In april 2022, the Dutch Caribbean Nature Alliance (DCNA), together with the University of Applied Sciences Van Hall Larenstein, hosted a sea urchin (Diadema Antillarum) restoration workshop on Saba. During the workshop experts and representatives from the Dutch Caribbean and Jamaica came together to join forces towards coral reef restoration. This workshop helped 21 coral experts from the Caribbean region and more than 65 online attendants, to obtain a comprehensive view of the overall situation of the Diadema sea urchin in the Caribbean, including the current die-off events and restoration techniques. Throughout the workshop important discussions took place to determine the next steps needed to mitigate the loss of Diadema sea urchins on a regional scale.
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Diadema sea-urchins play a vital role in maintaining a balanced coral reef ecosystem and their restoration is essential to assist recovery of the degraded coral reefs around Saba and St. Eustatius. A collaborative effort between University of Applied Sciences Van Hall Larenstein, WUR, STENAPA, CNSI and NIOZ studied settlement rates of sea-urchin larvae. The new findings provide insight into why the Diadema population has not been restored since the massive die-off in the mid 1980’s and are important for developing and implementing effective sea urchin restoration projects.
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That coral reefs are in decline worldwide, particularly in the Caribbean, will come as no surprise. This decades-long decline has reached a potential tipping point as the weight of the effects of climate change have come decidedly to bear on the planet’s most diverse marine ecosystem. Whether coral reefs can persist without restorative intervention is debatable, which has prompted a surge in coral reef restoration projects focusing primarily on the cultivation and transplantation of coral fragments onto degraded reefs. But that widespread approach does little to address the underlying causes of coral loss, one of which is the proliferation of macroalgae that are deleterious to corals. An emerging solution to this problem is the enhancement of herbivory on coral reefs through improved management of herbivores, artificial enhancement of herbivore settlement, or their mariculture and subsequent stocking. This review explores the nuances of the biology of well-studied Caribbean coral reef herbivores (fishes, sea urchins, and crabs) as it relates to their mariculture and investigates the promise of herbivore stocking onto coral reefs as a restoration strategy.
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Worldwide, coral reefs are rapidly declining due to increased sea water temperatures and other environmental stresses (Figure 1). To counter the extinction of major coral reef building species on the island of Bonaire, the non-profit organization Reef Renewal Foundation Bonaire is restoring degraded reef sites using corals that are grown in local nurseries. In these nurseries, corals are propagated on artificial trees using fragmentation. After 6-8 months of growth in the nursery, the corals are transplanted to degraded reef sites around the island. Over the years more than 21.000 corals have been outplanted to reef restoration sites in this way. These corals show high survivorship under natural reef conditions but remain under threat by environmental disturbances, such as increased water temperatures, diseases, and competition with macroalgae. A promising intervention to increase reef persistence and resilience is to manipulate the coral-associated microbiome. At present, the composition of the microbiome in nursery-reared and outplanted corals on Bonaire is unknown. The aim of the current project is to identify and isolate naturally occurring beneficial bacteria that may stimulate the resilience of these corals. Our key objectives are: 1) to assess the presence of functionally beneficial bacteria in corals in nursery and restoration sites on Bonaire using metagenomic screening. 2) to design culture strategies to isolate these functionally beneficial bacteria. In the future, a selection of these beneficial bacteria can be applied to the corals to increase their resilience against environmental disturbances.
De koraalriffen van de Caribisch Nederlandse eilanden St. Eustatius en Saba zijn van groot ecologisch en economisch belang. Door een opeenstapeling van bedreigingen is de hoeveelheid driedimensionale structuur op het rif afgenomen en zijn herbivore sleutelsoorten verdwenen. Het rif wordt overwoekerd met algen, die nieuwe koraalaanwas bemoeilijken. Lokale natuurbeheerorganisaties STENAPA en SCF willen artificiële riffen inzetten, om het ecosysteem door middel van “Building with Nature” te herstellen. Artificiële riffen worden wereldwijd in toenemende mate gebruikt, maar de doeltreffendheid hangt in sterke mate af van hoe er rekening is gehouden met de lokale omstandigheden en doelstellingen. Als de riffen goed functioneren kunnen sleutelsoorten herstellen en kan koraal zich weer vestigen. De natuurbeheerorganisaties willen weten hoe artificiële riffen optimaal bij kunnen dragen aan het herstel van het koraalrif ecosysteem bij St. Eustatius en op de Saba bank. Van Hall Larenstein, STENAPA, SCF, IMARES, CNSI en Golden Rock Dive Centre werken samen in het AROSSTA (Artificial Reefs on Saba and Statia) project om deze vraag te beantwoorden. Hiervoor worden verschillende soorten artificiële riffen gebouwd van lokaal natuursteen en van veelgebruikte “reef balls”. De functionaliteit van de verschillende soorten artificiële riffen wordt bepaald door gedurende 1,5 jaar de vestiging van zee-egels, vissen en koraal te onderzoeken. Na afloop van dit project zal duidelijk zijn welk type artificieel rif het meest geschikt is voor beide onderzoeklocaties. Daarnaast is bekend wat het effect is van het gebruikte materiaal en het aanbrengen van extra schuilplaatsen op de functie van artificiële riffen. Tenslotte wordt inzicht gegeven in hoeverre artificiële riffen een bijdrage leveren aan het herstel van aangrenzende gebieden. Omdat het onderzoek uitgevoerd wordt op twee locaties, met contrasterende omstandigheden, zullen de resultaten van regionaal belang zijn om bestaande en toekomstige artificiële riffen optimaal te laten functioneren.
The Dutch main water systems face pressing environmental, economic and societal challenges due to climatic changes and increased human pressure. There is a growing awareness that nature-based solutions (NBS) provide cost-effective solutions that simultaneously provide environmental, social and economic benefits and help building resilience. In spite of being carefully designed and tested, many projects tend to fail along the way or never get implemented in the first place, wasting resources and undermining trust and confidence of practitioners in NBS. Why do so many projects lose momentum even after a proof of concept is delivered? Usually, failure can be attributed to a combination of eroding political will, societal opposition and economic uncertainties. While ecological and geological processes are often well understood, there is almost no understanding around societal and economic processes related to NBS. Therefore, there is an urgent need to carefully evaluate the societal, economic, and ecological impacts and to identify design principles fostering societal support and economic viability of NBS. We address these critical knowledge gaps in this research proposal, using the largest river restoration project of the Netherlands, the Border Meuse (Grensmaas), as a Living Lab. With a transdisciplinary consortium, stakeholders have a key role a recipient and provider of information, where the broader public is involved through citizen science. Our research is scientifically innovative by using mixed methods, combining novel qualitative methods (e.g. continuous participatory narrative inquiry) and quantitative methods (e.g. economic choice experiments to elicit tradeoffs and risk preferences, agent-based modeling). The ultimate aim is to create an integral learning environment (workbench) as a decision support tool for NBS. The workbench gathers data, prepares and verifies data sets, to help stakeholders (companies, government agencies, NGOs) to quantify impacts and visualize tradeoffs of decisions regarding NBS.
