survey

Dutch and Papiamentu below

Kralendijk, Bonaire – 10th of November – In 2018 , Naturalis Biodiversity Center conducted the first mosquito survey for the Dutch Leeward Islands (Sint Maarten, Sint Eustatius and Saba) in more than 70 years. In November, they plan to repeat these surveys, this time for the islands of Aruba, Bonaire and Curacao. The team will consist of five researchers and two students from different institutes and universities, and will be executed in close collaboration with the local vector control units of each island.

Picture of a Haemagogus chrysochlorus mosquito. This mosquito is endemic to Aruba and Curaçao, which is the only place on earth where this species can be found. Picture Carel de Haseth taken at Pos Monton, Curaçao.

In addition to being a household nuisance, mosquitoes can spread a number of human and livestock pathogens which are responsible for causing diseases such as dengue, chikungunya, malaria, Zika, Rift Valley and West Nile Fever. In the last decade, the Caribbean has seen a series of mosquito-borne disease outbreaks including the 2014 chikungunya outbreak, the 2016 Zika outbreak and several dengue outbreaks with the last one documented in 2020.

Mosquito Surveys

A new study, led by Naturalis Biodiversity Center from Leiden, the Netherlands, will assess the current mosquito biodiversity across the islands of Aruba, Bonaire and Curacao. The aim will be to visit each island for 7-10 days, setting 10-16 traps to inventory adult mosquitos. In addition, the aquatic larvae will be sampled from various potential mosquito breeding sites. These surveys will take place between November 13th and December 6th, starting in Aruba. The aim of the expedition is to gain knowledge on mosquito diversity and establish identification tools to help public health research on the islands.

The possible yield of one mosquito trap in 24 hours. Photo credit: Sam Boerlijst, 2018.

Human Health Implications

Often during an outbreak, the only way to slow down the spread of a disease is to control the specific mosquito population responsible for its dissemination. Therefore, effective management requires updated information on both local mosquito populations as well as their distribution across the islands. As environmental conditions continue to shift due to climate, paired with an increase in human population for the islands, we can expect to see changes in insect populations (such as mosquitos) in the future.

This expedition is part of the Mobocon Program, which focuses on capacity building for mosquito borne disease control in Bonaire, Sint Eustatius and Saba. This program already started in 2017 and is funded by the Dutch Ministry of Health, Welfare and Sport

Salt water rock pools can be natural breeding places for some mosquitoes. Photo: Jordy van der Beek.

EERSTE MUGGENONDERZOEK OP ARUBA, BONAIRE EN CURAÇAO IN BIJNA 75 JAAR

Kralendijk, Bonaire – 10 november – In 2018 voerde Naturalis Biodiversity Center het eerste steekmuggenonderzoek uit op de Bovenwindse Eilanden (Sint Maarten, Sint Eustatius en Saba) in meer dan 70 jaar. In november worden deze onderzoeken herhaald, ditmaal op Aruba, Bonaire en Curaçao. Het team zal bestaan ​​uit vijf onderzoekers en twee studenten van verschillende instellingen en universiteiten. Het onderzoek wordt uitgevoerd in nauwe samenwerking met de lokale eenheden voor vectorbestrijding van elk van deze eilanden.

Een mug van de soort Haemagogus chrysochlorus. Deze muggensoort is endemisch op Aruba en Curaçao, de enige plek op aarde waar hij voorkomt. Foto Carel de Haseth gemaakt nabij Pos Monton, Curaçao.

Steekmuggen zijn niet alleen vervelend, maar kunnen ook allerlei pathogenen overbrengen bij mensen en landbouwdieren, die bijvoorbeeld kunnen leiden tot ziektes als dengue, chikungunya, malaria, zika, riftdalkoorts en het westnijlkoorts. In de afgelopen tien jaar zijn er in het Caribisch gebied diverse uitbraken van door muggen overgedragen ziektes geweest, onder andere chikungunya in 2014, zika in 2016 en meerdere dengue-uitbraken, waarvan de laatste is gemeld in 2020.

Muggenonderzoek

Er komt een nieuw onderzoek onder leiding van het Leidse Naturalis Biodiversity Center om de huidige muggenbiodiversiteit op de eilanden Aruba, Bonaire en Curaçao in kaart te brengen. Het doel is om 7-10 dagen naar elk eiland te gaan, waarbij 10-16 vallen worden geplaatst om volwassen muggen te inventariseren. Daarnaast worden de larven in het water bemonsterd op verschillende mogelijke broedplaatsen van steekmuggen. Deze onderzoeken vinden plaats tussen 13 november en 6 december, te beginnen op Aruba. Het doel van de expeditie is kennis opdoen over de diversiteit van steekmuggen en het maken van hulpmiddelen voor de determinatie van steekmuggen ter  ondersteuning van het volksgezondheidsonderzoek op de eilanden.

De mogelijke opbrengst van één muggenval in 24 uur. Foto Sam Boerlijst, 2018.

Gevolgen voor de volksgezondheid

Bij een uitbraak is het beheersen van de specifieke muggenpopulatie die verantwoordelijk is voor de verspreiding van de ziekte vaak de enige manier om de verspreiding te vertragen. Daarom is er up-to-date informatie nodig over lokale muggenpopulaties en de verspreiding daarvan over de eilanden om ziektes effectief te beheersen. Aangezien de omstandigheden als gevolg van het klimaat telkens verschuiven en er steeds meer mensen wonen op de eilanden, zijn er in de toekomst veranderingen in de insectenpopulaties (zoals die van muggen) te verwachten.

Deze expeditie maakt deel uit van het Mobocon-programma, dat zich richt op capaciteitsopbouw voor de bestrijding van door muggen overgedragen ziektes op Bonaire, Sint Eustatius en Saba. Dit programma is al in 2017 gestart en wordt gefinancierd door het ministerie van Volksgezondheid, Welzijn en Sport.

Rotspoelen met brak water kunnen natuurlijke broedplaatsen zijn voor sommige steekmuggen. Foto: Jordy van der Beek.

PROMÉ INVESTIGASHON TOKANTE SANGURA NA E ISLANAN ABC DEN KASI 75 AÑA

Na 2018, Naturalis Biodiversity Center a ehekutá e promé investigashon tokante sangura na e Islariba Hulandes (Sint Maarten, Statia i Saba) den kasi 70 aña. Pa luna di novèmber nan tin planeá pa ripití e investigashon, e biaha akí riba e islanan di Aruba, Boneiru i Kòrsou. E tim lo konsistí di sinku investigadó i dos studiante desendiente di diferente instituto i universidat, i nan lo ehekutá e investigashon den kolaborashon estrecho ku e departamentonan di kontrol di vèktòr (animal ku ta plama malesa) na kada isla.

Picture of a Haemagogus chrysochlorus mosquito. This mosquito is endemic to Aruba and Curaçao, which is the only place on earth where this species can be found. Picture Carel de Haseth taken at Pos Monton, Curaçao.

Banda di e echo ku nan ta un molèster na kas, sangura por plama un kantidat di mikro organismo kousante di malesa pa hende i animal ku ta responsabel pa diferente malesa manera dengue, chikungunya, malaria, Zika, keintura di Rift Valley i di West Nile. Durante e último dékada, e region di Karibe a pasa den un seri di brote di malesa kousá pa infekshon di sangura, inkluso e brote di chikungunya na 2014, e brote di Zika na 2016 i diferente brote di dengue ku esun mas resien ta dokumentá na 2020.

Investigashon di Sangura

Un estudio nobo, bou di guia di Naturalis Biodiversity Center di Leiden, Hulanda, lo evaluá e aktual biodiversidat di sangura rònt e islanan di Aruba, Boneiru i Kòrsou. E meta lo ta pa bishitá kada isla pa un periodo di 7-10 dia, harma 10-16 trampa pa kohe sangura i traha inventario di sangura adulto. Banda di esaki, lo traha muestra di larva akuátiko for di vários potensial kriadero di sangura. E investigashonnan lo tuma lugá entre 13 di novèmber pa 6 di desèmber, kuminsando na Aruba. E meta di e ekspedishon ta pa haña konosementu di e diversidat di sangura i krea hèrmènt di identifikashon pa yuda investigashon di salubridat públiko riba e islanan.

The possible yield of one mosquito trap in 24 hours. Photo credit: Sam Boerlijst, 2018.

Implikashon pa Salubridat Humano

Hopi biaha durante un brote, e úniko manera pa baha e plamamentu di e malesa ta kontrol di e populashon di e sangura spesífiko ku ta responsabel pa sembramentu di e malesa. Pa e motibu akí, maneho efektivo ta eksigí informashon al dia tantu tokante e populashon lokal di sangura komo tambe nan distribushon riba e islanan. Komo ku kondishonnan kousá pa kambio di klima ta sigui na trese kambio den kondishonnan di medioambiente, mará na kresementu di populashon humano riba e islanan, nos por spera di mira kambio den otro populashon ekológiko (manera di sangura) den futuro.

E ekspedishon akí ta parti di e Mobocon Programa, ku ta enfoká riba kreashon di kapasidat den kontrol di malesa kousá pa sangura na Boneiru, Statia i Saba. E programa akí a start kaba na 2017 ku fondo di e Ministerio di Salubridat, Bienestar i Deporte.

Salt water rock pools can be natural breeding places for some mosquitoes. Photo: Jordy van der Beek.

Article features in BioNews 59

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

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