Debrot, A.O.

The Caribbean islands of Bonaire, Saba, St.Eustatius, Aruba, Curacao and St. Maarten are part of the Kingdom of the Netherlands. The islands have a rich biological diversity and a variety of globally threatened ecosystems. These ecosystems are important for their services such as the production of food, coastal protection, tourism attraction, erosion control, medicine, carbon sequestration and climate change resilience, water and air purification and/or retention, and non-material benefits such as heritage and recreational experiences. Robust monitoring indicators are needed to assess ecosystem health in relation to environmental change and socio-economic stressors and exploitation.
The Kingdom of the Netherlands has ratified international treaties and conventions, signed regional agreements and implemented national law for the protection of nature and biodiversity in the Dutch Caribbean. These treaties call for reporting on status and trends of biodiversity.
Currently considerable effort is being invested in collecting baseline data and local monitoring to support local policy on and management of nature and biodiversity. These activities partially overlap with the demands of treaty reporting requests, but do not provide all the data necessary to satisfy the needs of either the reporting obligations or the local policy and management needs. The main issues are that:
• Existing monitoring programmes on the islands do not cover all required biodiversity and nature topics;
• Several existing monitoring programmes are based on methods that cannot be used to generate the indicators required.
This report concludes that monitoring all the separate species identified would require considerable resources. Monitoring in the Dutch Caribbean cannot be compared to the Netherlands which has a long history of monitoring the natural environment and many periodic reviews of the efficacy of monitoring techniques. Holistic monitoring of ecosystems using key indicators is a good alternative to detailed monitoring as the ecosystem health implicitly considers all dependent species. However, some additional species monitoring is necessary of keystone species, endangered species, commercially important species and invasive species.
It is recommended to :

• Keep supporting the foolowing current activities: Maintain existing monitoring on: turtle nests, coral, cover, shark and ray densities, flamingo counts, yellow-shouldered amazon roost counts and terns. Adjust the existing monitoring for: fish densities and population structure, bird species richness, red billed tropic bird, Lesser Antillean Iguana;
• Set up ecosystem/habitat monitoring;
• Set up vegetation monitoring;
• Link forest and migratory bird monitoring to vegetation monitoring;
• Link bird of prey monitoring to flamingo monitoring on Bonaire;
• Collect data on pressures and abiotic conditions from other sources ;
• Stimulate the use of volunteers for monitoring

Abstract

The problem of roaming livestock is a major impediment to agricultural development and nature conservation on St. Eustatius, as it also typically is on other islands in the region. In support of a government-led culling program, we here conducted a baseline study of livestock abundance and distribution on the island in the final quarter of 2013. Population density of cattle, goats, sheep and chickens were estimated along 33.5 km of permanent trails, representing six different habitat zones. Each of the 13 trails was assessed five times. The results show overall high densities of chickens, goats and cattle. Clear and statistically significant livestock density differences were found in different zones of the island. The two most ubiquitous species of feral farm animals were goats and chickens which were found in all habitat zones. Island population estimates (± 1 SE) based on habitat-specific detection curves for goats is: N = 2470 ± 807. For chickens, habitat-specific detection-curves were insufficiently distinct to affect population estimates and the island population size estimate for chickens is: N = 2248 ± 668.
Cattle and sheep were more restricted. Our estimate for sheep numbers is only crude 1300 ± 992 and only indicates a minimum count for the island of about 300 sheep. As cattle are large animals and dependent on man-made trails for their movement through the terrain, population size estimates for cattle extrapolated using the Distance approach were found to lead to an excessively high mean population estimate (N = 1012 ± 458). Our best estimate, based on tag-resighting rates for cattle is: N = 600 animals, which does fall within 1 SE for density estimation. So, while the established transects are a useful tool for monitoring livestock density, the counts for cattle should not be used to extrapolate population size.
The density of roaming small ruminants (ie, goats and sheep) are currently at levels considered excessive for sustainable range management in other semi-arid landscapes. Our estimates for goat density per km2 and combined population size for the wooded habitats of the Northern Hills and the Quill where the terrestrial national parks are established are as follows: d = 109 ± 27 and n = (1323 ± 329). Such livestock densities cause soil degradation, loss of organic matter, reduced water retention and erosion in semi-arid rangelands. Therefore the results stress the need to cull, restrict and better manage the roaming livestock herds of the island. Of these, goats are the most problematic due to their habit of preferring steep terrain and cliffs. These are more vulnerable to erosion and harbour higher densities of rare species due to micro-habitat availability.
Complementary counts of cattle by LVV along the same network of trails show that over the last year cattle abundance has not appreciably declined, notwithstanding the ongoing removal efforts. Therefore cattle needs to be removed at a higher rate and/or longer period than achieved to date, to be able to effect a measurable population decline. As a final note we point to the high density of feral chickens on Statia. Chickens are aggressive omnivores capable of impacting small terrestrial animals and seedling regeneration. Their effect, particularly on the rainforest plants and animals of the upper Quill slopes and Quill crater deserves further assessment. 

This deskstudy gives a review of small pelagic fish species and fisheries in the Dutch Caribbean, specifically species which distributions exceed the national boundaries and where international cooperation in research and management is required. The need for this study was recently identified as a high priority action in the 2010 EEZ management plan written for the Dutch Ministry of Economic Affairs. A list of schooling pelagic species with maximum sizes of 40 cm was prepared, based on the occurrence in waters deeper than 200m, in the Dutch Caribbean and Wider Caribbean Area. As a next step the (importance for) the fisheries and biology is described with a focus on the following four species (groups): Sardines (Sardinella aurita), Scads (Carangidae), Anchovy (Engraulidae) and Flyingfishes, in particular Hirundichthys speculiger and Cheilopogon cyanopterus. A fifth group, consisting of clupeids (Clupidae) and halfbeaks (Hemiramphidae) are not truly pelagic because of their association with reefs and coastal distribution, but are locally abundant and important as bait fish.

From a management perspective, small pelagic fish in the Caribbean can be divided into three groups: (1) Species with pelagic behaviour, but coastally bound. 10-20 species, wide spread in the region, locally abundant and targeted as bait fish. This group consists of Carangidae, Clupeidae, Engraulidae and Hemiramphidae. These can be monitored in local sea going surveys because the species are more or less coastal (<less than 20 km). However, catches of small pelagic species are not monitored or surveyed, hence it is often not clear what species are involved. An appropriate survey method to monitor abundance of schooling pelagic fish is echo integration. (2) True pelagic (oceanic) species: all flying fishes, wide spread in the region. Heavily targeted as bait fish, locally for human consumption (Barbados). They are clearly crossing boundaries of EEZ’s in the region. The species involved are wide spread and due to their behaviour difficult to monitor by means of a fisheries independent, sea going survey. (3) Sardinella aurita, off shore distribution, limited to an area of upwelling off the coast of Venezuela. The monitoring of the stock is a Venezuelan appointment, although at the margins, some EEC boundaries are crossed (Columbian, Dutch).

Given the importance for the ecosystem from a Dutch perspective the main focus for further research in the Dutch EEZ, should be given to coastal pelagic species in the pelagic area’s adjacent to coastal reef zones around the archipelagos. This implies no international coordination for this group in the executional phase of the survey. The second group – flyingfishes - requires more international cooperation. This group should be surveyed within ecosystem focussed surveys, running multiple methodologies like visual observations of birds and mammals, biological sampling of fish and hydrographical observations.

The potential for a small pelagic fishery in the Dutch EEZ is discussed. Direct consumption of small pelagic fish, rather than using it in the reduction sector, is more efficient from a biological and an economical point of view. For the Dutch EEZ, as a first step a (bio-)economic study into the potential of the development of a sustainable fishery for small pelagic fish in the Dutch EEZ could be initiated. The flyingfish fishery in Barbados could be used as an example or a reference. Depending on the presence of local pelagic resources, such a study should not merely focus on flying fish but should include all small pelagic fish. The Barbados flying fish fishery could also be used as an example for a local experimental fisheries project.

Finally it is recommended to start collecting data in the pelagic area’s adjacent to coastal reef zones by yearly fisheries independent sea going surveys. The best survey technique for small pelagic fish is fisheries acoustics. However, a holistic approach, incorporating observations of multiple trophic levels, using different strategies within a single survey would be highly preferable. This means that such a survey should be combined with systematic visual observations of seabirds and cetaceans as well as the collection of zooplankton and environmental data. 

Baseline data on anthropogenic seafloor debris contamination in the year 2000 is provided for 24 submersible video transects at depths of 80-900 m, off the Dutch ABC-islands (Aruba, Bonaire, Curaçao), in the southeastern Caribbean Sea. In total, 202 objects were documented from a combined 21,184 m of transect, ranging from sandy lower island-slope to rocky upper island-slope habitat. Debris densities differed significantly with depth. Highest debris accumulation (0.459 items 100 m(-2) or 4590 items per km(2)) occurred at depths of 300-600 m on more shallow-sloping (20-30°) sand and silt bottoms. The overall average debris density was 0.27 objects per 100 m(2) (or 2700 items per km(2)), which is an order of magnitude higher than most other deepwater debris studies. What we describe may be representative for other small, populated, steep volcanic Caribbean islands. Food and beverage-related items were the single largest usage category identified (44% of objects; mostly glass beverage bottles).

The Nature Policy Plan Caribbean Netherlands identifies the need to “Evaluate the financial instruments available for nature conservation in the Caribbean Netherlands and make recommendations aimed at guaranteeing a sustainable financial future” as one of its strategic actions. Three preceding studies investigated budget requirements and sustainable funding of nature (MINA 2000, Spergel 2005, Spergel 2014). These studies focused on the potential sources of income to achieve financial sustainability and led amongst others to the establishment of the trust fund.

The aim of this study by IMARES is to provide insight in the financial needs to carry out park management tasks based on quantifiable tasks. So, rather than the functional approach of earlier studies, which quantified budget needs based on staffing of the park management organizations, we here introduce a task-based approach to identify budget requirements. In this we used elements of the Netherlands cost standards for nature management ('normenboek') to build an analytical calculation model which quantifies the annual budget requirements and human resources based on quantitative estimates of prices for material and labor. The budget requirements were then used to determine the financial gap between financial needs and income sources.

We incorporated the preliminary list of core management tasks recently developed by DCNA and the parks (Appendix A) and re-arranged the list in three levels (responsibilities-tasks-activities). Then we prioritized the four most important responsibilities to achieve the primary goal of nature conservation (infrastructure, education, monitoring, enforcement), merged similar tasks (e.g. monitoring and research) and included additional essential tasks. Furthermore we subdivided tasks in several tangible and quantifiable activities.

Critical monitoring tasks which we also included were a) habitat and species restoration and b) abiotic monitoring. Restoration from losses or damage to habitats and species is part of the primary goal of protecting nature against two major global threats to biodiversity: invasive species and habitat loss and destruction. Abiotic monitoring of factors that influence the abundance or distribution of key species and systems over time (e.g. rainfall, seawater temperature, salinity and water quality) was also included as it is essential to understand ecosystem trends for management purposes.

We further emphasize the importance of infrastructure and explicitly highlighted a number of infrastructure components which we consider essential: a) fences, grids and corrals to keep livestock out and animals in which are essential to protect sensitive habitats and structures; b) freshwater structures which are essential as water supply for flora and fauna; and c) routine maintenance and trimming of mangroves trees which is essential to keep the mangrove channels open.

Based on these prioritizations and extensive cost price information and estimates, the annual budget requirements of the core tasks are estimated at approx. USD 1,461,000 for STINAPA, USD 669,000 for STENAPA and also USD 669,000 for SCF (Table 3.1). The precise calculation of the budget requirements – specified at activity level - can be found in Appendix B.

Three financial gaps were identified: 1) the difference in annual budget requirements according to this study and according to an earlier DCNA assessment; 2) the financial gap in the DCNA trust fund required to start generating returns on investment; and 3) the difference between the annual budget requirements according to this study and the current income sources. With regards to the latter, STENAPA and SCF both have a structural financial deficit between financial needs and income resources amounting to USD 470,000 and 270,000, respectively. STINAPA only has a minor financial gap in 2015 amounting to USD 40,000 due to the financing of overdue mangrove maintenance.

We recommend parties to use the task-based calculation model as designed in this study for future management and fundraising purposes and to plan and justify the activities and budget requirements of the park management organizations. However, the price, cost and activity assumptions made in our calculation model should be validated by a third party and/or by the park management organizations e.g. through a workshop and should be regularly updated. We also recommend a sensitivity analysis of minimum and maximum amounts for different scenarios to be included in the calculation model. Furthermore the calculation model is generally applicable and can also be used and adapted to estimate the budget requirements of park management organizations on Curaçao and St. Maarten, and to calculate the appropriate level of the trust fund capital needed to ensure financial sustainability for nature management for the five participating islands.

Curaçao’s five IBAs—the island’s international priority sites for bird conservation—cover 16,280 ha (including marine areas) and c.24% of the land area. At 13,555 ha the Northeast Curaçao parks and coast IBA (AN015) makes up c.83% of this IBA coverage. The North-east Curaçao parks and coast IBA embraces Curaçao’s two terrestrial national parks (totalling c.2,300 ha). The remainder of the IBA is a Protected Conservation Area, a designation common to part of the Malpais-Sint Michiel IBA (AN016) and the Jan Thiel Lagoon IBA (AN018) although in none of these areas is there active management for conservation. Muizenberg IBA (AN017) is designated as protected parkland, but also suffers from a lack of active management. Klein Curaçao IBA (AN019) is not protected in any way. The IBAs have been identified on the basis of five key bird species (see Table 1) that variously trigger the IBA criteria. Each of these birds occurs in two or more IBAs although the majority of the Near Threatened Caribbean Coot Fulica caribaea occur in the threatened and unmanaged

Muizenberg IBA (AN017).

All of the IBAs have urgent management requirements if the populations of the birds for which they are internationally important are to thrive. However, securing disturbance free

zones around the tern nesting colonies appears to be one of the greatest needs. If implemented effectively, the tern populations would increase dramatically (as seen at the

protected colonies on Aruba) and perhaps some of the 1,200 pairs of “Cayenne” Tern S. sandvicensis eurygnatha that used to breed (pre-1962) at Jan Thiel Lagoon IBA might return.

Monitoring the populations of the terns and waterbirds should be used for the assessment of state, pressure and response variables at each of Curaçao’s IBAs in order to

provide an objective status assessment as well as to highlight management interventions that might be required to maintain these internationally important biodiversity sites.

Retrieved from Birdlife International

Bonaire’s six IBAs—the island’s international site priorities for bird conservation—cover 23,830 ha (including their marine extensions). They embrace c.55% of the island’s land area. Washington-Slagbaai National Park IBA (AN009) and Klein Bonaire IBA (AN012) are formally protected within the national system. Parts of Washikemba–Fontein–Onima IBA (AN011), Pekelmeer Saltworks IBA (AN014) and Lac Bay IBA (AN013) have been identified as proposed protected areas within the Bonaire Nature Management Plan, but these recommendations have not been acted upon. However, the latter two IBAs are designated Ramsar sites, offering them formal recognition of their importance.

The IBAs have been identified on the basis of 10 key bird species that variously trigger the IBA criteria (see Table 1). The majority of these birds occur in two or more IBAs. However, Royal Tern Sterna maxima only nests in Pekelmeer Saltworks IBA (AN014), and the Near Threatened Caribbean Coot Fulica caribaea only occurs on the freshwater reservoirs in Washikemba–Fontein–Onima IBA (AN011). Perhaps of greater concern is the fact that c.60% of the Vulnerable Yellow-shouldered Amazon Amazona barbadensis population occurs outside of formal protected areas, leaving the species totally exposed to capture for the local pet trade. For example, Dos Pos IBA (AN010) contains some of the most important breeding and roosting sites for the species on Bonaire but receives no protection from future development (although there are no immediate threats to this area), or poaching.

There is an urgent need to establish secure, protected areas for breeding terns (Sterna spp.) on Klein Bonaire IBA (AN012), the islands in Goto Lake (IBA AN009) and in the Pekelmeer Saltworks IBA (AN014) through the eradication of cats and rats where possible (e.g. on Klein Bonaire), signage, fencing, and regular patrols. Such proactive management

would likely see a dramatic increase in the breeding tern (and plover Charadrius spp.) populations. More attention should also be given to balancing the management of Pekelmeer

Saltworks IBA for its ecological values in addition to its economic value. Washington-Slagbaai National Park IBA would benefit from a concerted program of removing goats, donkeys and pigs that are so dramatically impacting the vegetation. The landbird (and vegetation) monitoring program started in 2007 should help to determine the impact these grazing animals have had.

Amazona barbadensis would benefit from increased patrolling of the Washington-Slagbaai National Park IBA in an effort to stop poaching, although this would be difficult and costly. More practical would be a public awareness campaign to raise local pride in combination with enforcement of the laws prohibiting the possession of unregistered birds, thereby reducing local demand for wild-caught birds. Ideally this would reach beyond Bonaire to the neighbouring island of Curaçao as a (currently unknown) proportion of parrots poached on the island are exported to Curaçao. Amazona barbadensis on Bonaire is perceived by many as an agricultural pest. A detailed study to determine the extent of agricultural damage caused by the parrot, accompanied by measures to address this conflict with humans is also needed. Further research to determine the factors limiting the parrot

population on Bonaire is required to inform management decisions within the IBAs.

State, pressure and response variables at each IBA should be monitored annually to provide an objective status assessment and highlight management interventions that might be required to maintain these internationally important biodiversity sites.

Retrieved from Birdlife International

A three-year field study (January 2011–December 2013) of the Odonata of Curaçao, supported by photos and exuvial collections, recorded a total of 21 species from the island, almost doubling its previously known fauna. The lists of Odonata known from Aruba and Bonaire were also updated by specimen and photo records, and 24 species are now known from these three islands. During the period of the study, odonates decreased in abundance and diversity in Curaçao, apparently because heavy rains just before the study began led to colonization of the island by several nonresident species that subsequently declined and disappeared as wetlands diminished during a period with normal rainfall.

Outbreaks of Acropora and Diadema diseases in the 1970s and early 1980s, overpopulation in the form of too many tourists, and overfishing are the three best predictors of the decline in Caribbean coral cover over the past 30 or more years based on the data available. Coastal pollution is undoubtedly increasingly significant but there are still too little data to tell. Increasingly warming seas pose an ominous threat but so far extreme heating events have had only localized effects and could not have been responsible for the greatest losses of Caribbean corals that had occurred throughout most of the wider Caribbean region by the early to mid 1990s.
In summary, the degradation of Caribbean reefs has unfolded in three distinct phases:
1. Massive losses of Acropora since the mid 1970s to early 1980s due to WBD. These losses are unrelated to any obvious global environmental change and may have been due to introduced pathogens associated with enormous increases in ballast water discharge from bulk carrier shipping since the 1960s.
2. Very large increase in macroalgal cover and decrease in coral cover at most overfished locations following the 1983 mass mortality of Diadema due to an unidentified and probably exotic pathogen. The phase shift in coral to macroalgal dominance reached a peak at most locations by the mid 1990s and has persisted throughout most of the Caribbean for 25 years. Numerous experiments provide a link between macroalgal increase and coral decline. Macroalgae reduce coral recruitment and growth, are commonly toxic, and can induce coral disease.

3. Continuation of the patterns established in Phase 2 exacerbated by even greater overfishing, coastal pollution, explosions in tourism, and extreme warming events that in combination have been particularly severe in the northeastern Caribbean and Florida Keys where extreme bleaching followed by outbreaks of coral disease have caused the greatest declines.
 
In: Status and Trends of Caribbean Coral Reefs: 1970 - 2012. Jackson, J.B.C., Donovan, M.K., Cramer, K.L. Lam, W.. - Washington : Global Reef Monitoring Network, 2014 - p. 211 - 215.
 
Retreived from http://www.wageningenur.nl on April13, 2015

Outbreaks of Acropora and Diadema diseases in the 1970s and early 1980s, overpopulation in the form of too many tourists, and overfishing are the three best predictors of the decline in Caribbean coral cover over the past 30 or more years based on the data available. Coastal pollution is undoubtedly increasingly significant but there are still too little data to tell. Increasingly warming seas pose an ominous threat but so far extreme heating events have had only localized effects and could not have been responsible for the greatest losses of Caribbean corals that had occurred throughout most of the wider Caribbean region by the early to mid 1990s.
In summary, the degradation of Caribbean reefs has unfolded in three distinct phases:
1. Massive losses of Acropora since the mid 1970s to early 1980s due to WBD. These losses are unrelated to any obvious global environmental change and may have been due to introduced pathogens associated with enormous increases in ballast water discharge from bulk carrier shipping since the 1960s.
2. Very large increase in macroalgal cover and decrease in coral cover at most overfished locations following the 1983 mass mortality of Diadema due to an unidentified and probably exotic pathogen. The phase shift in coral to macroalgal dominance reached a peak at most locations by the mid 1990s and has persisted throughout most of the Caribbean for 25 years. Numerous experiments provide a link between macroalgal increase and coral decline. Macroalgae reduce coral recruitment and growth, are commonly toxic, and can induce coral disease.

3. Continuation of the patterns established in Phase 2 exacerbated by even greater overfishing, coastal pollution, explosions in tourism, and extreme warming events that in combination have been particularly severe in the northeastern Caribbean and Florida Keys where extreme bleaching followed by outbreaks of coral disease have caused the greatest declines.
 
In: Status and Trends of Caribbean Coral Reefs: 1970 - 2012. Jackson, J.B.C., Donovan, M.K., Cramer, K.L. Lam, W.. - Washington : Global Reef Monitoring Network, 2014 - p. 55 - 154.
Retreived from http://www.wageningenur.nl on April13, 2015