that fishermen have not really noticed a change in their fisheries stocks, despite the monitored decline. Furthermore, from fishermen’s perceptions it becomes clear that overfishing and bycatch are issues to be tackled, with the help of funding and/or assistance to improve the current status of Saba’s fisheries. I also found that residents and tourists know the most important commercially fished species on the Saba Bank and prefer and/or mostly eat those species as well. The most important reasons not to eat a certain type of seafood for both respondent groups relates to environmental concerns such as: endangered-, overfished- and/or protected species. Hence, residents and tourists know quite a lot about Saba’s fisheries and seem to act on that knowledge most of the time. Moreover, residents and tourists have a very high knowledge level on sharks and both a positive attitude towards them. Releasing sharks caught as bycatch is strongly preferred by both respondent groups.  

My internship shows that Saban fishermen are willing to solve the current issues of overfishing and bycatch and that residents and tourists want to see a sustainable fishery in which sharks are treated well. Therefore, it is important that fishermen, residents and tourists come together and collaborate to support sustainable fishing practices on Saba and the Saba Bank. 

The lands of the former Bolivia Plantation amount to about three-thousand three-hundred (3,300) hectares of wildlands and basically constitute the eastern quadrant of the island of Bonaire, stretching along the central east coast from Lagun  to Boka Olivia. A brief biological inventory of Bolivia was conducted  3-6 November 1997, in which semiquantitative data was collected on the terrestrial flora and fauna at 34 different sites and/or transects. With exception of most of the lower limestone terrace, Bolivia was found to be well vegetated in terms of overall vegetation cover, and to possess much in the way of of scenic landscapes.

Whereas Stoffers (1956) indicated most of the Middle (limestone) Terrace areas as constituting dry evergreen vegetation, at present most dry evergreen species are virtually absent. One consequence of this finding is that the (likely) better developed dry evergreen formations on Bonaire (e.g. Colombia, Karpata, Tolo) must now be accorded a much higher conservation priority than could heretofore be realised. 

Bolivia shows extensive signs of past agricultural use and strip-mining for coral rubble. At present feral livestock (goats and donkeys) are at clearly detrimental densities, and mining activities form an immediate threat to some very rare coastal rubble vegetation.

Based on this initial assessment, several principal conservation priorities for Bolivia can be identified. These are:

1. Nesting habitat for the Bonaire Lora, along the coastal terrace edge
2. Ecologically important food sources, especially candelabra cacti concentrated in various areas
3. The cave systems of Roshikiri and Spelonk
4. Terrace edge area along the length of the coastline
5. Coastal rubble vegetation between Spelonk and Boven Bolivia
6. Brasía terrace woodland of Beneden Bolivia
7. Washikemba woodland in the souther parts of Bolivia.

On the basis of these principal conservation values and the area's greater role as ecological corridor beween the northern and souther halves of the island, an initial scetch of recommended conservation areas is presented. The results indicate that any potential development  should be concentrated in the central section of Bolivia.

Een internationaal onderzoeksteam heeft de mariene biodiversiteit van Bonaire onderzocht. Mariene biodiversiteit zegt iets over de verscheidenheid in verschillende soorten planten en dieren onder water. Hoewel de conditie van de riffen rond Bonaire regelmatig wordt gecontroleerd en er veel foto’s beschikbaar zijn van het onderwaterleven, is de mariene biodiversiteit steeds onderbelicht gebleven. In de voorgaande decennia was dit type onderzoek vooral gericht op Curaçao, waar veel nieuwe soorten zijn ontdekt. Daarom was het aannemelijk dat onderzoek op Bonaire ook zou kunnen leiden tot het vinden van onbeschreven soorten. De voorlopige uitkomstenvan de expeditie lijken erop te wijzen dat dit inderdaad zo is. De resultaten worden nog gepubliceerd in vaktijdschriften en op gespecialiseerde websites waar ze toegankelijk zijn voor iedereen die meer wil leren over de mariene biodiversiteit van Bonaire. Speciaal voor Onderwatersport hier alvast een “sneak preview”.

The notion of an ecological corridor is to connect protected areas of high biodiversity to counteract the fragmentation of habitats, the loss of biodiversity and the negative impacts of human activities. It brings additional benefits such as strengthening ties between regions and creating a conservation area within a framework of ecological connectivity. The foundation CARIBESUR proposes the creation of a marine ecological corridor and Transboundary Marine Corridor "South Caribbean Islands" as well as the expansion of the National Parks "Paria Peninsula" and "Turuépano" and connecting them via a terrestrial ecological corridor.

NetBiome-CSA is a European funded project that aims to extend and strengthen research partnerships and cooperation for the smart and sustainable management of tropical and subtropical biodiversity in Outermost Regions (ORs) and Overseas Countries and Territories (OCTs). The NetBiome Network, with the participation of Ecologic Institute, has developed a Strategic Document that compiles a series of policy and research priorities for improving knowledge about biodiversity and the practice of biodiversity governance in the EU ORs and OCTs. The priorities emerged from participatory processes within NetBiome-CSA. The document is available for download.

The 34 European Overseas entities, including nine Outermost Regions (ORs) and 25 Overseas Countries and Territories (OCTs), are among the most intriguing and important zones in the world for biodiversity conservation. The rich biodiversity of the European Overseas Territories has nurtured generations of local populations and communities, and is a pillar for their future economic development and crucial for their long term prosperity and sustainability. However, this exceptional biodiversity in ORs and OCTs is faced with severe threats as a result of unregulated human activities and the negative impact of climate change.

In the framework of the NetBiome-CSA project, a co-design process was developed and implemented in order to mobilize panels of experts and build bridges across geographic regions. Adopting a bottom-up approach and going beyond the expertise of the scientific community and policy makers, specific attention was given to ensure that the perceptions of civil society and private economic stakeholders, which are key players in the field of biodiversity management, were taken into account.

This exercise enabled the identification of four major research topics on biodiversity management:

• Improve tools for effective participation in biodiversity management, aiming to facilitate the co-design of management and the development of scenarios and solutions using the best available scientific and local knowledge whilst managing various uncertainty factors;
• Predict effects of climate change on natural resource uses, carrying out broadscale investigations that go beyond studies directed at specific regions or specific natural resources and develop regional strategies;
• Increase the consideration of biodiversity and ecosystem services in environmental assessment and valuation methods, taking them into account when designing legislation and undertaking infrastructure design and spatial planning processes;
• Map ecological limits to extractive activities, examining linkages across habitats and species to guide decisions on limits to activities.

Addressing these Research Priorities in a collaborative approach presents significant advantages, allowing scientific experimentation at various hierarchical scales (island, archipelago, oceanic region) thereby providing a better generalization of research results to give fundamental insights into mechanisms shaping biodiversity and ecosystem processes.

By adopting a transregional and collaborative approach to these challenges, new knowledge is expected to be acquired and used in the implementation of a set of Policy Recommendations identified in the course of the NetBiome-CSA consultation process:

• Adopt a more coherent approach to spatial planning, accounting for ecological and societal considerations, incorporating cross-sectorial and interdisciplinary cooperation to balance long-term biodiversity related issues and short-term social and economic dynamics and make decisions in a context of uncertainty;
• Adapt international legislation to national/regional context, to better address the challenges faced by European Overseas regions and territories with regard to biodiversity conservation and adaptation to climate change;
• Promote more efficient and sustainable usage of natural resources, enhancing local genetic diversity while meeting society’s needs and demands and facilitating a circular economy approach;
• Put ecosystem-based management principles into practice, adopting management approaches that take into consideration the full array of interactions within an ecosystem, including human activities;
• Establish Biodiversity Indicators specific for European Overseas Regions and Territories, since existing biodiversity indicators based on European policy models and funding strategies designed for continental contexts and needs, are very often inadequate, insufficient or too general.

These Policy Recommendations and Research Priorities can effectively address the common challenges identified that, if not tackled, would endanger biodiversity in the European ORs and OCTs and jeopardise their future. 

During the HNLMS 'TYDEMAN' bathymetric expedition on the Saba Bank, April - May 1996, two observers spent 7 weeks on board and to collect data on the distribution of
seabirds, marine mammals, and human activities (fishing, shipping). The results show that the Saba Bank has a bird fauna that is relatively rich as compared with the surrounding seas, whilst the birds seem to be concentrated along the edges of the Bank. Observed cetaceans included three dolphin and one whale species. The bird and cetacean observations were made during a transitional season in which groups of animals are migrating into the area whilst others are migrating out.
Human activities included fishing (the distribution of fish pots was determined, and the activities of a few fishermen observed) and shipping. Especially the observation of large
tankers anchoring close to the edge of the Bank in areas where coral reefs occur, was identified as a threat.

The report presents the primary results of an opportunistic project which has yielded many rough but valuable data about the Saba Bank in April-May. These data are available
for future management of the Saba Bank. The preliminary elaboration of the data in this report confirm the importance of especially the edges of the the Saba Bank for birds and
suggest the Bank being a feeding area for populations that breed on the neighbouring islands. Together with the observations of different species of cetaceans, the results
confirm the idea that the Saba Bank has considerable importance or the marine biodiversity in the region of the leeward Antilles. The position of the Saba Bank, partly
within the territorial waters of the Netherlands Antilles but completely within the limits of a hypothetical Exclusive Economic Zone, offers a great promise that protection (and sustainable use) of these natural values can be legally effected.