In this report we review and assess possible consequences of climate change for the biodiversity of the Dutch BES islands (Bonaire, Saba and St. Eustatius), and present various options for adaptation. From our review it is quite clear that climate change not only poses a severe threat to the ecosystems of the BES islands, but also to the totality of benefits and services the inhabitants of these islands derive from those ecosystems. Key changes in climate expected this century include increases in air and sea surface temperature, an increase in sea level and ocean acidity, an increase in the frequency and intensity of storms and hurricanes, general aridification and greater overall unpredictability in weather. The consequences for both terrestrial and marine biodiversity are predicted to be far-reaching. The principal effects will likely include further losses to the coral reef systems, erosion of coasts and beaches, salinification of ground water sources, losses in hilltop vegetation and flora, soil humus losses and erosion, increases in various disease vectors, changes in ocean currents, fish recruitment and migration, and a stronger foothold for invasive species.
The main areas of environmental policy involving the management of biodiversity are those of land-use planning and zoning, forestry and terrestrial conservation, and marine conservation. As for land-use planning and zoning, main issues of concern will be the introduction of the 'set back' policy for coastal development, the preservation of the full range of key habitats, and sufficient habitat surface area to sustain minimum viable populations for native species. In addition these habitats must be ecologically connected to allow free movement of animals across the habitats they need throughout the different seasons of the year and phases of their life cycle. In terms of forestry and terrestrial conservation policy, the focus will especially need to be on solving the problem of uncontrolled grazing of livestock, and the implementation of reforestation and groundwater conservation. Key issues in marine conservation policy will be to tackle the technically and financially challenging problem of eutrophication and the socially controversial limits to the harvest of reef organisms.
While it is the large industrialized countries that drive man-induced climate change, it is the small island developing states (SIDS) and small coastal states that will suffer the most from climate change. In this respect it may be especially valuable for the BES islands to develop and participate in larger efforts to convince (pressure, lobby) the large industrialized nations to adopt those changes needed in their industrial and energy policies by which to avert the most disastrous scales of global climate change. As the stakes are obviously very high, the BES islands should seek to actively develop and/or participate in such efforts. However, to do this credibly and convincingly will require the islands to develop their own vision and policy and to implement important measures of their own. While the topic of climate change has recently come to the attention of government, preparation and readiness for climate change lags behind.
The main options for local adaptation measures as outlined all come down to just one principle: to 'manage for resilience' of the ecosystems as much as possible by reducing the stress induced by local anthropogenic pressures. This will require proper data and knowledge as well as a proper monitoring of impacts and results. In this, investment in baseline inventories, dedicated research and a monitoring system is essential.
If international resolve falters and precipitous global climatic change cannot ultimately be avoided, large ecological regime shifts may cause ecosystems and species in any given area to become ecologically untenable, and introduced species to become firmly established and impossible to eradicate. If so, it will be important to make hard choices and not waste valuable time and resources fighting lost causes. Therefore, in the future successful management of natural resources will often require managers and decisions makers to think differently than in the past, to abandon old paradigms and objectives, and to focus more on general ecosystem services than on specific details. Hence our ability and willingness to adaptively 'manage for change' will be critical, as will be the need for effective decision making under conditions of complexity, uncertainty and imperfect knowledge.
Doel en achtergrond werkbezoek
Sinds 10 oktober 2010 maken Bonaire, Sint Eustatius en Saba deel uit van Nederland. Rijkswaterstaat heeft wettelijke verantwoordelijkheden voor deze eilanden. Hieronder valt het opzetten van een operationele maritieme incidentenorganisatie. Gezien de enorme olie-overlagbedrijven op Sint Eustatius en Bonaire, de economische afhankelijkheid van de eilanden van duik toerisme en gezien de biodiversiteit in (de zeeën rond) Caribisch Nederland is dit geen overbodige luxe. RWS Noordzee zet de incidentenorganisatie op. De landelijke coördinatiecommissie milieuincidenten (LCM) ondersteunt hierbij. Doel van de reis naar Caraïbisch Nederland (CN) was om te komen tot een advies over de olie-bestrijdingsmogelijkheden, waaronder mechanisch opruimen en het gebruik van detergenten.
Bij oliebestrijding is de keuze voor de wijze van bestrijding belangrijk. Het standaard uitgangspunt van de oliebestrijding is het verwijderen van de gemorste olie uit het milieu (mechanisch opruimen). Gedurende de reis is geïnventariseerd welke middelen beschikbaar zijn en wat noodzakelijk is om de opruimcapaciteit op het afgesproken niveau te brengen (tier 1, 16 m3).
Er zijn situaties waarbij de inzet van detergenten kwetsbare kustzones kan beschermen. Om het gebruik van detergenten te ondersteunen is een beslisboom detergenten beschikbaar. Voor het Caraïbisch beheergebied moet deze beslisboom worden aangepast. Voor het toepassen van detergenten is het van belang inzicht te hebben in de verspreiding van olie op zee. In Europees Nederland wordt gebruik gemaakt van het operationele model oilmap. Voor CN is het van belang dat dit model ook ingezet kan worden.
Het advies is gericht op het beperken van de belangrijkste risico’s en op maatregelen die op korte termijn gerealiseerd kunnen worden.
The Netherlands are signatories of the international Convention on Biological Diversity (CBD). This implies that the nation will protect biodiversity on its territory. This includes the protection of natural fauna and vegetation from negative impact caused by invasive alien species (see 2.1. for a definition). By 10-10-2010 the BES islands (Bonaire, St Eustatius and Saba) became ‘special municipalities’ of the Netherlands. They together form “Caribisch Nederland” (Caribbean Netherlands, Hulanda Karibe). Due to this stronger link to the Netherlands many responsibilities have moved from the Antillean government to the Netherlands. This includes important responsibilities with respect to the protection of nature.
The present study was financed by the Dutch Ministry of Economic Affairs, Agriculture and Innovation and included a literature study, a field trip and writing of the present document with main observations, conclusions and recommendations. A major part of the report consists of an alphabetical list of (known) invasives with their current status (4.1.1.). Apart from the three islands belonging to Caribisch Nederland, for completeness, some attention is given to Aruba, Curacao and St. Maarten as well (esp. in 4.1.1. and Appendix II).
Stages of invasion
In order to define the problem of invasive alien (non-native) species of plants more accurately it is relevant to recognise the following categories:
Exotic: Species that are not part of the natural indigenous vegetation are called exotics. Examples are introductions as ornamental or agricultural species. If contained within the confines of gardens and farms, these species are not considered problematic.
Established: Species that occur ‘in the wild’, i.e. outside the control of cultivation or husbandry and are able to reproduce themselves resulting in new individuals, we call established (present). Species can stay in this phase, the ‘lag phase’ (see 2.1), for quite some time. It is the stage in which the species adapts to its new environment using its genetic flexibility. At this stage complete eradication is still an option, because the number of individuals and locations is limited. This means that the costs can be relatively low, compared to eradication at a later stage.
Naturalised: If given enough time, species may start to adapt genetically to the new environment, by optimising its physiology and/or growth habit. As a result the species will start spreading more rapidly and effectively and becoming part of the natural flora. In most cases this is not considered a major problem; the plants will get their own function within the ecology of the island and will not replace indigenous species entirely. Moreover, the costs of complete eradication have become prohibitive at this stage, so only containment is an option.
Invasive: It is generally believed that about one in one thousand exotics becomes really problematic, e.g. with respect to environmental, ecological or economical impact (Williamson 1995). They start to grow out of control, massively invade natural habitats and reduce or eliminate native species. They have broken down the dispersal barrier and have become invasive. At this stage one can only try to achieve a stage of equilibrium, of mitigation, by intensive control measures. These are usually limited by financial resources, and can normally only be successful with commitment of the local society, e.g. shown by the enthusiastic support and hand labour of many volunteers.
Invasives of the Caribbean Netherlands
In this report 65 species of invasives are enumerated (4.1.1.) with their history and properties, based on a literature survey and completed with experience and findings of the authors. Four of the main problematic species are treated more extensively in 4.1.2. These are the Coral vine (Antigonon leptopus) which poses a great threat to nature, especially in St. Eustatius; the Rubber vine (Cryptostegia grandiflora) which is able to overgrow and smother shrubs and trees and is especially spreading on the Leeward Islands; the neem tree (Azadirachta indica) which is planted for shade and medicinal purposes, but is escaping on Bonaire; and ‘Donna grass’ (Bothriochloa pertusa) which is a very problematic species replacing the more palatable local grasses on the Windward Islands, most notably on St. Eustatius.
In a complementary list a further 80 species that need more investigation are mentioned (4.1.3.). This list is not complete but it enumerates species that are present on at least one of the islands. They need special attention because it is best to prevent them from entering at all or to eliminate the few plants or populations that have established themselves. Some species in this list are already present at some scale, like some of the arable weeds, but need careful monitoring to prevent them from entering nature.
A general problem are the free-roaming animals, cows, donkeys and especially goats (all non- native species) that are destroying nature in an uncontrolled way. Their presence has a detrimental effect on biodiversity, eating young seedlings and trees, and thereby preventing the natural regeneration and succession. Moreover, the bare soils that result are susceptible to water and wind erosion; material that is deposited in the surrounding seas.
Before an exotic has been introduced prevention is the most important action, i.e. keep the chance that exotic species may be introduced as low as possible. As soon as a first introduction has been realised and the exotic still occurs at low densities at few sites, eradication after first observation will be the most important action. Finally, if an exotic has already spread over different sites or even different habitats and has increased in densities, eradication might not be an achievable option anymore. Then containment and population management will be the most relevant actions to minimise the negative impact (mitigation). In general, prevention will generate the most cost-effective options to avoid problems due to invasive exotic plants (Davis 2009). The main observations are:
Prevention: Prevention plans need to be developed with regulations restricting the import of exotic species. This includes the development of ‘Black lists’ for the Leeward and Windward Islands respectively. Public awareness (customs and other officials, general public, landscapers, new inhabitants) must be raised and alternatives for imported exotics must be offered. Agricultural departments and customs offices on all islands are understaffed and not able to control the many routes through which exotics enter.
Eradication after first observation: Rapid first observation of an exotic plant after introduction into the wild is essential for the success of an eradication action. Therefore a ‘Watch list’ or ‘Grey List’ needs to be developed. Since the difference in climates, these watch lists will partly differ between islands and differ even more between the Leeward and Windward islands. Also knowledge about the natural flora and invasives must be increased through education, at schools as well as for professionals (rangers, customs personnel, agricultural department, etc.). Floras for the Windward Islands are outdated and not accessible.
Containment/population management: Management plans need to be developed for the control Antigonon, Cryptostegia and neem to be able to stop further spreading and to mitigate the impact on nature. Research on the life cycle of invasives and experiments for their control have to be carried out. The problem of roaming animals must be tackled. Small island communities are not able to do this without outside assistance. If chemical control is considered, special Dutch Caribbean regulations apply based on restricted import permissions for crop protection agents.
Ocean acidification (OA) refers to the ongoing decline in oceanic pH resulting from the uptake of atmospheric CO2. Mounting experimental evidence suggests that OA will have negative consequences for a variety of marine organisms. Whereas the effect of OA on the calcification of adult reef corals is increasingly well documented, effects on early life history stages are largely unknown. Coral recruitment, which necessitates successful fertilization, larval settlement, and postsettlement growth and survivorship, is critical to the persistence and resilience of coral reefs. To determine whether OA threatens successful sexual recruitment of reef-building corals, we tested fertilization, settlement, and postsettlement growth of Acropora palmata at pCO2 levels that represent average ambient conditions during coral spawning (∼400 μatm) and the range of pCO2 increases that are expected to occur in this century [∼560 μatm (mid-CO2) and ∼800 μatm (high-CO2)]. Fertilization, settlement, and growth were all negatively impacted by increasing pCO2, and impairment of fertilization was exacerbated at lower sperm concentrations. The cumulative impact of OA on fertilization and settlement success is an estimated 52% and 73% reduction in the number of larval settlers on the reef under pCO2 conditions projected for the middle and the end of this century, respectively. Additional declines of 39% (mid-CO2) and 50% (high-CO2) were observed in postsettlement linear extension rates relative to controls. These results suggest that OA has the potential to impact multiple, sequential early life history stages, thereby severely compromising sexual recruitment and the ability of coral reefs to recover from disturbance
Data on beach debris and tar contamination is provided for 21 natural beach sites in Bonaire, Southeastern Caribbean. Transects amounting to a combined length of 991 m were sampled March–May 2011 and a total of 8960 debris items were collected. Highest debris and tar contamination were found on the beaches of the windward east-coast of the island where geometric mean debris concentrations (± approx. 70% confidence limits) were 115 ± 58 items m-1 and 3408 ± 1704 g m-1 of beach front. These levels are high compared to data collected almost 20 years earlier on the nearby island of Curaçao. Tar contamination levels averaged 223 g m-1 on windward beaches. Contamination levels for leeward west-coast beaches were generally two orders of magnitude less than windward beaches.
Coral reefs worldwide are attracting increasing numbers of scuba divers, leading to growing concern about damage. There is now a need to manage diver behaviour closely, especially as many dive companies offer unlimited, unsupervised day and night diving from shore. We observed 353 divers in St. Lucia and noted all their contacts with the reef during entire dives to quantify rates of damage and seek ways of reducing it. Divers using a camera caused significantly more contacts with the reef than did those without cameras (mean 0.4 versus 0.1 contacts min-1), as did shore versus boat dives (mean 0.5 versus 0.2 contacts min-1) and night versus day dives (mean 1.0 versus 0.4 contacts min-1). We tested the effect of a one-sentence inclusion in a regular dive briefing given by local staff that asked divers to avoid touching the reef. We also examined the effect of dive leader intervention on rates of diver contact with the reef. Briefing alone had no effect on diver contact rates, or on the probability of a diver breaking living substrate. However, dive leader intervention when a diver was seen to touch the reef reduced mean contact rates from 0.3 to 0.1 contacts min-1 for both shore and boat dives, and from 0.2 to 0.1 contacts min-1 for boat dives. Given that briefings alone are insufficient to reduce diver damage, we suggest that divers need close supervision, and that dive leaders must manage diver behaviour in situ.
My thesis research builds on the ‘movement’ to value nature. This movement as I call it started as early as 1970 with a theory to quantify and monetize nature (Hueting, 1970). References to the concept of ecosystem services date back to the mid 1960s and early 1970s (de Groot et al., 2002). A Phd research into the value of nature by De Groot (1992) emphasized the need to “ecologize” economic valuation of ecosystem services by integrating ecological information.
In 2005 the Millenium Ecosystem Assessment (MEA) report used the ecosystem services approach to highlight the importance and drivers of changes of ecosystem service delivery (MEA, 2005). The Economics of Ecosystem services and Biodiversity (TEEB) platform built on the framework of MEA, but specified ecosystems in underlying functions, processes and structures to “ecologize” economic benefits of biodiversity and costs of biodiversity losses (TEEB, 2010a).
Valuation of ecosystem services can be done at three levels, monetary, quantitative and qualitative. Qualitative describes benefits in a non-numerical scale, quantitative measures benefits and changes based on numerical data and monetary builds on quantitative value and attaches a monetary value (White et al., 2011). This research is a semi-quantitative analysis of the functional value of coral reef habitats on Bonaire to support ecosystem services. It is part of an economic valuation study of marine and terrestrial ecosystem services on Bonaire. The economic valuation study estimated a monetary value of selected ecosystem services. My research measured the functional value, defined as the ecological importance of a habitat, on an ordinal scale with four levels (0-3).
The TEEB theoretical framework was applied by studying the underlying ecological functions, processes and structures of coral reefs that determine the capacity to deliver coral reef ecosystem services through a literature review. The functional group approach was used as a measure of the importance of habitats based on the level of representation of fish and coral functional groups. The methodology to analyze the functional value was inspired by a study of Harborne (2006) that established the functional value of Caribbean coral reef, seagrass and mangrove habitats to ecosystem processes.
My research applied this method using Bonaire as case study and adapted the method to determine the functional value of habitats to ecosystem services instead of ecosystem processes. This way the study of Harborne has been taken a step further by making the link between the economic analysis focussing on ecosystem services and the ecological analysis focussing on ecosystem functioning. The other adaptations made were the spatial scale, the habitat types and the data collection method. Harborne determined the value by doing a meta-analysis of empirical literature on processes in ten coral reef, seagrass and mangrove habitat types.
For my research primary data of fish and benthic functional groups were collected at over hundred locations along the entire leeward coast of Bonaire to value just two coral reef habitat types.
Outcome of this research are matrices presenting relationships between socio-economic services and ecological functions, processes and fish and benthic species representing a functional role. Another outcome are maps presenting the functional value of each location to support twelve ecosystem services based on the primary data collected. These maps were analyzed taking into account resource use on Bonaire and show which area are of high importance for each service.
This research is innovative in its attempt to link the economic value of ecosystem services with an ecological value of habitats to support these ecosystem services. In addition the survey of benthic cover and fish biodiversity and abundance has not been done at such a large scale according to our knowledge since the mapping of Bonaire in 1985 (Van Duyl, 1985).
This report contains a study regarding the biodiversity of the Saba Bank, one of the three largest atolls in the world. All scientific and anecdotic evidence suggests that the area is a hot spot of biodiversity and one of the few areas in the Caribbean that is still in a relatively pristine condition. The atoll is likely also important as a source of larvae for other areas in the region because of its enormous dimensions and diverse habitats. Major damage however may already be inflicted by the anchoring of large oil tankers. More scientific research is necessary with regards to the damage inflicted by anchoring and to the sustainability of current fishing practices, but to date there is already sufficient data to call for strong protection of the Saba Bank as soon as possible.
Therefore, an application to the International Maritime Organization (IMO) to designate the Saba Bank as a Particularly Sensitive Sea Area (PSSA) in order to prevent possibly irreversible damage to the ecosystem and to enable sustainable protection of it’s vulnerable resources seems crucial and urgent.
This research is performed within ‘Beleidsondersteunend Onderzoek’ (BO-11), cluster NLP of LNV-programs.
The main conclusion from this study is that the Saba Bank is a hot spot of biodiversity and one of the few areas in the Caribbean that is still in a relatively pristine condition. The Bank is likely also important as a source of larvae for other areas in the region because of its enormous dimensions and diverse habitats.
- Scientific evidence that the Saba Bank constitutes a major hot spot in marine biodiversity in the Caribbean region has strongly increased over the last couple of years and is now overwhelming.
- All studies to date express surprise and wonder at the number of different habitats and species within the Saba Bank.
- With limited sampling effort new species have already been found within the Bank and more are to be expected.
- The Bank is likely be one of the very few places in the Caribbean that as yet has largely escaped human related pressures and may still be considered as being in a relatively pristine condition.
There is to date already sufficient data to call for strong protection of the Saba Bank as soon as possible. Designating the Saba Bank as a Particularly Sensitive Sea Area (PSSA) in order to prevent possibly irreversible damage to the ecosystem and to enable sustainable protection of its vulnerable resources seems crucial and urgent.
- Study the effects of fishing to ensure that it remains at a sustainable level.
- Draft and implement a management plan as soon as possible. At present anchoring outside the 12 miles zone is not regulated and anchor damage could be devastating to the whole ecosystem.
- Carry out more research about the ecological processes of the Saba Bank so as to protect it in the most effective way.