With the transition of the islands of Bonaire, St. Eustatius and Saba (BES) from the former Netherlands Antilles to special municipalities of the Netherlands on the 10th of October 2010, the Netherlands gained a significant amount of biodiversity. The Ministry of Economic Affairs, Agriculture and Innovation (EL&I) has gained an important new area of responsibility in terms of nature policy and management. Ecological monitoring can assist in directing management action and conservation of natural areas. It is essential that biodiversity on the BES-islands is monitored, particularly as it is threatened by a large array of natural and human factors. Aside from the national responsibilities that the Kingdom of the Netherlands holds for monitoring nature and biodiversity in these special municipalities, the Netherlands also has international obligations stemming from their participation and membership in global and regional environmental treaties.
This report aims to establish a foundation and define several priority action points for setting up a structural biodiversity monitoring system on the BES-islands, by investigating and contrasting the development, character and organization of biodiversity monitoring in the Netherlands with that of the BES-islands. This research was conducted using purely qualitative research methods; a literature review was conducted, various interviews were conducted in the Netherlands, surveys were distributed amongst actors involved in monitoring on the BES-islands, web-based research was used, and personal communication with a former representative of the Netherlands Antilles Central Government Department of Nature and the Environment as well as advice from two experts from Wageningen Institute for Marine Resources and Ecosystem Studies complemented the research.
The researched shows that if the Kingdom of the Netherlands wants to be able to provide complete national and international reporting on biodiversity and nature policy, additional monitoring is required on the BES-islands. Nature monitoring in the Netherlands has existed for more than 10 years for both the terrestrial and marine environment, is very well organised and steered by government demand. Though there are already biodiversity monitoring activities taking place on the islands and there have been several attempts to coordinate monitoring efforts on the BES-islands, monitoring activities are not organised and the necessary foundation for a structural monitoring system is still lacking. Thus, we are faced with a situation where there is quite a lot of data in existence but no infrastructure in place to organise structural terrestrial and marine biodiversity monitoring. Based on the conclusions it is recommendable to set up a monitoring network with all current parties involved in biodiversity monitoring in order to establish agreements on monitoring priorities and information sharing. In addition to this, a data storage and management system must be set up with someone responsible for data maintenance and reporting. A last vital action point is to define monitoring priorities based on the information available in this report and optimize monitoring methods.
The marine exotic species of the Dutch Caribbean are less well-known than its terrestrial exotics. So far, only 27 known or suspected marine exotic species, some of which are also invasive are documented for one or more islands of the Dutch Caribbean. Four of these were documented only once or were only present for a certain period of time and are no longer present. Six of the species are marine epidemic diseases. As very little is known about these diseases, they might actually be native, but based on the literature and their ecological signature we regard them as special cases of invasive species.
In addition to these documented species, 76 other exotic species that have already been observed elsewhere in the Caribbean may already be present or can be expected to arrive in the Dutch Caribbean in the near future. The marine communities of the Dutch Caribbean have suffered major changes based on a handful of marine exotic and/or invasive species, particularly in the special case of (opportunistic) pathogens. In certain cases experience shows that after decades, the affected systems/species may show slow signs of recovery from initial impacts (e.g. the green turtle fibropapillomas), while in other cases the impact may be long-lasting and recovery doubtful (e.g. sea fan mortality).
Compared to terrestrial exotic species, eradication and control have been proven difficult or impossible for marine exotics. Therefore, management practices aimed at controlling unwanted species introductions should focus on preventing the arrival of such species by ships-- that transport exotics in their ballast water or as fouling communities on their hulls-- and (accidental) introductions from aquaculture or the aquarium trade. Busy harbors can be expected to be the areas where most marine exotics likely establish first.
Because of dispersal of marine exotics is facilitated by ocean currents, local approaches to prevent their arrival or reduce their numbers will be less effective compared to similar efforts for terrestrial species. In the case of marine exotics and invasives, it is paramount that prevention, control and management efforts should be regionally integrated. We conclude this report by listing a number recommendations on how to develop effective management approaches with which to address the impacts and risks associated with marine exotic species.
This research is part of the Wageningen University BO research program (BO-11-011.05-004) and has been financed by the Ministry of Economic Affairs, Agriculture and Innovation (EL&I) under project number 4308202004.
The aim of this study was to draft a generic ecological assessment framework for coastal systems in Caribbean Netherlands (CN) that offers guidance in the process of license-applications of planned activities that could impact coastal systems, as well as a general guidance towards environmental and ecological monitoring related to proposed projects and existing activities. The study was limited to the review of (inter)national ecological assessment frameworks and monitoring initiatives; peer-reviewed academic literature was not consulted. Though this draft framework provides guidance, it limits itself to standard practice and general regulations. Further fine-tuning of the framework is required to be applicable to the specific situation in CN. Furthermore, it is the responsibility of the individual initiators to customize an adequate and comprehensive ecological impact assessment and monitoring-plan adjusted to the spatial and temporal scale relevant of the type of activities and possible impact resulting from the project.
Fundamental to the draft framework is a network approach in which the impact chain between the activity and ecosystem components is specified by a suit of pressures. The broad strategy of the ecological assessment framework consists of three major phases:
- Establishing the context in which the project will take place.
- Scoping of the project activities, their pressures and the environmental descriptors relevant to the projected area.
- Assessment and evaluation of the pressures on the environmental descriptors.
For each phase practical guidance is provided in the form of questions. While answering these questions an overview is established of all relevant activities, pressures, and environmental descriptors. Each phase is further elaborated upon in the report. An adaptive and interactive management approach is required for the processes of the three phases. Informative environmental descriptors groups were identified based on international monitoring initiatives (Benthic diversity, Coral health, Species requiring special attention, Fish diversity, Chemical water quality, Physical structure) and for each descriptor indicators are proposed. Further study is required into which indicators are most appropriate for CN.
Threshold levels are not commonly available for each of the environmental descriptors. Significance testing in the absence of threshold levels is discussed in de report. A practical guidance is proposed to evaluate and categorize the significance of an impact by listing questions related to the nature, magnitude and intensity of the (expected) impacts. Reference is made to relevant (inter) national treaties or ordinances in which qualitative goals are reported.
This report provides practical guidance and considerations on how to establish appropriate reference situations in a changing environment. The reference situations must be chosen using best available information about the physical and biological characteristics of the environment to ensure that they represent suitable reference conditions. Important factors to consider are summed up in this report. A well set-up monitoring design should include multiple reference sites (spread across space and time) to allow the authorities and the initiator to tease apart natural variability and general trends in decline (e.g. due to climate change) from changes caused by the initiated project.
The proposed framework has not yet been tested with pilot situations or cross-referenced with the legal framework in CN, nor has it been evaluated with stakeholders. It is highly recommended to evaluate this framework by applying it to pilot or actual cases, and to adapt were necessary.
To protect deep-sea biodiversity, the United Nations have adopted a number of resolutions that should protect vulnerable marine ecosystems (VMEs), such as cold water corals and sponges, by the regulation of deep-sea fisheries on the high seas. In a parallel process, the Convention on Biological Diversity (CBD) calls upon states to identify Ecological and Biological Significant Areas (EBSAs) that serve as focal areas, without any special legal status, and establish a network of marine protected areas by 2012. In addition, at the tenth meeting of the Conference to the Parties of the CBD in Nagoya, in 2010, it was agreed that by 2020, 10% of coastal and marine areas should be protected.
The Netherlands is involved in both processes since our country has ratified the CBD and therefore is bound to contribute to the protection of biodiversity, both in its national waters and in the high seas. In this report we provide a worldwide overview on the protection of VMEs and of the status of the EBSA selection processes as per March 2012. Next, we zoom in on three areas that are of interest to the Dutch government (Caribbean, West Africa, Antarctica) and we summarize the spatial protection measures, list the closed VME areas and EBSA selection processes and we provide information on the regional seas conventions and their mandates.
On the island Bonaire, eutrophication is a point of serious concern, affecting the coral reefs in the marine park. Eutrophication can cause altered balance of the reef ecosystem because algae can outcompete corals, leading to a disturbed composition and deterioration of the biodiversity of the reef. The reef of Bonaire faces nutrient input by various sources, of which enriched groundwater outflow from land to the reef is considered to be a substantial one. Groundwater is enriched with nutrients e.g. due to leaking septic tanks.
In order to reduce the input of nutrients on the reef via sewage water, a water treatment plant is being built on Bonaire. The treatment of sewage water will be extended in 2012 with a sewage system covering the so called sensitive zone, the urbanised area from Hato to Punt Vierkant. Based on the dimensions of the treatment plant and estimated connections to the plant, it can be assumed that a total of 17520- 35040 kg of Nitrogen a year is removed from the sensitive zone, and will not leach out to the sea at the western coast of Bonaire. No estimates are known of the contribution of other sources to the total nitrogen load.
At the moment limited information is available about concentrations of nutrients in the marine environment. Therefore, Rijkswaterstaat Waterdienst asked IMARES to conduct a monitoring study. The goal of this coastal monitoring study was to collect baseline water quality data to be able to study the effectiveness of the water treatment plant in coming years.
The study consisted of two phases and resulted in two reports:
1. recommendations for baseline monitoring in 2011,
2. monitoring, data evaluation, and recommendations
In this second report, monitoring data are presented and discussed, and recommendations for future monitoring are provided. Options for dissemination of data and data management are presented.
In November 2011, field monitoring was performed at ten locations at the west coast, at two depths -6m and -20 m. Three of these locations lay with the “sensitive zone” and are suspect of enriched groundwater, being a diffuse source of nutrients. Other locations are regarded as relative reference locations, laying further offshore, north or south from the sensitive zone. The prevailing current is from south to north. The reference locations might be influenced indirectly by the (diffuse) source under study, or can be under pressure by other nutrient sources as e.g. the salt company in the south.
Monitoring data are compared to environmental threshold values for tropical ecosystems. In Figure I, a summary of this evaluation is presented. Data show that during this monitoring study, eutrophic conditions, based on DIN concentration, are observed at four out of ten locations: Habitat, Angel City, Cargill and Red Slave. No clear difference in eutrophic state between the sensitive zone and other locations is observed. Cargill, Red Slave and Angel city are influenced by percolation of enriched groundwater from the salt pans.
Nutrient concentrations in the “sensitive zone” do not clearly differ from reference observations at e.g. Playa Funchi, Karpata and Klein Bonaire, but bacteria counts do. Bacteria numbers at Habitat and Playa Lechi exceed EU, EPA and Caribbean Blue flag standards. Stable nitrogen isotope ratios in macro algae show large variability and low average values near background levels, and are not specifically indicative for nitrogen related to sewage sources. Along developed coastlines with e.g. addition of inorganic fertilizer with low δ15N values will complicate the study for a sewage signal. Analysing δ15N and organic N in groundwater should be considered in next monitoring in order to explain the low ratio found in this study. Statistical similarity analysis between locations shows no similarity and relation to position of the location (within sensitive zone or reference). Location “Habitat” showed a clear dissimilarity compared to the other nine locations, and it is assumed brine effluent from WEB could be a steering factor in this observation.
The study of November 2011 leads to the following conclusions:
- Benthic surveys were not included in this study, and add largely to a whole ecosystem assessment on eutrophication. In upcoming research this should be included.
- Based on nutrient levels, in the south and in one location in the sensitive zone a eutrophic status was observed. The other locations did not have nutrient levels harming the development of a healthy coral reef, based on nutrient concentrations alone. Nutrients levels are however in a constant flux, and data should be considered in an ecosystem context.
- Enriched groundwater with nutrients from sewage is not the only source of nutrients. Other sources as nutrients from the salt pans in the south and from brine near Habitat probably add to the eutrophic status at these locations. Furthermore percolation and surface run off from Salinas and stormwater via roois are probably a source of nutrients as the isotope values at the other locations are low too.
- Monitoring in the coastal zone alone, will not provide adequate indication of the effectiveness of the treatment plant. Monitoring in the coastal zone is effective to detect areas at risk, and to detect long term changes in overall water quality (= so called “surveillance monitoring”).
- Monitoring in the coastal zone should be supported by additional so called “investigative monitoring” at the sources to quantify the relative contribution of each of these sources in order to be able to discuss additional measures.
Above mentioned preliminary conclusions need to be considered using additional monitoring. Based on a one time monitoring activity no definite conclusions are possible related to the treatment plant.
“Surveillance” monitoring in the coastal zone will identify areas at risk, determine long-term changes in water quality, and can be used to evaluate environmental risk assessment.
Indicators to include are: nutrients (NH4, NO2, NO3, DIN, PO4, Total P, organic (kjeldahl) nitrogen) bacteria, benthic composition. The added value of N15 is questioned because of the average low response and high variability. A reference locations further offshore has to be added.
A clear advise on minimum frequency cannot yet be given as seasonal and diurnal variance is evident, but the extent not yet identified. Seasonal and diurnal dynamics (and thus variance) in nutrient availability is common at reef systems. Factors steering this seasonal variance are e.g wet and dry season, dynamics in regional upwellings, atmospheric pressure, biannual tidal regime, and irregular discharge in both quality and quantity. Suggestions for getting grip on this variance is provided in the report. A minimum frequency of monitoring in dry (May/June) and wet season (October/November) is suggested by parties involved. This frequency is a starting point, but could however be too low to detect significant trends. Future data have to be evaluated and monitoring has to be adapted according to the new results. Integration of these data with benthic survey data is considered to be a priority.
“Investigative monitoring” should be directed to measurements and evaluation of the quantity and quality of the sources and can be used to establish causal relations. In relation to the effectiveness of the treatment plant, it is advised to direct “investigative” monitoring to:
- quantity and quality of the influent and effluent of the Water Treatment Plant
- quantity and quality of other sources of nutrients via e.g. groundwater monitoring
- Industrial sources (salt company, WEB brine effluent)
- Salinas and roois
Indicators to include are: BOD, COD, bacteria, nutrients (NH4, NO2, NO3, DIN, kjeldahl N, PO4, total P), and 15N. Scenarios for field work are presented and cost estimates provided in the report.
Synchronization and support of STINAPA research
Options to integrate and support ongoing research by STINAPA are discussed in the report. The processing of obtained data by the benthic surveys is time consuming and therefore not yet available. Second subject is the dissemination of results from project “light and motion” by the university of California. These data could very well fit into an exploration of remote sensing as a cost effective monitoring technique for water quality. Both subjects could contribute largely to the assessment of water quality in the coastal zone of Bonaire and aid management decisions. Data analysis via e.g. student projects should be considered as an option.
Data management and dissemination of results:
Regarding data management and dissemination of results it is advised to further explore and to contribute to the development of the WUR portal on BES data and use the ISO standard by SeaDataNet to describe metadata. The WUR portal provides the opportunity of storing all BES data in a format of choice. Excel tables and figures, including the reports can be uploaded, and could for the time being be suitable enough to disseminate the data. The portal is under development and options for dissemination will be gradually extended and improved. If chosen to describe the monitoring and data with a metadata format prescribed by international standards, in time, the (meta) data could be synchronised with any other system.
The location of the portal is http://scomp0703.wur.nl/bioplanbes/.
On the island Bonaire, eutrophication is a point of serious concern, affecting the coral reefs in the marine park. Eutrophication can cause altered balance of the reef ecosystem because algae shall outcompete corals, eventually leading to a disturbed composition of the reef.
The reef of Bonaire faces nutrient input by various sources, of which enriched groundwater outflow from land to the reef is considered to be a substantial source. Groundwater is enriched with nutrients due to the e.g. leaking septic tanks.
In order to reduce the input of nutrients on the reef via sewage water, a water treatment plant is being built on Bonaire. The treatment of sewage water will be extended in 2012 with a sewage system covering the so called sensitive zone, the urbanised area from Hato to Punt Vierkant. Based on the dimensions of the treatment plant and estimated connections to the plant, it can be assumed that a total of 17520- 35040 kg of Nitrogen a year will be removed from the sensitive zone, and will not leach out to the sea at the western coast of Bonaire.
At the moment limited information is available about the total amount of nutrients in the marine environment. Therefore, Rijkswaterstaat Waterdienst asked IMARES to conduct a monitoring study.The goal of this coastal monitoring study was to collect baseline water quality data to be able to study the effectiveness of the water treatment facility in coming years. No estimates are known of the contribution of other sources to the total nitrogen load.
The study consisted of two phases and resulted in two reports:
- recommendations for baseline monitoring in 2011,
- monitoring, data evaluation, and recommendations
The aim of this first report was to define recommendations for the baseline monitoring the, expected positive, impact of the new sewage treatment system on the marine environment of Bonaire, with special emphasis on baseline monitoring. For this an evaluation was made of:
- Parameters/indicators to analyse, including argumentation, critical conditions
- Methods for sampling and critical conditions, including costs
- Potential sampling locations
While the scarcity of up-to-date data on beach litter contamination in the Caribbean has been stressed in several recent studies, we here point to the even greater paucity of published work on litter in mangroves and on the shallow tropical seafloor. During collection of baseline data on beach litter contamination on the Southeastern Caribbean island of Bonaire we also collected preliminary data that may serve to highlight the need for further studies on these largely neglected litter issues.
Marine litter contamination is a wide-spread problem and considered to be one of the most serious threats to sustainable use of the region’s marine and coastal resources. Mangrove litter and shallow submerged litter contamination figure significantly in Bonaire and we have made practical recommendations to help address these problems in a separate report to government. In presenting this synopsis here, we aim to draw scientific attention to these largely neglected facets of the litter problem and hope to see further studies to assess the extent of these problems in the Wider Caribbean.
At St. Eustatius a project has started for the improvement and expansion of the Seaport St. Eustatius. The planned activities related to the project need to be evaluated in order to comply with the legal requirements for a licence from the competent authority Rijkswaterstaat Noordzee in the Netherlands.
A quick scan of the potential environmental impact for the planned activities regarding the St. Eustatius harbour extension was commissioned by Rijkswaterstaat Noordzee. This quick scan was performed within limited time and based upon limited background information. No additional research on site was performed. Consequently, this report provides an environmental impact assessment based only on a review of literature and expert judgement.
Within the project it is foreseen that an estimated 10.000 m3 of sediment will be dredged from the turning basin and dock in the new harbour and from the old harbour. The dredged material will be disposed of in the sheltered inner harbour and south of the breakwater. This deepening of the St. Eustatius harbour and associated activities can potentially negatively impact the environment (directly) through:
- Destruction of habitat on the dredged site and on the site where the dredge material is deposited
- The amount of sediment that will be dispersed into St. Eustatius coastal waters, and the cascading impact thereof on marine habitats
- Noise in marine habitats caused by the placement of piles and moorings
The resulting deepened harbour, the disposal sites and changes in future use may cause long term (indirect) negative impact on the environment due to:
- Dispersal of the dredge spill deposits, and thereby threatening marine habitats
- Increased turbidity due to harbour sediment erosion, increased sediment trapping and more shipping movements
- Changing current and wave patterns, thereby threatening key monuments of human history close to the shoreline
- The increased risk of spills (fuel, oil, bilge water), introduction of nutrients and marine litter, and introduction of invasive species (bio pollution)
These potential impacts have been investigated in this report and have resulted in the following findings:
The tidal and residual currents around St. Eustatius are weak and estimated to be up to 20 cm/s. Near the harbour area, the residual flow is probably dominantly north. The wave height is low throughout the larger part of the year, except during hurricanes and tropical storms. From December to April cold fronts in Florida regularly generate swells from the north to northeast (“brown seas”). These events occur once or twice a month, last for a day to a week, and may generate swell waves 3 to 5 m high.
The marine substrate in the harbour area consists of a hard substratum overlying a more loosely packed conglomerate including sand and pebbles. This hard substratum consists of large rock fragments and cemented conglomerates. Removing this hard layer makes the underlying softer material available for erosion, especially since the deepened area will be exposed to the winter swells and has a water depth where the swells may break (and hence lead to high near-bed shear stresses). The risk for increased levels of suspended sediment due to erosion is probably small, but depends on the fine silt content of the sediment to be exposed. The available information does not indicate the presence of such fine material in the sediment.
During the dredging works, the sediment spill is expected to be limited. It is assumed dredging will be done during calm conditions. Some sediment will enter the water column during dredging, but due to the low ambient currents most will immediately settle from suspension. If present, silt and flocculated mud will be transported 1-2 km northward. Unflocculated mud can be expected to mix with ambient currents within days, leading to only limited increase in turbidity.
Storage of dredged material occurs in the sheltered inner harbour and south of the breakwater. Little dispersion of this sediment is expected during the dredging and storage activities partly due to the planned placement of bubble screens.
Over longer timescales, the removal of the hard layer will probably lead to higher turbidity in the harbour during storms. The winter storms are associated with southward currents, and therefore some of this sediment may be transported south of the wind breaker.
It is expected that deepening of the harbour will lead to a minor change in alongshore transport in the inner harbour, but will not affect alongshore transport north of the old harbour or south of the breakwater. The wave height near the ruins just south of the old harbour will probably increase due to deepening which may have a small effect on the coast.
Based on the above findings and expert judgement regarding sediment transport and turbidity changes the following conclusions are drawn on the potential impact on the environment:
The sediment that enters the water during dredging works is expected to settle relatively quickly, leading to limited sediment-plumes and turbidity. Therefore, no mayor or irreversible impact from dredging works is to be expected on the surrounding habitats. This is based on the assumption that fine silt is not present at the site. However, if these sediments are present, habitats up to 1-2 km north of the harbour can be affected. The impact is estimated, however, to be limited due to the low expected volumes.
Dredging works will impact living organisms at the dredged site and deposit- sites, covering a total area of approximately 1-2 ha (dredged and dredge-deposit site). Recovery is likely to occur over time if environmental conditions permit. This may take up to several years in case of removal of climax stage ecosystems such as coral reefs and seagrass habitats.
Direct impact on marine mammals due to pile driving and placement of moorings are considered to be negligible as the migrating season has already passed and noise levels are considered to be relatively low.
During the deposition of the dredged sediment at the two locations, no impact on surrounding habitats is expected due to the minor dispersion and mitigation measures taken (bubble sheets).
Unless added measures are taken it is expected that the dredge deposit on the south side of the breakwater and south of the old harbour will erode and will be dispersed during storm conditions. The rate at which this deposit will erode, and how much that contributes to overall turbidity during the storm-event, cannot be predicted based on available information.
An adverse impact of the deposited sediment over longer timescales on surrounding habitats cannot be excluded. Erosion of the southern deposit during storm events or hurricanes is likely to occur. This means that it cannot be ruled out that an extra total volume of 7000m3 sediment can be transported towards the southern reserve during a single hurricane event, potentially smothering coral and seagrass habitats. This might lead to severe impact on some species of corals and sea grasses. A significant part of the southern reserve is covered with these species. Current species coverage and abundance is not known, and therefore impact cannot be quantified.
Besides the intrinsic ecological value of the habitats of the southern reserve, the southern reserve holds many important dive sites. The environmental quality of the southern reserve habitats is therefore of high importance to the sustainable economic development and prospects of St. Eustatius. Any risk of deterioration of the southern reserve through resuspension of the dredged material and deposition within the southern reserve should be considered with caution and necessary preventive actions should be taken.
Potential indirect impacts on historical monuments could occur as a result of slightly increased wave heights in the harbour but are expected to be minor.
Indirect impact due to more extensive use of the harbour is expected to be a risk, but hard to quantify. Maintenance dredging is not expected, and if needed, the impact due to sediment suspension will no doubt be less than that of the dredging related to this extension, thus limited (assuming calm conditions and no silt content). Risk of bio-pollution is likely. In order to assess actual impact and proper measures, monitoring should be considered.
Preventive actions should focus on the deposited sediment in the southern corner of the breakwater and lack of information on silt and mud content. Suggestions are to:
- Retrieve information on silt, mud and chalk content in the dredging area
- Make sure sediment deposits cannot erode towards southern reserve. Proper constructions
- should be considered with the contractor and island bureau
- Halt dredging and deposit activities temporarily in case of elevated seawater temperatures
- and during rough seas (to avoid multiple stress)
- Monitor surrounding habitat quality (reefs and seagrass) over time
- Monitor future use and related pressures and mitigate as considered needed