Biodiversity

Abstract

1.  Biodiversity inventories and monitoring techniques for marine fishes often over-look small (<5  cm), bottom-associated (‘cryptobenthic’) fishes, and few stand-ardized, comparative assessments of cryptobenthic fish communities exist. We sought to develop a standardized, quantitative survey method for cryptobenthic fishes that permits their sampling across a variety of habitats and conditions.

2.  Fish-   specific autonomous reef monitoring structures (FARMS) are designed to sample cryptobenthic fishes using a suite of accessible and affordable materials. To generate a variety of microhabitats, FARMS consist of three layers of stacked PVC pipes in three different sizes, as well as a bottom and top level of loose PVC pipe fragments in a mesh basket. We deployed FARMS across a variety of habitats, including coral reefs, seagrass beds, oyster reefs, mangroves, and soft- bottom habitats across six locations (Hawai'i, Texas, Panama, Saudi Arabia, Brazil, and Curaçao).

3.  From shallow estuaries to coral reefs beyond 100 m depth, FARMS attracted distinct communities of native cryptobenthic fishes with strong site or habitat speci ficity. Comparing the FARMS to communities sampled with alternative methods (enclosed clove-oil stations on coral reefs in Panama and oyster sampling units on oyster reefs in Texas) suggests that FARMS yield a subset of cryptobenthic fishspecies that are representative of those present on local coral and oyster reefs. While FARMS yield fewer individuals per sample, they are efficient sampling de-vices relative to the sampled area.

4.  We demonstrate that FARMS represent a useful tool for standardized collections of cryptobenthic fishes. While natural substrata are bound to yield more mature communities with a larger number of individuals and wider range of specialist spe-cies, the potential to deploy and retrieve FARMS in turbid environments, beyond regular SCUBA depth, and where fish collections using anaesthetics or ichthyo-cides are forbidden suggests that they are a valuable complementary technique to survey fishes in aquatic ecosystems. Deploying FARMS in locations and habi-tats where cryptobenthic fish communities have not been studied in detail may yield many valuable specimens of unknown or poorly known species.KEYWORDSartificial habitat, biodiversity, biogeography, coral reef fishes, fish trap, fisheries-independent sampling, taxonomic inventory

Abstract
Since the severe decline of the Acropora populations in Bonaire in the 1980s, no assessment has characterized the distribution of remnant colonies. Because of their patchy distribution, a large sampling effort is necessary to adequately describe their occurrence. However, the spatial scale at which this assessment needs to be carried out makes this prohibitive with approaches such as transects using SCUBA gear and photogrammetry. This internship project aimed to optimize and apply a simple methodology trialed by relevant stakeholders on the island to obtain coarse but spatially explicit data with relatively low time-investment. Snorkelers utilizing a waterproof GPS and a slate to record coarse categorical data outlined patches of Acropora cervicornis and Acropora palmata in-situ. These were processed with an ArcGIS workflow to create shapefiles of coral patches as polygons joined to their corresponding data. The resulting polygons were used to describe the distribution of Acropora spp. along the leeward coast of Bonaire. Furthermore, these were used as ground-truthing data to test whether remote sensing imagery can be used to detect A. cervicornis remotely. 466 polygons along 14.5km of the coast were created, showing a patchy distribution of both species, more frequent occurrence of A. palmata in the northern leeward coast compared to the southern, and vice-versa for A. cervicornis. A multinomial logistic regression, maximum likelihood classification, and forest-based classification all showed a high accuracy in labelling A. cervicornis correctly in remote sensing data, but all showed frequent misclassification of other reef structures as A. cervicornis. The mapping approach presented in this internship could be applied to investigate fragmentation effects in Acropora populations and to gather in-situ ground-truthing data for other benthic habitats.

For full report or more information,  please contact erik.meesters@wur.nl or gulsah.dogruer@wur.nl

Notes from a series of sessions to jointly define a biodiversity monitoring strategy. The sessions were organized by the Dutch Caribben Nature Alliance (DCNA) and Rijksdienst Caribisch Nederland (RCN). Nature parks from Aruba (ARIKOK), Bonaire (STINAPA), Curacao (CARMABI), St.Maarten (Nature Foundation St.Maarten), Saba (Saba Conservation Foundation) and St.Eustatius (STENAPA) contributed to the sessions.

Nederlands Below

Land and freshwater mollusks were surveyed over the course of three visits in 2015, 2020 and 2021 on the Dutch and French sides of St. Maarten. Snails are important for a healthy soil and are an important food source for many species. Alarmingly, it has become clear that a number of land snail species are declining. In fact, it is suspected that a number of species will disappear completely if no action is taken soon.

Rare and/or endangered snails

Striped Helicinid (Helicina fasciata)- Photo credit: Tello Neckheim

About 49 species of mollusks (namely clams and snails) have been documented on St. Maarten. Depending on which list you use, between 15 and 16 of which are endangered, representing about a third of the island’s mollusk populations. Unfortunately, too little research has been done on these mollusks to make definitive conclusions, but it appears that four species may have already been lost, including the Apple Snail (Pomacea glauca), Marbled Physa (Aplexa marmorata), Glabrous Ramshorn (Biomphalaria glabatra) and Mottled Fingernail Clam (Eupera viridans).  And the terrestrial snails Pupiform Mountain Snail (Chondropoma pupiforme), Striped Helicinid (Helicina fasciata), Transparant Bulimulus (Bulimulus diaphanous fraterculus) and some more species are endangered on St. Maarten.

Critical Habitats

Pleurodonte guadeloupensis martinensis- Photo credit: Tello Neckheim

The main causes of the decline in populations include habitat loss due to hurricanes, pollution and construction. In fact, the island has almost no primary (or original) forest left. Secondary forest is restored forest where, in addition to indigenous species of plants and animals, there are often many introduced exotic species which can bring about a number of other issues for the island.

One particularly vulnerable habitat is forest with calcareous moist soil. On the Dutch side of the island, this habitat is mainly found at Billy Folly, where only a limited piece of original habitat is still present. Nearly the entire “mountain” has now been built up with houses. During the 2021 visit, a road was built right through the primary forest. This road will likely lead to new construction projects, which could result in the disappearance of the last remnant of forest causing the loss of any snail species bound to this area.

Another disappearing habitat is moist secondary forest on neutral soil. This habitat is mainly found on the French part around Mont Paradis. This habitat is scarce but not threatened because there are no building plans on and around Mont Paradis. On the Dutch side it is found on Sentry hill and Sint Peter hill.

Importance of snails

These snails represent an important part of the natural balance for the island.  They consume rotting leaf litter and fungi and can help recycle nutrients in the soil.  In addition, they provide food source to a number of mammals, birds, reptiles and even insects, helping convert nutrients found in the soil to a digestible food source for larger predators.  A healthy environment for St. Martin starts in the soil, so understanding and preserving these tiny island inhabitants will be critical in protecting the island’s delicate ecological balance.

Report your sightings

Have you observed snails? Report your nature sightings and photos on the website www.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

Read more

You can find the completed list of land and freshwater mollusks documented during this study on the Dutch Caribbean Biodiversity Database.

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Verdwijnen van slakken op Sint Maarten

Land- en zoetwaterweekdieren zijn onderzocht tijdens drie bezoeken in 2015, 2020 en 2021 op de Nederlandse en Franse kant van St. Maarten. Slakken zijn belangrijk voor een gezonde bodem en zijn een belangrijke voedselbron voor veel soorten. Verontrustend is de bevinding dat een aantal soorten landslakken achteruitgaat. Sterker nog, het vermoeden bestaat dat een aantal soorten volledig zal verdwijnen als er niet snel actie wordt ondernomen.

Zeldzame en/of bedreigde slakken

Striped Helicinid (Helicina fasciata)- Photo credit: Tello Neckheim

Ongeveer 49 soorten weekdieren (kokkels en slakken) zijn gedocumenteerd op St. Maarten. Afhankelijk van de lijst die gebruikt wordt, zijn er tussen de 15 en 16 bedreigd, die ongeveer een derde van de weekdierpopulaties van het eiland vertegenwoordigen. Helaas is er te weinig onderzoek gedaan naar deze weekdieren om definitieve conclusies te trekken, maar het lijkt erop dat er al vier soorten verloren zijn gegaan, waaronder de Appelslak (Pomacea glauca), Gemarmerde Physa (Aplexa marmorata), Glabrous Ramshorn (Biomfalaria glabatra) en Mottled Fingernail Clam (Eupera viridans). En de landslakken Pupiform Mountain Snail (Chondropoma pupiforme), Striped Helicinid (Helicina fasciata), Transparante Bulimulus (Bulimulus diaphanous fraterculus) en nog enkele andere soorten worden bedreigd op St. Maarten.

Kritieke Habitats

Pleurodonte guadeloupensis martinensis- Photo credit: Tello Neckheim

De belangrijkste oorzaken van de achteruitgang van de populaties zijn het verlies van leefgebieden als gevolg van orkanen, vervuiling en constructie. In feite heeft het Franse deel van het eiland bijna geen primair (of origineel) bos meer. Secundair bos is hersteld bos waar, naast inheemse soorten planten en dieren, vaak veel geïntroduceerde exotische soorten zijn die een aantal andere problemen voor het eiland veroorzaken.

Een bijzonder kwetsbare habitat is bos met kalkrijke vochtige grond. Aan de Nederlandse kant van het eiland is dit leefgebied vooral te vinden bij Billy Folly, waar nog maar een beperkt stukje oorspronkelijk leefgebied aanwezig is. Bijna de hele “berg” is nu bebouwd met huizen. Tijdens het bezoek van 2021 is er een weg aangelegd dwars door het oerbos. Deze weg zal waarschijnlijk leiden tot nieuwbouwprojecten, wat kan leiden tot het verdwijnen van het laatste restant van het bos, waardoor alle aan dit gebied gebonden slakkensoorten verloren gaan.

Een ander verdwijnend leefgebied is vochtig secundair bos op neutrale grond. Dit leefgebied komt vooral voor op het Franse deel rond Mont Paradis. Dit leefgebied is schaars maar niet bedreigd omdat er geen bouwplannen zijn op en rond Mont Paradis. Aan de Nederlandse kant is het te vinden op Sentry hill en Sint Peter hill.

Belang van slakken

De slakken vormen een belangrijk onderdeel van het natuurlijke evenwicht van het eiland. Ze consumeren rottend bladafval en schimmels en kunnen helpen voedingsstoffen in de bodem te recyclen. Bovendien vormen ze een voedselbron voor een aantal zoogdieren, vogels, reptielen en zelfs insecten, en helpen ze voedingsstoffen in de bodem om te zetten in een verteerbare voedselbron voor grotere roofdieren. Een gezonde omgeving voor St. Maarten begint in de bodem, dus het begrijpen en behouden van deze kleine eilandbewoners zal van cruciaal belang zijn bij het beschermen van het delicate ecologische evenwicht van het eiland.

Meld je natuur waarnemingen

Heb je slakken gezien? Meld dan je natuurwaarnemingen en foto’s op de website www.Observation.org of download de gratis apps (iPhone (iObs) & Android (ObsMapp)).

Soortenrapporten door lokale gemeenschappen en toeristen zijn van onschatbare waarde voor inspanningen op het gebied van natuurbehoud om het publieke bewustzijn en de algemene bescherming van soorten te vergroten. Daarnaast werken de Dutch Caribbean Nature Alliance (DCNA), Observation International en Naturalis Biodiversity Center samen aan de ontwikkeling van een app voor je telefoon voor het geautomatiseerd identificeren van soorten. Uw geüploade foto’s zijn van grote waarde om dit mogelijk te maken. Neem voor vragen contact op met research@DCNAnature.org

Meer informatie

De volledige lijst van land- en zoetwaterweekdieren die tijdens dit onderzoek zijn gedocumenteerd, vindt u in de Dutch Caribbean Biodiversity Database.

Published in BioNews 52

Abstract The Bonaire Marine Biodiversity Expedition (2019) was organized by Naturalis Biodiversity Center in Leiden (the national museum of natural history of the Netherlands), ANEMOON Foundation (a Dutch organisation of marine ecological research involving citizen science), and STINAPA Bonaire National Parks Foundation. This field survey explored the marine biota of Bonaire, an island in the southern Caribbean. Species lists were produced of several groups of organisms, which include many new records for Bonaire and also some species new for science

In exciting news for the Bonaire National Marine Park (BNMP), a sighting of Aegires sublaevis, a rare nudibranch, was documented at the Cliff dive site in 2021. Incredibly, this nudibranch has not been documented anywhere in the Caribbean, and this extraordinary discovery showcases the diversity – known and unknown – of the reefs protected in the BNMP since 1979. Bonaire continues to win scuba-diving awards worldwide for its beautiful macro-life and this discovery only further highlights why reef conservation is vitally important.  

Nudibranchs, a type of mollusk, fascinate both biologists and scuba-divers world-wide. A diverse group, members are known for their elaborate colors, ability to photosynthesize, and sometimes cannibalistic behaviors, gaining them a passionate following from both underwater photographers and scientists alike. Forums around the world unite researchers, scientists, and photographers in their quest to discover and document these tiny creatures with big personalities. It is through one such forum that researcher Dr. Leslie Wilk, co-author of Reef Creature Identification: Florida Caribbean Bahamas, tracked down author Tricia O’Malley, an amateur underwater photographer, as she had the only known photographs in the Caribbean of the rare nudibranch, Aegires sublaevis.  

Rare nudibranch Aegires sublaevis. Photo source: Tricia O’Malley

“I affectionately referred to the nudibranch as “Glow Cheese,” because I was unable to find the correct identification. Its brilliant yellow color and patchy skin made me think of a block of Swiss Cheese. I was delighted to discover it at the Cliff dive site – one of my favorite locations for macro life and night diving,” O’Malley states.  

Incidentally, through discussion with Dr. Wilk, O’Malley learned that she’d also documented another rare nudibranch at the same site – an undescribed member of the family Dorididae.  

“I take joy in night diving because the reefs truly come alive in the dark. It is astounding to me that after hundreds of dives at Bonaire, I still discover new and exciting finds on each dive. The Cliff dive site is particularly bountiful when it comes to finding nudibranchs, and I can’t tell you how excited I am to have had the opportunity to see such rare and unusual macro-life. I’m truly honored to live somewhere that declares their commitment to protecting the reefs. It just shows that there is so much more to learn about the delicate reef ecosystem and that the Netherlands should consider Bonaire’s reef to be a crown jewel to be preserved at all costs,” O’Malley continues. 

Unidentified Doridae. Photo source: Tricia O’Malley

In his research, Dr. Wilk also discovered other rare nudibranchs found on Bonaire by local naturalist, Ellen Muller. These nudibranchs are Trapania bonellenae, as well as an undescribed species of Cerberilla. These finds only serve to further highlight the extraordinary diversity of Bonaire’s reef.  

“Recent finds show that Bonaire, in particular, has several rare and undescribed species.  The rarest is Trapania bonellenae, an endemic slug named partly after the island and partly after the local resident who discovered it. Aegires sublaevis, a species rarely seen anywhere, was recently photographed at Bonaire. Undescribed species of Spurilla, Cerberilla, and Dorididae have been found in Bonaire’s shallows, but nowhere else. There is also a rare color form of Elysia flava,” Dr. Wilk states.  

Unknown Doridae. Photo source: Tricia O’Malley

“Such extraordinary aspects of Bonaire’s sea slug fauna extend to other marine taxa. For example, the preliminary results of a 2020 survey of Bonaire’s marine biodiversity, funded by Naturalis Biodiversity Center and the ANEMOON Foundation, discovered the existence of at least seven species of invertebrates that are new to science. I mention the above to highlight that on-going research is revealing Bonaire’s marine life to be more diverse and remarkable than ever expected. Accordingly, governmental authorities that create and implement Bonaire’s coastal development policies should place even more emphasis on making decisions that respect, protect, and preserve its marine environment,” Dr. Wilk states. 

Implications 

These findings provide exciting new insight into Bonaire’s coral reef ecosystems and the opportunity for new marine life discoveries. It is vitally important to protect an environment where new species are still being discovered. As development on Bonaire increases, so does the pressure on the dynamic reef ecosystem, and it will be crucial that conservation lead Bonaire’s future. 

The discovery of the Aegires sublaevis will be published in the upcoming field guide “Tropical West Atlantic Sea Slugs.” 

Report your sightings 

These nudibranch sightings have been stored in Observation.org: https://observation.org/observation/229037868/ 

Species reports by local communities and tourists are invaluable for nature conservation efforts to help increase public awareness and overall species protection.  

You can report your nature sightings and photos on the website www.Observation.org or download the free apps (iPhone (iObs) & Android (ObsMapp)). You can also send your information to research@DCNAnature.org for support with getting your data stored. 

Article published in BioNews 50.

Researchers from University of Amsterdam and CARMBABI Foundation implemented 3-dimensional reef surveying techniques to improve representation of species found within hidden cavities previously overlooked by 2D methods. 12 sites along the coast of Curacao were selected and analyzed. Improved surveying techniques will increase overall understanding of the complexities of these vital ecosystems.

Photo Source: Niklas Kornder

Coral reefs are one of the most diverse ecosystems on the planet.  Coral’s beautiful skeletal structure plays an important role in providing reef habitat, nursery and hunting ground while also protecting coastal zones.  Climate change continues to be a significant threat to these areas, making the need for accurate mapping and surveying techniques vital to researchers’ ability to detect change. Traditional mapping techniques use a 2D approach to project surface cover estimates throughout a 3D structure.  Unfortunately, this technique misses hidden habitats, such as overhangs and cavities, which can result in an under representation of biomass estimates.

Photo Source: Eric Mijts

2D versus 3D

New research from the University of Amsterdam and CARMBABI Foundation compared 2D versus 3D survey techniques. Traditionally, organism abundance was calculated as the percentage of projected reef cover.  Previously, this was done by 2D surveys, however a new strategy hopes to improve on this technique through the combination of photograph analysis, diving surveys and computer modeling. Researchers surveyed 12 coral areas on the island of Curacao, then compared 3D benthic community estimates against traditional 2D projected surface cover analysis.

The Results

During this research, scientists found that while using 2D techniques, the relative contribution of organisms which grow vertically (gorgonians and massive sponges) was up to two times and 11 times lower, respectfully, than their contribution to reef biomass.  In addition, hidden areas represented nearly half of all total reef substrate, meaning two thirds of all coralline algae and almost all encrusting sponges are not included within traditional surveying techniques.

Using a variety of different metrics, this research presents adjustments to current monitoring techniques, highlighting the importance of evaluating the ecological contributions of previously disregarded or underrepresented species.  These metric conversions can be used to complement traditional survey techniques to provide improved estimates for biovolume, biomass and element composition (stocks of organic carbon and nitrogen) within coral reef communities.

Implications

Photo source: Francesco Ungar

Understanding the true composition of coral reefs is vital for designing and implementing effective conservation strategies. Coral’s unique ability to create complex habitats is vital to maintaining high community diversity and abundance in shallow water environments.  It is estimated that nearly 75-90% of coral reef ecosystems are hidden under the surface skeleton.  This means that for every m2 that can be seen, there is up to 8m2 of additional habitat underneath. This study suggests that 2D approaches may be useful to produce relatively fast estimates of reef ‘health’ but a 3D approach is needed to understand coral reef’s true composition.

https://www.dcbd.nl/document/implications-2d-versus-3d-surveys-measure-a...

Article published in BioNews 47

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