Bonaire

Abstract

Coral reefs are vital ecosystems that face significant challenges such as eutrophication, an increase in nutrient levels in aquatic systems, contributing to the decline of coral reefs. This poses a global threat (Ban, Graham, & Connolly, 2014; Adam et al., 2021), often resulting in shifts from coral-dominated to algae-dominated ecosystems (López-Londoño et al., 2021). As part of the project "Restoration of Resilience of Nature and Society in the Caribbean Netherlands," extensive research and data collection are carried out on various Caribbean islands, including Bonaire, St. Eustatius, and Saba. To gain deeper insights into land-sea interactions, water quality monitoring, including nutrient data collection, is conducted across these islands.This study investigates the variations in nutrient concentrations across the West Coast of Bonaire and Klein Bonaire. With the focus on key nutrients PO43-, NH4+, NO2−, NO3−, and the sum parameter DIN, in the marine environment, insight into the water quality state is gained. The data utilized for this research spans from November 2021 to January 2023, with the focus on the year 2022. The nutrient measurements were systematically conducted at 11 locations across the gradient of the West Coast of Bonaire and around Klein Bonaire, covering both 5-meter and 10-meter depths.

For this research, the significant influence of the temporal and spatial factors; Month, Location, and Depth were examined for each nutrient, in combination with the established thresholds.The results revealed a consistent, increasing, or decreasing trend for the different nutrients over time, all significantly influenced by both temporal and spatial factors.Although high concentrations were found for all locations and nutrients, only two locations in the North of Bonaire were found to pose a risk to the health of the coral reefs and water quality.

This study provides crucial insights into nutrient dynamics, temporal variations, and spatial changes in Bonaire's marine environment. The identified patterns and risk assessments offer valuable guidance for targeted conservation efforts aiding in the preservation of Bonaire's coral reef ecosystems amid ongoing environmental challenges.

More information; https://research.wur.nl/en/publications/temporal-and-spatial-nutrient-va...

This presentation discusses the impacts of Avrainvillea impacts on Lac Bay

Powerpoint presentation

BSc Thesis

Abstract

Mangrove forests are among the most productive ecosystems on the planet. However, the global mangrove area is decreasing annually by 0.7% - 3%. For mangrove areas in semi-arid to arid climates, salinity is one of the causes for a decrease in mangrove canopy and tree die-off. This process occurs in mangrove forests and the backwaters near the main land. Because of their location and the presence of sediments, water circulation from the seaside becomes limited.

The backwaters near the mainland become shallow, warmer and isolated compared to the rest of the seawater, which results in increasing evapotranspiration and salinity rates. Lac Bay on Bonaire is a place where the salinity of the backwaters increase and where sediments limit the water circulation. In this case study, the electrical conductivity (EC) and sediment depths (SD) are measured to assess the current situation concerning the EC and SD variety in the backwaters of the mangrove forest at Lac Bay. This is done in two different areas in the backwaters: Area 1 and Area 2. In addition, the EC is measured twice to see if the EC changes over time and a third area is used as a reference site. The results show that the measured range of the EC in Area 1 and Area 2 is between 85 mS/cm - 128 mS/cm. The measured range of the sediment depths in Area 1 and Area 2 is between 1 cm – 379 cm. Furthermore, the EC values change over time and, with some exceptions, the greatest values are found the furthest from the feeder channels, which provide water from Lac Bay towards the backwaters. The tides are also a possible factor for the water to flow over a broader mangrove area towards the backwaters. This causes exceptions on the general pattern where EC increases with distance to feeder channels. Overall, the SD gradually increases with distance to the mainland. Some local exceptions from this pattern were measured in Area 2 and could be possible due to irregularities in the underlaying bedrock. In addition, the sediment inflow in the northern part of Area 1 causes some greater values than the surround areas.

These results and conclusions provide a baseline for follow-up research. This follow-up research should focus on factors which will prevent sediment inflow and help to reduce the EC values to make it possible to restore the previous state of the mangroves.

Abstract
Seagrass is of great importance worldwide for coastal protection, carbon sequestration and as a nursery and feeding habitat for various species. However, due to climate change, eutrophication, turtle grazing and anthropogenic activities seagrass meadows are declining globally. Seagrass restoration might be a tool to restore the seagrass ecosystem and bring back the linked ecosystem services. In the case the area is ought to be suitable for restoration, different restoration methods can be used. This study will focus on the importance of sediment stabilisation for seagrass restoration of the native seagrass Thalassia testudinum and the invasive Halophila stipulacea, using biodegradable sheets that mimic the sediment stabilizing function of seagrass meadows. This study is executed in Lac Bay, Bonaire. It is expected that by using these stabilizing sheets, the balance between native and invasive seagrass can be shifted towards native seagrass occurrence. During this research we found that using sediment stabilizing root mats can improve restoration of the native seagrass T. testudinum, especially in environments with high wave action and currents. Sediment stability is provided and fragments are held in place by the use of these biodegradable sheets, which prevents fragments from washing away. However, for the long-term these biodegradable sheets are possibly negatively affecting seagrass growth, likely due to interference with rhizome growth. This should, however, be researched into further detail. The invasive seagrass species H. stipulacea does not experience advantages in terms of growth when using these root mats. Fragments of H. stipulacea are fragile and possibly suffer from different kinds of stress when implementing in between the sheets. It could be stated that by using the sediment stabilizing sheets, the balance between native and invasive species can be shifted towards native seagrass in this research. This will benefit the seagrass ecosystem and its ecosystem services. In general it can be stated that the effect of using these biodegradable sheets differs depending on the seagrass species and various environmental factors such as hydrodynamics. There is also an indication of a difference in efficiency of the use of these sheets between the short-term and long-term growth. Furthermore bioturbation is likely to influence seagrass expansion and the functionality of these biodegradable sheets, therefore further research is advised.

Abstract

Mangrove forests are essential habitats for species that are of commercial significance and provide various ecosystem services, including coastal protection. Yet, the health and size of mangrove forests are facing a global decline, raising concerns. To protect these ecosystems from further decline, understanding how to restore degraded forests is essential. Knowledge of planting methods and suitable locations can be used to improve the success of restoration activities. Mangrove Maniacs, an NGO, has been active in outplanting mangrove trees in Bonaire since 2020. However, precise documentation on outplanting details like areas, dates, numbers, and species of mangroves that are outplanted is sometimes missing. While the growth and survival of a sub-sample is monitored, there is currently no island-wide standardized long-term monitoring program. Therefore, the aim of this internship was two-fold, first, to identify the locations, species, outplant types, and densities of mangroves on Bonaire; second, to develop a long-term mangrove outplant monitoring program. Fourteen mangrove outplanting sites were identified on Bonaire, with 11 along the southwest coast (SW), 2 in Lac Bay, and 1 in Lagun. A total of 5,141 Rhizophora mangle trees and 8 Laguncularia racemosa trees were estimated to be outplanted in SW, with a survival rate of 29.6% and 100%, respectively. In Lac Bay, approximately 200 R. mangle trees were outplanted, with a survival rate of 27.5%. No data was available on initial outplanting densities at Lagun, but 48 living and 525 dead Avicennia germinans trees were counted, suggesting a survival rate of 8.4%. Additionally, a long-term monitoring program was developed to examine mangrove outplant performance and survival over time in a standardized way, while also providing insight into the role of local environmental variables on mangrove outplant performance. For this purpose, 1 to 5 permanent monitoring plots were assigned within each of the identified outplanting sites. In each of these plots, the environmental condition (i.e. water depth, salinity, dissolved oxygen concentration, pH, sediment layer thickness and organic content) were assessed and biotic measurements (i.e. tree species, tree height, stem thickness, number of living outplants, number of living leaves) were carried out. Only data from SW and R. mangle was used to analyse the influence of environmental variables on performance. Environmental conditions varied significantly among the SW sites, showing differences in dissolved oxygen, temperature, pH, sediment layer thickness, and organic content. Conductivity negatively correlated with R. mangle stem height, whereas water depth showed a positive correlation. Moreover, a positive relationship was observed between the distance to the nearest tree and the number of living leaves. Distance to the nearest tree and dissolved oxygen concentration both showed a positive relationship with the proportion of living R. mangle trees, while conductivity and sediment organic matter content showed a negative relationship with the proportion of living R. mangle trees. Based on these results, we recommend strategic planting of R. mangle along the SW coast at sites with optimal environmental conditions (i.e. low conductivity and sediment organic content, high dissolved oxygen level, minimum water level of ~10 cm). It is also advisable to avoid planting A. germinans in dry hypersaline sites in Lagun and to reduce salinity levels in the backwaters of Lac Bay to increase outplant survival. Finally, to allow monitoring of outplant survival and performance, no new mangroves should be planted within the assigned long-term monitoring plots.

BSc International Land and Water Management Wageningen University

Supervisors:
WU Supervisor: Klaas Metselaar
Host supervisor: Sabine Engel

Abstract
Mangrove forest systems and coral reefs are vital ecosystems with ecological, economic, and societal importance. However, they face threats such as excessive sediment inflow from human activities, endangering their health and resilience. This report explores sediment-related issues in the Lagun Bay catchment area on Bonaire and proposes dams as sediment control measures. Potential soil erosion was assessed and dams were designed to reduce sediment transport effectively. However, maintenance is essential for dam functionality. Though not definitive, these dam designs offer potential solutions. Sustainable land and coastal management, coupled with improved data and regular maintenance, can protect these valuable ecosystems and preserve biodiversity. Further research is needed to enhance data quality and expand the study area.

Dutch below

The local government of Bonaire, supported by the Dutch government in The Hague, recently announced the acquisition of the former plantation Fontein. With a significant investment of 3.4 million dollars, the government aims to safeguard the area’s natural and cultural significance and ensure continued public access. 

Historical Importance 

Yellow-shouldered Amazon Parrots. Photo credit: Hans Smulders

The name “Fontein” pays homage to the perpetual freshwater source that originates in a reservoir beneath the north-eastern area of Bonaire. This freshwater source has been historically crucial for the island and its inhabitants, dating back to when the indigenous Caquetio people occupied the region, evident in the petroglyphs found on the estate. 

The plantation, a part of Bonaire’s plantation complex, holds intrinsic cultural-historical value. From Spanish rule in 1499 to modern day, Fontein has been a witness to changing economic landscapes on the island.  Despite facing challenges, diligent efforts have been made to maintain, the plantation’s patterns and interactions between nature and culture remain visible, contributing to Bonaire’s identity. 

Natural Value 

Orange fruits of the Strongbark tree. Photo credit: Marjolijn Lopes Cardozo

The area of Fontein contains three freshwater reservoirs, as well as scrubland and introduced fruit trees.  Since freshwater sources on the island are sparse, this area has been identified as an Important Bird and Biodiversity Area by BirdLife International. This area supports various populations of threatened and restricted range birds, such as the yellow-shouldered Amazon parrot (lora). Funding to purchase Fontein was made possible through a Nature and Environmental Policy Plan (NEPP) related project by the Ministry of Agriculture, Nature and Food Quality and Public Entity Bonaire. The goal of this project is to recreate this freshwater paradise for all of the islands’ residents (human and otherwise) to enjoy. 

Heritage 

The government’s acquisition marks a critical step in preserving Bonaire’s heritage. Fontein’s complex history, from indigenous habitation to colonial struggles and post-slavery challenges, reflects the broader Caribbean narrative. The plantation’s value lies in tangible remains—prehistoric paintings, Dutch archaeological remnants, and landscape structures—all witnesses to centuries of habitation. 

Looking Forwards 

The government’s investment in Fontein reaffirms its commitment to valuing and preserving Bonaire’s heritage. The acquisition ensures that this historic plantation remains a living testament to the island’s past, providing a unique space for reflection, education, and community engagement. 

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 through the press. This article contains the results from several (scientific) projects but the projects themselves are not DCNA projects. 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.   

De lokale overheid van Bonaire, gesteund door de Nederlandse regering in Den Haag, heeft onlangs de overname van de voormalige plantage Fontein aangekondigd. Met een aanzienlijke investering van 3,4 miljoen dollar wil de regering de natuurlijke en culturele betekenis van het gebied veiligstellen en blijvende publieke toegankelijkheid garanderen.

Historisch belang

Geelschouder amazone papegaai. Foto: Hans Smulders

De naam “Fontein” is een eerbetoon aan de zoetwaterbron die zijn oorsprong vindt in een reservoir onder het noordoostelijke deel van Bonaire. Deze zoetwaterbron was van oudsher cruciaal voor het eiland en zijn bewoners en dateert uit de tijd dat de inheemse Caquetio bevolking de regio bezette, dit blijkt uit de rotstekeningen die op het landgoed te vinden zijn.

De plantage, onderdeel van het plantagecomplex van Bonaire, heeft een innerlijke cultuurhistorische waarde. Vanaf de Spaanse overheersing in 1499 is Fontein getuige geweest van veranderende economische landschappen op het eiland. Ondanks de uitdagingen die er zijn, zijn er ijverige inspanningen geleverd om de patronen van de plantage en de interacties tussen natuur en cultuur zichtbaar te houden, wat bijdraagt aan de identiteit van Bonaire.

Natuurlijke waarde

Oranje fruit van de Watakeli boom. Foto: Marjolijn Lopes Cardozo

Het gebied van Fontein bevat drie zoetwaterreservoirs, evenals kreupelhout en geïntroduceerde fruitbomen. Omdat zoetwaterbronnen op het eiland schaars zijn, is dit gebied door BirdLife International aangemerkt als een belangrijk vogel- en biodiversiteitsgebied. Dit gebied herbergt verschillende populaties van bedreigde vogels en vogels met een beperkt verspreidingsgebied, zoals de geelschouder amazone papegaai (Lora). De financiering voor de aankoop van Fontein is mogelijk gemaakt via een Nature and Environmental Policy Plan (NEPP) gerelateerd project van het Ministerie van Landbouw, Natuur en Voedselkwaliteit en Openbaar Lichaam Bonaire. Het doel van dit project is om dit zoetwaterparadijs opnieuw te creëren zodat alle bewoners van het eiland (menselijk en anderszins) er van kunnen genieten.

Erfgoed

De overname door de overheid markeert een cruciale stap in het behoud van het erfgoed van Bonaire. De complexe geschiedenis van Fontein, van inheemse bewoning tot koloniale strijd en uitdagingen na de slavernij, weerspiegelt de Caribische geschiedenis. De waarde van de plantage ligt in tastbare overblijfselen zoals prehistorische schilderingen, Nederlandse archeologische overblijfselen en landschapsstructuren die allemaal getuigen van eeuwenlange bewoning.

Vooruitblik

De investering van de overheid in Fontein bevestigt opnieuw haar inzet voor het waarderen en behouden van het erfgoed van Bonaire. De aankoop zorgt ervoor dat deze historische plantage een levend bewijs blijft van het verleden van het eiland en biedt een unieke ruimte voor reflectie, educatie en betrokkenheid van de gemeenschap.

DCNA

De Dutch Caribbean Nature Alliance (DCNA)ondersteunt (wetenschaps) communicatie 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) projecten, maar de projecten zelf zijn geen DCNA-projecten. 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.

Published in BioNews 69

This research was conducted as part of my bachelor internship for the Tropical Forestry specialization of the forest and nature management studies at Van Hall Larenstein, University of Applied Sciences. The internship was conducted at Mangrove Maniacs, an Bonaire based NGO that mainly works to restore the mangrove forests on the island. Field work was conducted between May and July 2022.

ABSTRACT  Marine Protected Areas (MPAs) are globally underfunded. We present a five-step framework that can help practitioners prioritize actions that may improve financial sustainability, which was applied to six MPAs in Colombia, Bonaire, and Belize. Limited funds were found to directly undermine effectiveness towards conservation goals for five sites, with these impacts particularly significant for four. Annual budgets required increases from 6 % to 141 % to meet financial needs. Two sites had significant underlying weaknesses in their financial strategies that could lead to direct impacts if not addressed, with an additional three sites having more minor, but still observable, weaknesses in this manner. Staff salaries were the largest expense for all MPAs examined and also most frequently in need of additional funds. Opportunities to potentially eliminate these funding gaps were identified for all six MPAs through reallocating existing resources (n =2), improving in-place mechanisms (n = 6), or implementing one or more alternative mechanisms (n =6). Among several findings, some MPAs had the potential to increase tourism-based income by several million dollars per year, which would well exceed local financial requirements and could have substantial financial benefits on a network-wide scale. Some MPAs, including those with lower budgets, effectively leveraged partnerships and inter-institutional coordination to expand management capacity. Among alternative mechanisms that could be implemented, opportunities to leverage private-sector investments were especially common. Other MPAs around the world could likewise improve financial sustainability through analysis, evaluation, and execution of the full suite of options described herein.