ecology

Abstract

Prey resources in oligotrophic tropical marine environments are often scattered and unpredictable. Tracking studies of tropical seabirds can provide critical information about ocean habitat affinities, prey choice and the utilisation of surrounding areas, which can be useful for conservation managers. Foraging studies of Red-billed Tropicbird populations in the Caribbean are scarce but increasing. We sought to expand on this by tracking chick-rearing adults using GPS devices and subsequently linking these tracking data to remotely-sensed environmental variables. We related our spatial data to opportunistic sampling of regurgitates in a globally significant nesting colony on Saba, Caribbean Netherlands. Diet samples were dominated by flying fish (Exocoetidae; numerical frequency: 70.73%), but prey items from the squid family (Loliginidae; 9.76%) and the families of flying gurnards (Dactylopteridae; 2.44%) and the ray-finned fish (Carangidae; 2.44%) were also identified, although we were unable to identify 14.63% of samples due to digestion. An additional goal of our study was to compare the foraging ecology of Tropicbirds on Saba with those nesting on St. Eustatius, located circa 25 km south-east. As expected, Tropicbirds nesting on Saba exhibited diurnal foraging patterns, travelling a maximum distance from the colony of 553.7 km, with an average trip length of 117.2 ± 144.6 km (±SD). Adults foraged in shallower, cooler waters with higher chlorophyll a concentrations and higher Exocoetidae species richness compared to travelling points. Despite the proximity of Saba and St. Eustatius, this is contrary to what was found for Tropicbirds nesting on St. Eustatius, where adults foraged in deeper waters with a low Exocoetidae species richness. However, Tropicbirds from Saba and St. Eustatius did exhibit some similarities in their foraging behaviour; specifically, foraging adults traversed multiple exclusive economic zones and marine protected areas, reinforcing our recommendation for nature managers in the Caribbean to create a transboundary network in order to effectively protect and conserve this species.

Full article available here: https://bioone.org/journals/ardea/volume-111/issue-2/arde.2022.a14/Forag...

Dutch, Papiamentu and Papiamento below

Parrotfish are more than just a pretty face. The average parrotfish spends up to 90% of its day cleaning the coral reefs. Their sharp beaks allow them to easily scrape algae off corals and rocks, essential for keeping the reefs healthy and thriving. They are especially important to reef health now given the increase in major stressors such as coral bleaching events and Stony Coral Tissue Loss Disease (SCTLD). Increased protection in the Caribbean region will be considered in the next Conference of parties for the Cartagena Convention (COPS) meeting later this year on Aruba. 

(Princess Parrotfish (Scarus taeniopterus). Photo credit: Marion Haarsma)

Coral reefs provide valuable habitat for fish and other animals. People also benefit from the many ecosystem services coral reefs provide including coastal protection, food and income from tourism and fisheries. In fact, coral reefs are one of the most important sources of income for the Dutch Caribbean islands.  

Important grazers 

(Photo credit: Marion Haarsma)

Herbivores like parrotfish play a critical role in maintaining healthy coral reefs. They help sustain the delicate balance within the reef by grazing on (macro)algae, which are the main competitors for corals for space and light. The average parrotfish spends up to 90% of its day cleaning the reef. Not only does this fish species keep the algae in check, but these herbivores also create new space for baby corals to attach and grow.  

Besides removing macroalgae and promoting coral settlement and growth, parrotfish are also natural bioeroders producing sediment by grazing on rocks, calcareous algae and corals (less than 10% of their food). Hereby they help recycle nutrients and produce “sand” for (eroded) coastal areas.  

The Global Coral Reef Monitoring Network (GCRMN) report entitled “Status and Trends of Caribbean Coral Reefs: 1970-2012″ by Jackson et al. (2014) documented quantitative trends on coral reef health over 43 years in the wider Caribbean. The report identifies that one of the major drivers of coral reef decline in the Caribbean is the overfishing of herbivores, particularly parrotfish. 

Threats 

(Parrotfish on Bonaire’s reef. Photo credit: Steph Wear)

Parrotfish thrive best in healthy coral reefs ecosystems. Therefore, these fish are subjected to the same threats as corals. This includes the negative effects of climate change, ocean acidification, pollution and diseases such as the Stony coral tissue loss disease (SCTLD). In addition, overfishing can quickly wipe out local parrotfish populations. Studies show that reefs are healthier and have a higher recovery resilience capability in locations where parrotfish are protected. This highlights the importance of parrotfish for reefs to be able recover and regrow from these threats. 

Protecting Parrotfish 

In the Dutch Caribbean- on Aruba and Bonaire- there are local rules and regulations to protect all parrotfish. On these islands it is prohibited to catch, kill, wound, or disturb them. Luckily for the other islands in the (Dutch) Caribbean, the Kingdom of Netherlands, along with the Republic of France, have formally submitted a proposal to include all parrotfish in Annex III of the Specially Protected Areas and Wildlife (SPAW) Protocol, a regional agreement for the protection and sustainable use of coastal and marine biodiversity in the Wider Caribbean Region. If approved during the next Conference of parties for the Cartagena Convention (COPS) later this year on Aruba, this measure provides a legal framework for the conservation of the parrotfish to ensure and maintain population at an optimal level in the Wider Caribbean. 

Want to learn more about local parrotfish populations? Check out the following related articles: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\ 

DCNA  

The Dutch Caribbean Nature Alliance (DCNA) supports science communication and outreach in the Dutch Caribbean region by making nature related scientific information more widely available through amongst others the Dutch Caribbean Biodiversity Database, DCNA’s news platform BioNews and the press. This article contains the results from several scientific studies but the studies themselves are not DCNA studies. No rights can be derived from the content. DCNA is not liable for the content and the in(direct) impacts resulting from publishing this article. 

Papegaaivissen zijn meer dan alleen een mooi gezicht. De gemiddelde papegaaivis besteedt tot 90% van zijn dag aan het schoonmaken van de koraalriffen. Met hun scherpe bek kunnen ze gemakkelijk algen van koralen en rotsen schrapen, essentieel om de riffen gezond te houden. Vooral nu met grote stressfactoren zoals koraalverbleking en Stoney Coral Tissue Loss Disease (SCTLD), zijn ze belangrijk om koraalriffen te helpen herstellen en opnieuw te laten groeien. Verhoogde bescherming in het Caribisch gebied zal worden overwogen tijdens de volgende Conference of parties for the Cartagena Convention (COPS) die later dit jaar op Aruba plaatsvindt.

(Prinses Papegaaivis (Scarus taeniopterus). Photo credit: Marion Haarsma)

Koraalriffen vormen een waardevol leefgebied voor vissen en andere dieren. Mensen profiteren ook van de vele ecosysteemdiensten die koraalriffen bieden, waaronder kustbescherming, voedsel en inkomsten uit toerisme en visserij. Koraalriffen zijn zelfs een van de belangrijkste bronnen van inkomsten voor de Nederlands Caribische eilanden.

Belangrijke grazers

(Foto: Marion Haarsma)

Herbivoren zoals papegaaivissen spelen een cruciale rol bij het behoud van gezonde koraalriffen. Ze helpen het delicate evenwicht binnen het rif in stand te houden door te grazen op (macro)algen, die de belangrijkste concurrenten zijn voor koralen om ruimte en licht. De gemiddelde papegaaivis besteedt tot 90% van zijn dag aan het schoonmaken van het rif. Deze vissoort houdt niet alleen de algen onder controle, maar deze herbivoren creëren ook nieuwe ruimte voor babykoralen om zich te hechten en te groeien.

Naast het verwijderen van macroalgen en het bevorderen van de vestiging en groei van koralen, zijn papegaaivissen ook natuurlijke bioeroders die sediment produceren door te grazen op rotsen, kalkalgen en koralen (minder dan 10% van hun voedsel). Hiermee helpen ze bij het recyclen van nutriënten en het produceren van “zand” voor (geërodeerde) kustgebieden.

Het rapport van het Global Coral Reef Monitoring Network (GCRMN) getiteld “Status and Trends of Caribbean Coral Reefs: 1970-2012” door Jackson et al. (2014) documenteerde kwantitatieve trends over de gezondheid van koraalriffen gedurende 43 jaar in het bredere Caribisch gebied. Het rapport identificeert dat een van de belangrijkste oorzaken van de achteruitgang van koraalriffen in het Caribisch gebied de overbevissing van herbivoren, met name papegaaivissen, is.

Gevaren

(Papegaaivissen op Bonaire. Foto: Steph Wear)

Papegaaivissen gedijen het best in gezonde ecosystemen van koraalriffen. Daarom worden deze vissen blootgesteld aan dezelfde bedreigingen als koralen. Denk hierbij aan de negatieve effecten van klimaatverandering, verzuring van de oceaan, vervuiling en ziektes zoals de Stoney Coral Tissue Loss Disease (SCTLD). Bovendien kan overbevissing lokale papegaaivispopulaties snel uitroeien. Studies tonen aan dat riffen gezonder zijn en een hoger herstelvermogen hebben op locaties waar papegaaivissen worden beschermd. Dit benadrukt het belang van papegaaivissen voor riffen om te kunnen herstellen en teruggroeien van deze bedreigingen.

Papegaaivissen beschermen

In de Nederlandse Cariben – op Aruba en Bonaire – zijn er lokale regels en voorschriften om alle papegaaivissen te beschermen. Op deze eilanden is het verboden ze te vangen, te doden, te verwonden of te storen. Gelukkig voor de andere eilanden in de (Nederlandse) Cariben heeft het Koninkrijk der Nederlanden, samen met de Republiek Frankrijk, formeel een voorstel ingediend om alle papegaaivissen op te nemen in bijlage III van het Specially Protected Areas and Wildlife (SPAW) Protocol, een regionaal overeenkomst voor de bescherming en het duurzame gebruik van de kust- en mariene biodiversiteit in de ruimere Caribische regio. Indien goedgekeurd tijdens de volgende Conference of parties for the Cartagena Convention (COPS) later dit jaar op Aruba, biedt deze maatregel een wettelijk kader voor de instandhouding van de papegaaivis om de populatie op een optimaal niveau in de wijdere Cariben te verzekeren en te behouden.

Wilt u meer weten over de lokale papegaaivispopulaties? Bekijk de volgende gerelateerde artikelen:

Fish poop: an underappreciated food source for coral reef fishes?,

Recovery of Orbicella annularis corals from parrotfish predation,

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\

DCNA

De Dutch Caribbean Nature Alliance (DCNA) ondersteunt wetenschapscommunicatie en outreach in de Nederlandse Caribische regio door natuurgerelateerde wetenschappelijke informatie breder beschikbaar te maken via onder meer de Dutch Caribbean Biodiversity Database, DCNA’s nieuwsplatform BioNews en de pers. Dit artikel bevat de resultaten van verschillende wetenschappelijke onderzoeken, maar de onderzoeken zelf zijn geen DCNA-onderzoeken. Aan de inhoud kunnen geen rechten worden ontleend. DCNA is niet aansprakelijk voor de inhoud en de indirecte gevolgen die voortvloeien uit het publiceren van dit artikel.

Gutu ta un piská ku ta bal mas ku djis unu ku nèchi kara so. E gutu averahe ta traha 90% di su bida riba tene ref di koral limpi. Ku nan boka skèrpi fásilmente nan ta raspa alga for di koral i baranka, loke ta esensial pa tene e refnan sano i salvo. Espesialmente aworakí ku tin faktornan importante manera evento di blikiamentu di koral i e malesa ‘Stony coral tissue loss disease (SCTLD)’ nan ta importante pa yuda ref di koral pa rekuperá i sigui krese. Ta bai konsiderá e aspekto di alsamentu di protekshon den region di Karibe den e siguiente Konferensia di Partido den e reunion di ‘Cartagena Convention (COPS)’ mas den kurso di e aña akí na Aruba. 

(Foto: Marion Haarsma)

Ref di Koral ta duna habitat importante na piská i otro animal. Hende tambe tin benefisio di e hopi servisionan di e ekosistema ku ref di koral ta krea, inkluso protekshon di kosta, kuminda i entrada for di turismo i peska. En realidat, ref di koral ta un di e fuentenan mas importante di entrada pa e islanan di Hulanda Karibense. 

Komedó di yerba important 

(Foto: Marion Haarsma)

Hèrbivor manera gutu tin un papel importante den mantenshon di ref di koral sano. Nan ta yuda pa mantené e balansa delikado denter di e ref dor di kome e (makro) alga, ku ta e kompetidor mas grandi pa espasio i lus. E gutu averahe ta pasa te ku 90% di su dia hasiendo ref limpi. No solamente e espesie di piská akí ta mantené e alga bou di kontrol, pero e hèrbivornan akí ta krea tambe espasio nobo pa yu di koral por ankra i krese. 

Ademas eliminando makro alga i promoviendo ankramentu i kresementu di koral, gutu ta un outor di eroshon biológiko ku ta produsí sedimento dor di raspa baranka pa kome alga i koral (ménos ku 10% di nan kuminda). Asina nan ta yuda resiklá nutriente i produsí “santu” pa áreanan (ku eroshon) na kosta. 

E rapòrt di ‘Global Coral Reef Monitoring Network (GCRMN)’ titulá “Status and Trends of Caribbean Coral Reefs / Status i Kurso di desaroyo di Ref di Koralnan Karibense: 1970-2012″ pa Jackson et al. (2014) a dokumentá tendensia di desaroyo kuantitativo di salubridat di ref di koral durante 43 aña den e region di Karibe amplio. E rapòrt ta mustra ku un di e faktornan mas grandi di dekadensia di ref di koral den Karibe ta e peska eksesivo di hèrbivor, partikularmente di gutu. 

Menasa 

(Foto: Steph Wear)

Gutu ta prosperá mas tantu den ekosistemanan di ref di koral saludabel. Pa e motibu ei e piská akí tin e mesun enemigunan ku ta krea menasa ku e enemigunnan di koral. Esakinan ta inkluí e efektonan negativo di kambio di klima, oumento di ásido (zür) den osean, polushon i malesa manera e ‘Stony coral tissue loss disease (SCTLD)’. Ademas, peska eksesivo por kaba ku populashonnan lokal di gutu. Investigashonnan ta mustra ku refnan ta mas saludabel i tin un kapasidat di resiliensia mas haltu kaminda ku gutu ta protehá. Esaki ta enfatisá e importansia di gutu pa refnan por rekuperá i krese di nobo despues di e menasanan akí. 

Protekshon di Gutu 

Na Hulanda Karibense – ta na Aruba ku Boneiru – tin lei i regulashon lokal pa protekshon di gutu. Na e islanan akí ta prohibí pa kohe, mata, heridá òf stroba nan. Afortunadamente pa e otro islanan na Karibe (Hulandes), Reino Hulandes, huntu Repúblika di Fransia, a entregá formalmente un proposishon pa inkluí tur gutu den e Anekso III di e protokòl ‘Specially Protected Areas and Wildlife (SPAW) Protocol’, un akuerdo regional pa protekshon i uso duradero di e biodiversidat marino den e Region di Karibe Amplio. Si akordá esaki durante e próksimo konferensia di partido pa e konvenshon ‘Cartagena Convention (COPS) IGM20/COP17’ mas den kurso di e aña akí na Aruba, e medida akí ta krea un kuadro legal pa konservashon di gutu pa sigurá i mantené e populashon di gutu na un nivel optimal den Karibe Amplio. 

Bo ke haña mas konosementu tokante populashonnan lokal di gutu? Chèk e siguiente artíkulonan ku laso: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\  

DCNA 

Dutch Caribbean Nature Alliance (DCNA) ta sostené komunikashon sientífiko i presentashon na públiko den region Karibe Hulandes dor di hasi informashon sientífiko relashoná ku naturalesa mas ampliamente disponibel pa medio di entre otro e Dutch Caribbean Biodiversity Database, DCNA su plataforma di notisia BioNews i prensa. E kontenido akí ta kontené e resultadonan di diferente estudio sientífiko pero e estudionan mes no ta di DCNA. No por saka ningun derecho for di e kontenido. DCNA ku e publikashon no ta legalmente responsabel pa e kontenido i e impaktonan direkto/indirekto di e artíkulo akí. 

Gutu ta mas cu djis un cara bunita. E gutu promedio ta pasa te 90% di su dia limpiando e rifnan di coral. Su piknan afila ta permitie raspa kita e alganan  facilmente di e coralnan y e barancanan, loke ta esencial pa mantene e rifnan saludabel y prospero. Specialmente awor cu e principal factornan di stress, manera e eventonan di blankia coral y malesa di perdida di tehido di piedra di coral  SCTLD (Stony coral tissue loss disease), ta importante pa yuda e rifnan di coral recupera y bolbe crece. Lo considera un mayor proteccion den e region di Caribe durante e proximo Conferencia di e partinan pa e reunion di e Convencion di Cartagena (COPS) mas despues durante e aña aki na Aruba. 

(Foto: Marion Haarsma)

E rifnan di coral ta proporciona un habitat valioso pa pisca y otro bestia. Hende tambe ta beneficia di e hopi servicionan ecosistemico cu e rifnan di coral ta brinda, incluyendo proteccion di costa, alimento y e ingresonan di turismo y pesca. De facto, e rifnan di coral ta un di e fuentenan di ingreso mas importante pa e islanan di Caribe Hulandes. 

Comedo di yerba important 

(Foto: Marion Haarsma)

Herbivoro manera gutu ta hunga un papel fundamental den mantencion saludabel di e rifnan di coral. Nan ta yuda mantene e ekilibrio delicado dentro di e rifnan door di come alga (macro), cu ta e principal competido di e coralnan pa espacio y luz. E gutu promedio ta pasa hasta 90% di su dia limpiando rif. No solamente e especienan di pisca ta mantene e alganan bou di control, sino cu tambe e herbivoronan aki ta crea espacio nobo pa e coralnan baby pega y crece. 

Ademas di elimina e macroalganan y promove asentamento y crecemento di e coralnan, e gutunan tambe ta bioerosionado natural cu ta produci sedimento door di come yerba riba e barancanan, alga calcarea y coral (menos di 10 % di su alimento). Di e manera aki nan ta yuda recicla e nutrientenan y nan ta produci “santo” pa e zonanan di costa (erosiona). 

Global Coral Reef Monitoring Network (GCRMN) nan raport titula “Status and Trends of Caribbean Coral Reefs: 1970-2012″ pa Jackson et al. (2014) a documenta tendencia cuantitativa tocante salud di e rifnan di coral durante 43 aña den Caribe Mayor. E informe ta identifica cu un di e principal impulsornan di rechaso di e rifnan di coral den Caribe ta pesca excesivo di herbivoro, particularmente di gutu. 

Menasa 

(Foto: Steph Wear)

Gutu ta prospera miho den ecosistema di rif di coral saludabel. Por lo tanto, e piscanan ey ta suheto na e mesun menasanan cu e coralnan. Esaki ta inclui e efectonan negativo di cambio climatico, e acidificacion di ocean, e contaminacion y malesa manera e malesa di perdida di tehido di coral duro. Ademas, sobrepesca por caba hopi lihe cu poblacionnan local di gutu. Estudionan ta mustra cu e rifnan ta mas saludabel y tin un mayor capacidad di resiliencia di recuperacion na luganan unda e gutunan ta proteha. Esaki ta e importancia di gutu pa cu e rifnan por recupera y bolbe crece di e menasanan aki. 

Proteccion di gutu 

Den Caribe Hulandes -na Aruba y Boneiro- ta existi norma y reglamento local pa proteha tur gutu. Na e islanan aki ta prohibi pa gara, mata, herida of molestia e gutunan. Afortunadamente pa e demas islanan di Caribe (Hulandes), Reino Hulandes, hunto cu Republica di Francia a presenta formalmente un proposicion pa inclui tur e gutunan den Anexo III di Specially Protected Areas and Wildlife (SPAW) Protocol, (Protocol di Area y Bida Silvestre specialmente Proteha), un acuerdo regional acuerdo pa proteccion y uzo sostenibel di e biodiversidad costera y marino den e Region di Gran Caribe. Si  aproba esaki durante e proximo Conferencia di e Partinan pa e Convencion di Cartagena (COPS) IGM20/COP17 mas despues durante e aña aki  na Aruba, e medida aki ta proporciona un marco legal pa conservacion di gutu pa sigura y mantene e poblacion den un nivel optimo den Caribe Mayor. 

Bo kier siña mas tocante e poblacionnan local di gutu? Consulta e siguiente articulonan relaciona cu esaki: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\  

 DCNA

Dutch Caribbean Nature Alliance (DCNA) (Aliansa pa Naturalesa di Caribe Hulandes) ta sostene comunicacion cientifico y divulgacion den region di Caribe Hulandes door di haci cu e informacion cientifico relaciona cu naturalesa ta mas disponibel a traves di, entre otro, Dutch Caribbean Biodiversity Database, (Base di Dato di Biodiversidad di Caribe Hulandes), plataforma di noticia BioNews di DCNA y prensa. E articulo aki ta contene resultado di varios estudio cientifico, pero e estudionan riba nan mes no ta estudionan di DCNA. Ningun derecho no por wordo deriva di e contenido. DCNA no ta responsabel pa e contenido y e impacto indirecto cu resulta di publicacion di e articulo aki. 

Published in BioNews 63

Abstract

Invasive alien species (IAS) are species that have been introduced to locations outside of their distributional range via human transport. In their novel exotic range, these species reach quickly reproduce and/or spread, hence the connotation “invasive”. Examples of well-known problematic IAS include tropical mosquitos bearing diseases such as Zika virus, predatory animals such as the lionfish or black rats, and plants blanketing anything they encounter. IAS are considered to be a major threat to biodiversity with extensive societal and economic consequences. However, invasive species do not become invasive overnight; invasion is the final and most detrimental stage of a much longer process. The aim of this thesis was to disentangle the natural and anthropogenic causes and consequences of species invasion by following exotic species from their origin to their impact. This thesis is structured along the different stages of species invasion and answers three overall research questions: Where do exotic species come from?; Where do exotic species end up?; What are the consequences of exotic species invasion?. The first question Where do exotic species come from? is answered in Chapter 2 that showed that exotic species and species endangered with extinction inhabit the same locations but contrast each other in terms of their traits. Both groups are overrepresented on human-impacted oceanic islands. The question: Where do exotic species end up? is answered by Chapters 3-5. In this section I conclude that within islands invaded by several exotic reptiles, these species are found almost exclusively in human-impacted environments with open or shrubby vegetation. Conversely, native species reach highest abundances in forest sites (Chapter 3). Hurricanes severely alter available habitats for reptiles (Chapter 4). Native species abundances of the lizard genus Anolis decreased with increasing levels of hurricane-induced habitat change, especially on St. Martin that was severely hit by the hurricanes Irma and Maria. Exotic species varied in their response, but we detected exotic species in previously uninvaded forests. That species from small, less populated islands also get introduced was demonstrated by the first published record of an exotic Saban anole (A. sabanus) found in the harbor of St. Eustatius (Chapter 5). This chapter serves as proof of concept that shipping is an important vector for exotic reptiles. The question What are the consequences of species invasion? is answered in Chapters 6-8, featuring the extensive invasion of the Coralita vine (A. leptopus) on St. Eustatius, impacting approximately one-third of this island. Coralita significantly alters the species composition of arthropod communities on St. Eustatius. After invasion the unique communities in urban and natural sites become homogenized to the point where they become undistinguishable (Chapter 6). The plant also has societal consequences through the reduced availability of ecosystem services (ES) (Chapter 7-8). Through a novel methodology we were able to provide estimates of ES value loss to the economy of St. Eustatius (Chapter 7-8), amounting to 42.000 dollar per year in case 3% of the island would be dominantly covered by the plant, rising to 640.000 dollar per year in case the entire range of Coralita would reach dominant coverage. We estimate that it requires a total investment of 12,7 million dollars (12% of GDP) to revert back from the worst case scenario to a Coralita-free situation. In general based on the work in this thesis I can conclude that the process of species invasion is 1) to some extent predictable at its various stages; 2) an important, independent driver of change augmented by several natural and anthropogenic factors; and 3) has major consequences for biological systems as well as human welfare and wellbeing through invasion-induced changes in ecosystem services.

https://research.vu.nl/en/publications/biodiversity-in-a-globalized-worl...

FOREWORD

Many countries are strugglingwith the task of meeting ecological and economicgoals associated with the establishment and management of protected areas. Sometimesthe attempt to meet both goals leads to conflict. For land based parks the problems are well-known: establishment of protected areas often results in depriving nearby residents of important economicbenefits from use of the flora and fauna containedin the newly protected area.

Marine parks, especiallythose found in the Caribbean,'offeropportunitiesfor both resource conservation and generationof economic benefits. The establishment of marine parks helps protect fragile coral reefs and their associated fish and plant populations. Maxine-based tourism, includingboth SCUBA divers and yachting, are also important economic activities that do not have to be in conflict with conservation and protection of the marine ecosystem.

This Dissemination Note explores these issues in the case of the Bonaire Marine Park in the Netherlands Antilles. It examinesthe impact of tourismand recreational use on the marine ecosystem, and the economicimportance of tourism and recreation to the island economy. The study is a multi-disciplinary effort as the authors include both economists (Dixon and Scura) and an ecologist (van't Hof). The paper presents an analytical approach to understandingthe dynamicsof diver impact on the Park's reefs, and describes management alternativesthat can allow increased diver use of the Park's coral reefs without exceedinga damage-inducing "stress threshold" level.

Since divers both causes stress on the marine ecosystem,and generates the revenues that pay for improved marine conservationand management,at certain levels of use the ecological and economic benefitscan be considered as a type of "joint product" of recreational diver use. Beyond the 'stress threshold" level, however, increased use leads to direct tradeoffs between marine conservationand generation of economicreturns, e.g., increasing levels of direct use result in increased income (at least in the short run), but may damage the reefs and the fish population, thereby hurting the very thing that attracted visitors in the first place.

The authors estimate that the critical stress threshold level is between 4000-6000 dives per site per year, an intensity of use that is already being exceeded in certain areas. They then suggest measures that can help increase the effectivecarrying capacity of the Park (e.g. allowing more divers into the water while minimizing negativeimpacts) and increasing the generation of income, both to help pay for park management, and to keep a larger share of economic benefits within the Bonairean economy. It shouldbe possible, therefore, to meet both ecological and economic goals.

Like other papers in this series, this DisseminationNote has not been subject to either substantialintemal review or editing. Therefore the findings,interpretations, and conclusionsexpressed are entirely those of the authors and shouldnot be attributed to the World Bank, members of its Board of Executive Directors, or the countries they represent.

A new study by researchers from the University of Texas and California Polytechnic State University documented herbivorous fishes feeding on fish fecal pellets off the coast of Bonaire.  This has never been recorded in the Caribbean before and provides a deeper understanding of nutrient recycling and insight into the diverse diets of fishes who work to keep the local coral reefs healthy.

Blue parrotfish (Scarus coeruleus). Photo credit: Marion Haarsma

Coral reefs are one of the most diverse ecosystems on the planet, but they are also limited in nutrients. So, nutrient recycling is a vital part of supporting such reef organisms and their biodiversity. Organisms can’t process all the nutrients from the food they eat, so some of these nutrients come out in their poop. A new study documented a unique upcycling technique, previously unknown within the Caribbean, herbivorous fish feeding on fish feces.

Parrotfishes and surgeonfishes are often praised as the great caretakers of coral reefs, feeding on reef algae and keeping overgrowth in check, which indirectly promotes healthy coral recruitment and growth.  Although it was previously known that Caribbean parrotfishes and surgeonfishes also fed off other food sources, such as cyanobacteria, sponges, and even corals themselves, a recent study added fish feces to this list.

The Study

This collaborative effort was co-led by Hannah Rempel, a Ph.D. student from University of Texas Marine Science Institute and Abigail Siebert, a former undergraduate student from California Polytechnic State University. They studied the foraging rates of parrotfishes and surgeonfishes on fish fecal matter. Because they found that over 99% of feces they consumed were from the Brown Chromis (Chromis multilineata), a plankton eating fish, they also observed Brown Chromis feces to see what other reef fish ate them and studied the nutritional value of these feces. The study was conducted in 2019 between June and September, across six dive sites along the western shores of Bonaire.  This research is the first of its kind within the Caribbean and paves the way for continued exploration into the topic.

Fecal pellet. Photo credit: Hannah Rempel

The Results

Throughout this study, researchers documented that almost 85% of the observed fecal pellets were ingested by fish with over 90% consumed by parrotfish and surgeonfishes alone. “Compared to algae, these fecal pellets are rich in a number of important micronutrients. Our findings suggest they may be an important nutritional supplement in the diets of these fishes” stated Rempel. Taking a closer look at the fecal matter itself, researchers found that these pellets had higher values of proteins, carbohydrates, total calories, and important micronutrients when compared to most algae.  Therefore, consuming fecal matter may play an important role in nutrient transfer within the marine environment.

Future Research

Understanding the intricate dynamics within coral reefs provides information management authorities need to safeguard these environments more effectively. These results highlight the importance of the consumption of fecal matter in upcycling micronutrients, although there is still much to be learned about the nutritional content of other food sources, such as algae mats, cyanobacteria, sponges and corals.  Fish feces may play a vital role in nutrient supply within the reef environment, emphasizing the need for further insight into this topic moving forward.

For more information you can find the full report on the DCBD by using the link below.

More info in the Dutch Caribbean Biodiversity Database

Published in BioNews 53

Abstract.– Intraspecific diversity is among the most important biological variables, although still poorly understood for most species. Iguana iguana is a Neotropical lizard known from Central and South America, including from numerous Caribbean islands. Despite the presence of native melanistic I. iguana populations in the Lesser Antilles, these have received surprisingly little research attention. Here we assessed population size, distribution, degree of melanism, and additional morphological and natural history characteristics for the melanistic iguanas of Saba, Caribbean Netherlands based on a one-month fieldwork visit. Using Distance sampling from a 38- transect dataset we estimate the population size at 8233 ±2205 iguanas. Iguanas mainly occurred on the southern and eastern sides of the island, between 180-390 m (max altitude 530 m), with highest densities both in residential and certain natural areas. Historically, iguanas were relatively more common at higher altitudes, probably due to more extensive forest clearing for agricultural reasons. No relationship was found between the degree of melanism and elevation, and few animals were completely melanistic. Furthermore, we found that body-ratio data collection through photographs is biased and requires physical measuring instead. Although the population size appears larger than previously surmised, the limited nesting sites and extremely low presence of juvenile and hatchling iguanas (2.4%), is similarly worrying as the situation for I. delicatissima on neighboring St. Eustatius. The island’s feral cat and large goat population are suspected to impact nest site quality, nest success, and hatchling survival. These aspects require urgent future research to guide necessary conservation management.

This one-year pilot project aims to provide an insight in the ecology of Antigonon leptopus (Corallita) an invasive vine, which is overgrowing the native vegetation (Photo 1). This pilot project is just a first step in controlling the Antigonon leptopus. This research was done on a small scale and under controlled circumstances. Our ideas are just for small scale use in town but also to eradicate ‘hotspots’ to prevent further spreading especially near the National Parks. The government with STENAPA as a consultant should take further actions to continue this project and put it as a high priority. The first step was made and we hope this will contribute in containing the species and monitoring the species closely. More research on the life circle and possible natural enemies and its sensitivity for herbicides should be done in order to start a larger scale eradication campaign. The project does not stand on its own, the vine contributes in the prevention of soil erosion on the island. A full size project including replanting/reforestation with native species and renewed agricultural activities should be set up for the long term.

Objectives

• The primary research aim is to reduce and control the growth of Corallita on St. Eustatius and to prevent the species from invading the national parks. In order to achieve this, it is necessary.
• To gather information about the ecology of the species, such as its life cycle, dispersal, germination capacity, use of the species by animals etc. • To gather information about how the species will react on different potential control methods.
• Inform the local community about control methods if usable results are obtained.

Discussion and conclusion

Three weeks after the first treatment at Gallow Bay no regrowth was observed, this means the herbicide does work with smaller concentration (12.5% and 25%) on short term. After six weeks the first regrowth was observed. The tubers are still intact after the first treatment. It is not known how many times the treatment with these concentrations is needed.

In both plots of Sandy Road the plants have regrowth after 7½ weeks. Our observation on 13th January 2007 showed that a lot of Corallita was growing from the border into the plots covering the soil. The treatment did work but probably needed a second treatment if there is regrowth of 30-40cm. Further monitoring of large plots (during one year) is needed to make sure smaller concentrations will kill the plants. Tubers should de dug up and checked on viability. New plots should be selected.

The present paper deals with the Anasca and Ascophora Imperfecta of the inland bays of Curaçao and Bonaire. Collections were made by P. Wagenaar Hummelinck (1930, 1936/ 37, 1948/49, 1955, 1963/64, 1968, 1970, and 1973) and by the author (1982), and stored in the collections of the Rijksmuseum van Natuurlijke Historie, Leiden. A total of 25 species – almost all occurring in inland bays – are described here and fully illustrated. Six new species are established: Crassimarginatella harmeri, Scrupocellaria curacaoensis, Scrupocellaria carmabi, Scrupocellaria piscaderaensis, Scrupocellaria hildae and Bugula hummelincki. Attention is given to the ecology of the species. The bays have been compared as to species composition in relation to substrate and conditions during collecting.

Results of a three year study (1975-1978) of Flamingos on Bonaire and in Venezuela, including population size, food availability, migration and nesting patterns.

On Bonaire the numbers of flamingos now do not differ significantly from those found before the Salt Works started. Nevertheless the food situation for the flamingos has deteriorated. The area available to them has been diminished and it seems they prefer the food in Venezuela. They do feed readily in the Salt pans though and there is abundant food available to them once they accept the snails as food item. There are signs however that the predation on Gemma purpurea is too heavy. It is unlikely that the gypsum crust in the higher pans will be removed. The management of the AISCO is however convinced that a biological management is absolutely necessary for the salt production too. It is to be expected that the dumping of fertilizers will enhance the organic production in the salt pans and hence the food supply for the flamingos. As explained there are certain dangers to this fertilizer program too. In changing the flow system the AISCO should take into account the effect of this on the flamingo-population. Also plans for harvesting brine shrimps must be weighed against the needs of the flamingos. Therefore it would be useful if e.g. 4 times a year there would be a control on the biological processes in the salt works. Biologists from the Caribbean Marine Biological Institute (Carmabi) on Curaçao could help out with this, possibly under auspices from the Stinapa, the foundation for nature conservancy in the Netherlands Antilles. It is clear that too much disturbance takes place, especially in the Sanctuary. A stricter guard should be kept to keep possible intruders out. The best solution would be if the government of Bonaire would appoint a special guard for the flamingos, at least for the breeding season. The airport officials should be more aware of their task to keep planes from entering the forbidden area and if a plane would tresspass stern measures should be taken against the pilot. It is highly recommendable to build some kind of observation post from which tourists can have a look at the breeding colony. A telescope (the type in which you have to throw a coin to look) seems to be in the possession of the Bonaire government already. An ideal place to put it would be the house next to the red slavehuts . It would prevent a lot of disappointment for bird-watching tourists, and justify the name of Flamingo island for Bonaire. An operator at the place could serve at the same time as guard for the flamingo-colony.

At the entrance to Lake Goto an oil-terminal has been built, far with little disturbance for the flamingos. Care should be so taken however that by a further expansion of this terminal lake Goto and its shores remain completely untouched. Especially the seapage from sea through the coral debris wall at the entrance of the lake should not be disturbed as this together with the high evaporation maintains the highly salinity environment.

The plantation Slagbaai has recently come into the possession of Stinapa. Plans are ready to open this area to the public and some facilities for visitors will be made. As the flamingos reside in the landlocked bay, and especially near some buildings which will be restored and put into use, care should be taken that the flamingos will not be chased by too eager bird watchers or photographers.

Detecting patterns of spatial genetic structure (SGS) can help identify intrinsic and extrinsic barriers to gene flow within metapopulations. For marine organisms such as coral reef fishes, identifying these barriers is critical to predicting evolutionary dynam- ics and demarcating evolutionarily significant units for conservation. In this study, we adopted an alternative hypothesis-testing framework to identify the patterns and pre- dictors of SGS in the Caribbean reef fish Elacatinus lori. First, genetic structure was estimated using nuclear microsatellites and mitochondrial cytochrome b sequences. Next, clustering and network analyses were applied to visualize patterns of SGS. Finally, logistic regressions and linear mixed models were used to identify the predic- tors of SGS. Both sets of markers revealed low global structure: mitochondrial ΦST = 0.12, microsatellite FST = 0.0056. However, there was high variability among pairwise estimates, ranging from no differentiation between sites on contiguous reef (ΦST = 0) to strong differentiation between sites separated by ocean expanses ≥ 20 km (maximum ΦST = 0.65). Genetic clustering and statistical analyses provided additional support for the hypothesis that seascape discontinuity, represented by oceanic breaks between patches of reef habitat, is a key predictor of SGS in E. lori. Notably, the esti- mated patterns and predictors of SGS were consistent between both sets of markers. Combined with previous studies of dispersal in E. lori, these results suggest that the interaction between seascape continuity and the dispersal kernel plays an important role in determining genetic connectivity within metapopulations.