Terrestial

Abstract:

The aim of the present project–commissioned by the management of the Washington-Slagbaai Park (WSP)- was to set-up a more strategic management of the natural elements of this protected area.

The results are presented in three sections: I. Rare plant species; II. Exclosures and III. Monitoring. The survey of the rare plants resulted in the discovery of three plant species not previously known for Bonaire: Capparis linearis (a tree), Adiantum capillus-veneris (a fern) and a yet undetermined Thelypteris sp.( (a fern). Occurrences were also documented for rare species already known to occur in the WSP. The survey also led to the rediscovery of Capparis tenuisiliqua for the WSPand Bonaire. Brassavola nodosa is reported for the first time for the WSP.

The search for rare plants took place on a number of the higher hills in the WSP. The ‘Matadó di Pasku’ was the hill with the most rare plant species (15). Most of the higher hills in the WSP have a number of denuded areas or areas with scanty vegetation. This is the result of vegetation and soil degradation caused mainly by goat grazing. The negative impact of these animals is also reflected in the almost complete absence of seedlings or other stages of rejuvenation of the rare plants and the exclusive occurrence of the orchid Brassavola nodosa on rock boulders at inaccessible heights for goats.

Isolation of vegetation results in reduction of its dispersal capabilities. As a way to counteract this it is recommended to fence off small areas around the rare tree species identified during the survey. A number of indigenous plant species have been identified that should receive priority in a monitoring and recovery plan: Capparis tenuisiliqua, C. linearis, Schoepfia schreberi, Maytenus tetragona, Eugenia procera, Myrcia curassavica, Psidium sartorianum and Celtis iguanaea. A monitoring protocol is presented to aid in the collection of the data. It has also been recommended to start a propagation program for the orchid species B. nodosa and Schomburgkia humboldtii. The latter was reported in a botanical study in 1994 and must occur in small numbers but could not be relocated. While Sideroxylon obovatum, Guapira fragans and G. pacurero were considered rare in a botanical study done in the WSP in 1994 we did not consider these species rare because they occur quite frequently on the hills visited and are also found in other areas of the island. The results of the present study indicate that it would be valuable to have a botanical survey done of the higher hills of the WSP that could not be visited in the present study.

Three exclosures (9 x 9 m) and three adjacent control plots of the same size (accessible to goats, donkeys and pigs) have been established in the dominant Casearia-Prosopis vegetation type of the D3 landscape type of the WSP. Data collection took place in nine sub-plots of 3 x 3 for both the exclosures and adjacent control sites. The control site was the area of which the vegetation most resembled the vegetation inside the exclosure.

TL7 was the second landscape type in which exclosures and control sites were established. TL7 was chosen above the second most frequent landscape type (D2) of the WSP because its exclosures will provide insight into the development of limestone vegetations and effects of introduced animals (mammals) on them. Limestone vegetations are characterized by dominance of (semi-)evergreen plant species. The sample plots surveyed are characterized by a low number of plant species and high incidence of goat dung pellets.

It is recommended to repeat the data sampling of the exclosures and control sites in two years order to gain insight in the short-term changes in the different vegetation types. Longer-term changes will be seen over a number of years.

To gain a broader insight in natural vegetation development (which will also help to understand development in animal communities) it is necessary to establish several 50 x 50 m permanent plots in (at least) the two most dominant vegegation types in the WSP: Casearia-Prosopis type (D3) and Croton-Haematoxylon type (D2). Because the Slagbaai area will be the first part of the WSP where the goats will be removed, these plots should be placed in this part of the WSP. A data sheet to aid in the data collection (developed by ITC) is presented. A total understanding of the natural development of the vegetation of the whole WSP will be possible through the making of a detailed vegetation map (scale 1:10,000-1:25,000) and repeating it after 20 -30 yrs.

Only one bat species (Glossophaga elongata) is found in the two caves and a well in the WSP. A monthly monitoring program of especially the cave on Seru Grandi is needed in order to determine its significance for G. elongata and possibly other bat species occurring on Bonaire. The easily accessible small cave at Slagbaai should be fenced off to prevent unnecessary disturbance of the bats roosting there by visitors of the WSP.

The monitoring top priorities for bird species are: Buteo albicaudatus, Amazona barbadensis, Sterna hirundo, S. antillarum and Phoenicopterus ruber. Monitoring methods are presented for these species.

No data is available on the impact of exotic plant species in the WSP, but it must be low because invasives were not recorded in any of the sample plots from the park used for the production of the vegetation map of the island and Cryptostegia grandiflora was only seen on the Juwa. In order to be able to control the impact of these species (Cryptostegia grandiflora, Leucaena leucocephala, Azadirachta indica and Jasminum fluminense) they should be monitored. Deleterious exotic animals causing damage in the park at present include goats, donkeys, pigs, cats and dogs. These should be controlled and monitored also. It is therefore recommended to make it a duty of the WSP rangers to report on plant or animal exotic species seen during their patrols and fieldwork. A design for a simple monitoring protocol to record and monitor exotic species is presented. A quick assessment by a biologist of the level of presence of exotic plant species in the WSP will help form the basis of such a program for the exotic plant species and determine the necessary level of interventions by park management. At present there is a trapping program for goats in place using a number of fenced off areas in Slagbaai.

Among the group of remaining animal species three species have been indicated as indicator species for monitoring: Poecilia vandepolii (euryhaline fish), Gecarcinus ruricola (land crab) and Phoebis agarithe (butterfly).

Six habitat types have been distinguished in the WSP: Cave systems, salina habitat, freshwater habitat, vegetation types of Washikemba formation, vegetation types of limestone formations and beach landscape. Their characteristics, occurrences in the WSP, importance for the survival of native fauna and flora species and management and monitoring options are given for these habitat types. 

Abstract:

A preliminary inventory is given of key terrestrial nature values of Bonaire in order to determine their occurrence in relation to areas designated as “nature” and “open landscape”, according to the Spatial development plan of Bonaire. This was based on a literature study and supplemented by expert advice.

In 2010 a spatial development plan was written in order to determine the spatial policy and regulation for the future development of Bonaire. The island was partitioned into areas for different uses such as agriculture and recreation. Two specific designations are “nature” and “open landscape”. The occurrence of nature values within these areas remained unclear. This makes implementation of protective measures based on international treaties and island legislation problematic. An inventory of the occurrence of these values should help facilitate more effective implementation of these protective measures. In the present study key nature values are determined, both in terms of protected species and essential habitat (e.g. caves). 

From the literature study it became apparent that data on the occurrence of most of the priority species of flora and fauna, is limited and scattered, especially with respect to “open landscape” and “nature” outside parks. Therefore, only a preliminary inventory is provided showing the general distribution of nature values across the entire island, as linked to various habitat types. An exact distribution of the different nature values was not possible at this time, but extrapolation from areas of known occurrence into other areas of similar habitat type was used to show the occurrence of overlapping distributions of nature values within the designated areas of “nature” and “open landscape”. The number of overlapping distributions of nature values may contribute to setting conservation priorities.

From the results it can be concluded that the areas of “open landscape” and “nature” (outside the national parks) seem to harbour unique and critical nature values. These areas are not actively managed or protected as national parks. The “open landscape” of Bolivia possibly harbours a few rare plant species (unique), an important population of critical key columnar cacti and at least two columnar cactus-pollinating bat species. The “open landscape” of Washikemba/Bakuna harbours key mangrove species that only have another main location at Lac Bay (national park). The “nature” area of Terrace Landscape Middle Bonaire seems to harbour a concentration of unique (e.g. Tillandsia balbisiana) and rare plant species (e.g. Krugiodendron ferreum etc.) and four bat species. The same is the case for Lima (e.g. Sabal palm, Maytenus versluysii and three bat species) while in Southern Bonaire key mangrove species also still occur. Table 1 shows which nature values are found or expected to occur within each “open landscape” and “nature” (outside national parks) area.

It can be concluded that outside the current parks, the main regions that harbour a concentration of key nature values are Terrace Landscape Middle Bonaire/Sta. Barbara, Bolivia, Washikemba/Bakuna and Lima. Terrace Landscape Middle Bonaire is designated as “nature” area, while Washikemba/Bakuna and Bolivia are in part designated as “open landscape”. Lima has both “nature” and “open landscape” designations. Sta. Barbara is designated for other uses, but the present review shows that the occurrence of several significant nature values is likely within this area.

Additionally, based on the preliminary inventory, the combination of apparent concentrations of rare plants, occurrence of critical bat species and the high probability of corridor values show that the areas of Terrace Landscape Middle Bonaire/Sta. Barbara and Lima are important areas concerning conservation and further research. The areas of Bolivia and Washikemba/Bakuna follow closely.

To be able to implement the necessary protective measures within these areas, it is recommended that more extensive research through fieldwork is done, in order to obtain a complete inventory of the different nature values found on Bonaire, not only in the areas of “nature” and “open landscape” but also in areas with other designations. Additionally, it is recommended to assess the list of vulnerable and endangered species (‘Informatieblad beschermde dier- en plantensoorten Bonaire’) as certain species that may be of importance to Bonaire are not included.

When executing a complete and extensive inventory of Bonaire it would be of value to also determine the ecological conditions needed for the different species to survive. Based on the ecological conditions necessary for their life functions, it may be possible to pinpoint those areas of main ecological importance per species. A complete inventory of the nature values on the island can contribute to better management of nature values (e.g. determining the distribution of caves and the distribution, health status and diversity of keystone cacti species for better management of bat populations). It is also recommended to determine areas with high potential for the occurrence of rare or relict species and which areas harbour high corridor values.

Management Recommendations:

For future research it is recommended to execute a complete and extensive inventory of Bonaire, through fieldwork, in order to implement the necessary protective measures to ensure the conservation of these nature values. The present study shows that the areas of WNSP/Brasil, Terrace Landscape Middle Bonaire, Lima and Bolivia may be of priority as these areas seem to harbour a concentration of unique and critical plants.

Present studies shows that key nature values may occur in areas with a different designation than “nature” or “open landscape”. For future research it is recommended not to limit inventory research to the areas of “nature” and “open landscape”, but to include other areas with different designations.

In the present study the nature values chosen were based on the list of vulnerable and endangered species (Informatieblad beschermde dier- en plantensoorten Bonaire). During the study several species were added based on expert knowledge. The list used therefore seems to be limited. For future research it is recommended to assess if there are other nature values that are important to Bonaire that should be included on the list (e.g. Clusia sp, Ammodramus savannarum).

A complete inventory of the nature values on the island can contribute to the better management of nature values. A good example is the management of Bonaire’s bat population. In order to define the priority areas to maintain for the management of the different bats on Bonaire it is essential to obtain a detailed inventory of the different caves that these species use as habitat.

Additionally for the nectar-feeding bats it is crucial to map the occurrence of the different candle cacti on which they feed. The nectar-feeding bats are the critical pollinators of the three candle cacti (Petit, 2001). As already mentioned these cacti are key species on the island as they provide food for several species of animals during the dry season, when many other plant species are non-productive (Petit, 2001). Research on the distribution, health status and diversity of candle cacti on Bonaire is recommended in order to pinpoint priority areas for nectar- feeding bats. The cactus populations are threatened severely by feral livestock (goats, donkeys) which remove the bark of the mature trees, thereby threatening the food supply for frugivores and nectarivores. From our analysis open land areas of Bolivia would seem to possess large cactus populations of vital interest to conservation of endangered bird species on an island-wide scale.

When executing a complete and extensive inventory of Bonaire it would be of value to determine the ecological conditions and various habitats needed for the different species to survive. Based on the ecological conditions necessary for their life functions it may be possible to pinpoint those areas of principal ecological importance per species.

It is necessary to identify those areas with a high potential for the concentration of nature values rare species or relict vegetation species in order to secure the survival of these species and to be able to implement the necessary protective measurements. Such areas for instance are the open land and nature sections of Lima, Terrace Landscape Middle Bonaire (nature) and Bolivia (open). For future research it is recommended to determine those areas with high corridor values for the implementation of ecological corridors and buffer zones on Bonaire. 

Abstract:

In October 2011 an expedition took place to the Saba Bank, on board of the ship the Caribbean Explorer II. Main aim of the expedition was collecting data on underwater fauna and coral reefs. Apart from that data were collected on nutrients, water flow, sponges and seabirds and marine mammals. Data on the last group were collected by deploying acoustic data loggers, and by means of visual surveys. These visual surveys were conducted whenever the other activities permitted it. This cruise report presents an brief overview of the results obtained during the October 2011 survey. It contains a short day to day report, a full list of all birds, mammals and particular pieces of floating matter seen, and a brief presentation of the results. Furthermore the report contains a brief account of observed birds on Sint Maarten, since published accounts on the birdlife of the island are scarce.

Findings

Seabirds

• The seabirds most often spotted were the Brown Booby and the Magnificent Frigatebird.
• No marine mammals were observed.
• Red-Billed Tropicbirds were primarily spotted near the shore of Saba.

Birds on Sint Maarten

The first ever records of the following birds were made during this expedition:

• Cinnamon Teal (possibility of a hybrid cannot be excluded).
• Marbled Godwit (flying over the Great Salt Pond).
• A Merlin was seen hunting amongst Cliff Swallows and Barn Swallows.
• Three Ospreys were recorded.
• Breeding Caribbean Coots or adults with chicks were seen at several small ponds and in the salines.

Most Common (sighted>10)

• Cattle Egret (Bubulcus ibis)
• Snowy Egret (Egretta thula)
• Magnificent Frigatebird (Fregata magnificens)
• Brown Pelican (Pelecanus occidentalis)
• Black-necked Stilt (Himantopus mexicanus)
• Spotted Sandpiper (Actitis macularius)
• Carib Grackle (Quiscalus lugubris)
• Bananaquit (Coereba flaveola)

Least Common (sighted<2)

• Merlin (Falco columbarius)
• American Oystercatcher (Haematopus palliatus)
• Wilson's Plover (Charadrius wilsonia)
• Short-billed (Dowitcher Limnodromus griseus)
• Wilson's Snipe (Gallinago delicata)
• Marbled Godwit (Limosa fedoa)
• Whimbrel (Numenius phaeopus)
• Solitary Sandpiper (Tringa solitaria)
• Lesser Black-backed Gull (Larus fuscus)
• Cabot's Tern (Thalasseus acuflavidus)
• Eurasian Collared Dove (Streptopelia decaocto)
• Rose-ringed Parakeet (Psittacula krameri)
• Yellow-billed Cuckoo (Coccyzus americanus)
• Green-throated Carib (Eulampis holosericeus)
• Antillean Crested Hummingbird (Orthorhyncus cristatus)
• Northern Parula (Parula americana)
• Caribbean Elaenia (Elaenia martinica)
• Pearly-eyed Thrasher (Margarops fuscatus)
• House Sparrow (Passer domesticus)
• Northern Parula (Parula americana)
• Blackpoll Warbler (Dendroica striata)
• Prothonotary Warbler (Protonotaria citrea)

Notes:

The vessel that was used during this survey was not well suited for dedicated seabird and cetacean surveys. However, the gathered data fits in well with the seasonal pattern in observed seabird species and densities described for Guadeloupe for the same time period (distinct dip from August to October). According to Debrot et al, there are few records of cetaceans in October.

Abstract:

The Important Bird Area (IBA) programme is an initiative of BirdLife International aimed at identifying, monitoring and protecting a network of key sites for the conservation of the world's birds. On the islands, Bonaire, Sint Eustatius (Statia) and Saba, nine IBAs have been designated in recent years. Prior to this study the boundaries of these areas were imprecisely defined and the specific ecological values of these areas were poorly documented and did not provide sufficient footing for further legal protection. In this report we compile available information, add recently collected field data and precisely define boundaries based on ecological and planning criteria so as to furnish the level of documentation sufficient to allow further legal designation and protection by island governments.

In this report we specifically:

• document the most important ecological values represented in each IBA
• define exact boundaries based on ecological and planning criteria and pinpoint core areas that can be distinguished for each IBA 
• discuss the IBA’s spatial context within development and/or land-use plans
• identify potential factors and developments that threaten the long-term spatial and ecological integrity of each IBA
• determine which measures are needed to maintain the spatial and ecological integrity of each IBA.

On Saba one IBA is identified: Saba coastline IBA (AN 006). The 2,145 ha IBA of Saba lacks any form of legal designation as a protected area. Its value is especially based on breeding seabirds, most importantly the Red-billed Tropicbird and the Audubon’s Shearwater. In addition to legal designation, measures needed to protect the values of this IBA include eradication or control of predators such as cats and rats, and management of the garbage dump to limit the number of these predators. On Saba no gaps in IBA coverage are identified.

On Sint Eustatius two IBAs are identified: Boven (AN 007) and The Quill (AN 008). In contrast to Saba, the two IBAs of St. Eustatius enjoy almost full legal designation as protected park areas. Based on our findings we propose an extension of the 1,106 ha Boven IBA to include Signal Hill for its concentration of nesting Red-billed Tropicbirds. The problems caused by cats and rats are much less acute on Statia than on Saba. The value of the 472 ha Quill IBA is largely based on the resident breeding landbirds it supports. Key threats include goats and possibly feral chickens.

On Bonaire six IBAs are identified: Washington-Slagbaai National Park (AN 009), Dos Pos (AN 010), Washikemba-Fontein-Onima (AN 011), Klein Bonaire (AN 012), Lac Bay (AN 013), and Pekelmeer Saltworks (AN 014). The IBAs are designated as “nature” or “open landscape” in the Nature Policy Plan Bonaire spatial plan, thus enjoying protection. 

Washington-Slagbaai National Park (AN 009). (Size: 7,529 ha.) 
The Slagbaai IBA covers a diversity of habitats ranging from coastal lagoons to vegetated hillsides. Key values include its habitat value for Yellow-shouldered Amazon, nesting terns and foraging (West-Indian) Flamingos. Most of the area is legally protected either as an island park or with Ramsar status and actively managed. Key threats include overgrazing by feral goats and pigs. Poaching of the Yellow-shouldered Amazon is also a significant problem. Disturbance of tern colonies also occurs due to inappropriate routing of vehicles close to the important nesting island in the Slagbaai lagoon.

Dos Pos (AN 010) (Size: 293 ha.)
Dos Pos IBA is relatively small and largely has no legal protected status. It is an important freshwater site and is both of importance to resident species of which Yellow-shouldered Amazon is the most threatened worldwide. 

Washikemba-Fontein-Onima (AN 011) (Size: 6,286 ha.)
The Washikemba-Fontein-Onima IBA includes critical habitat for the Yellow-shouldered Amazon, nesting terns and the Caribbean Coot. About half the area is legally designated as either as “Island Park” or “Protected Landscape” in the Nature Policy Plan Bonaire. 

Klein Bonaire (AN 012) (Size: 2,052 ha.)
The Klein Bonaire IBA enjoys full legal protection being designated as a local conservation area and as an internationally recognized Ramsar wetland. The island and surrounding reef are protected within the Bonaire National Marine Park. It is principally of value as a tern nesting island. The woodlands are recovering since complete removal of goats from the island.

Lac Bay (AN 013) (Size: 2,117 ha.)
The Lac Bay IBA enjoys legal designation both as an island conservation area and as international Ramsar wetland site. The mangroves and salt flats are of local significance to nesting terns and hold a breeding population of the Reddish Egret (IUCN-status Near-Threatened).

Pekelmeer Saltworks (AN 014) (Size 6,197 ha.)
The Pekelmeer Saltworks IBA covers about one fifth of the island of Bonaire. Only the 55 ha “Flamingo Sanctuary” and the Pekelmeer enjoy island legal protected status and Ramsar wetland status, while most of the area is used as saliña by the Cargill company. Key IBA values in this area include the nesting colony of the Caribbean Flamingo, and nesting colonies of various tern species. The construction of isolated islands that will not be subject to industrial traffic along the dikes of the managed ponds should provide suitable nesting habitat for recovery of tern nesting in this area of the island. The Laughing Gull population of Bonaire is expanding largely due to the open landfill. This species predates on tern nests and should be controlled if it continues to expand in numbers.

All in all 18 trigger species occur in the nine IBAs in the Caribbean Netherlands. The IBAs on the Leeward islands of Saba and Sint Eustatius host ten and eleven species respectively. Saba is important for the breeding seabirds Audubon’s Shearwater and Red-billed Tropicbird, species with a high conservation priority. The Saba Coastline IBA is the only IBA in the Caribbean Netherlands that qualifies for Audubon’s Shearwater. Saba’s IBA qualifies for another seven species which are all year-round residents with a restricted world’s breeding distribution. St. Eustatius is important for the breeding seabird Red-billed Tropicbird, as well as another eight species: Bridled Quail-dove, hummingbirds and songbirds with a restricted range. The IBAs on the Leeward island of Bonaire host ten trigger species. Some of Bonaire’s IBAs are important for breeding seabird species with a high conservation priority like Royal, Sandwich, Common and Least Tern. Furthermore Bonaire’s IBAs are important for a number of species with a restricted range, of which Caribbean Coot and Yellow-shouldered Amazon have a high conservation priority.

Management Recommendations

On Bonaire several areas are identified that host IBA key species or other ecological valuable bird species and currently are not designated as IBA: 1) Ponds north of Dos Pos; 2) Ponds east of Kralendijk; 3) Urban parrot roosts; 4) Seru Largu. 

This report is part of the Wageningen University BO research program (BO-11-011.05-016) and was financed by the Ministry of Economic Affairs (EZ) under project number 4308701005.

A semi-detailed landscape-based vegetation map (scale 1:50,000) is presented for the southern Caribbean arid island of Bonaire (mean annual precipitation is 463mm). Color aerial photographs (1:8,000) taken in 1995 and 1996 were used to produce the map. A total of 302 vegetation sample plots were analyzed using a stratified random sampling design and twinspan cluster analysis.

A total of 18 vegetation types, and 32 (sub-)landscape types were distinguished. The three principal vegetation types, Casearia tremula-Prosopis juliflora type (Type 17), Croton flavens-Haematoxylon brasiletto type (Type 14) and Prosopis juliflora- Opuntia wentiana type (Type 16), account for 40% of total vegetation cover. The four principal landscape types also cover 40% of the island and are: D3 (Prosopis- Casearia Landscape), TH1(Haematoxylon-Croton Higher Terrace), D2 (Haematoxylon- Casearia Landscape) and TM7 (Acacia-Croton Middle Terrace). The vegetation on the volcanic Washikemba Formation is more uniform than that on the limestone forma- tions. Most of the vegetation types can be categorized as secondary. This is consid- ered mainly to be the result of the impact of introduced grazing mammals (principally goats and donkeys) and woodcutting in the past. Six vegetation types are considered of relatively high natural value. Three of these (Types 1, 9, and 10) are comparable to Stoffers’ less degraded communities. The other three have been selected based on cri- teria such as structural complexity, diversity and number and rarity of rare species.

A comparison with a vegetation map from the 1950’s shows that three types of areas can be distinguished: areas in which the vegetation has remained more or less the same, areas in which the vegetation shows improvement and areas that show broadscale de- terioration of the vegetation. The largest area that shows deterioration is the southern part of Bonaire. The northern part of the Washington-Slagbaai National Park is the largest area with improvement. The findings are discussed in relation to the Nature Management Plan for Bonaire and conservation recommendations are made. 

Management Recommendations:

• Include all the area of Salina Goto and salina Frans inside the borders of WSNP. This expansion will not only benefit the waterbirds but every other native species of flora and fauna as well.
• Pursue the designation of Salina Frans as a Ramsar site for Bonaire.
• Keep collecting data for the long term monitoring programs. It is fundamental for the proper management of our natural resources.
• Provide more training for the staff and volunteers involved in the counts.
• Install permanent depth gauges in all the salinas being monitored.
• Conduct more scientific research for a better understanding of the ecological functions of the salinas as a habitat for water birds
• As resources or time become available, start a monitoring program for the nesting seasons of our resident waterbirds.
• Spread out monitoring areas to include the Salinas in Central and South of Bonaire. 

We document 29 butterfly species for the island of Aruba and 32 for Bonaire. We also document five new records for Curaçao, increasing the total to 58 species. The three islands have inherently similar faunas but those of Aruba and Bonaire are significantly impoverished compared to Curaçao. The decreased diversity is ascribed to human intervention and degradation of the environment.