Bats

Two bat species, Leptonyrteris curasoae and Glossophaga longirostris, are the principal pollinators of at least two of the three species of columnar cacti that grow on the semiarid island of Curaçao, Netherlands Antilles. I examined the importance of the cacti in the diets of the bats and found that 85–91 percent of their diet samples contained cactus pollen and seeds. At least 43 percent of the samples from each species contained cactus pollen andlor seeds exclusively. Leptonycteris curasoae consumes nectar and pollen of Ceiba pentandra and Agave spp. at the beginning of the dry season and G. longirostris also consumes a few other plant products in the wet season, but both bat species depend nutritionally on cacti. Female bats give birth to one pup per year, and the periods of parturition and lactation in each species correspond to peaks in the reproductive phenology of the two most abundant columnar cactus species. From personal observations and a review of the literature, I determined that bats were unlikely to fly to the mainland to feed, although L. curasoae may do so. I conclude that the interdependence of bats and cacti is suggestive of coevolution, and that columnar cacti are critical for the survival and persistence of nectar-feeding bats on Curaçao.

DOI: 10.1111/j.1744-7429.1997.tb00026.x

This month’s issue focuses on the conservation efforts for the Red-billed Tropicbird, which is taking place on the islands of Saba and St. Eustatius. Preliminary studies last year indicated that at two study sites on Saba breeding success was zero. One of the prime culprits appears to be feral cats. All the more reason to bring this species to the spotlight and ask your attention for the plight of this charismatic and locally endangered sea bird.

Amongst others, you will find in this fourth issue:

• Overview of Research and Monitoring Efforts
• Two-way route for Long-nosed Bats between Bonaire and Curacao
• ‘Research of the Month‘: Conservation Science: Red-billed Tropicbirds on Saba and St. Eustatius (by Adrian Delnevo and Hannah Madden)
• TEEB study: “What is St. Eustatius’ and Saba’s Nature Worth?” (by Stijn Schep)
• Nature Policy Plan Caribbean Netherlands published
• Calendar of Upcoming Events, Meetings and Workshops

Data presented herein provide records of four species of bats new to the fauna of the Antillean island of Saba — Monophyllus plethodon, Ardops nichollsi, Tadarida brasiliensis, and Molossus molossus. Together with three species previously recorded from the island – Brachyphylla cavernarum, Artibeus jamaicensis, and Natalus stramineus – the chiropteran fauna of the island is documented to be composed of seven species. Our analysis of species/area relationships for West Indian bats provides a slope value of z = 0.177 and R2 = 0.76; therefore, the bat fauna of the West Indies has the flattest slope for this relationship of any West Indian group. This relationship is best explained by a propensity for over water dispersal by West Indian bats. We propose to unite the chiropteran faunas of the islands of Anguilla, Antigua, Barbuda, Nevis, Saba, St. Barthélemy, St. Eustatius, St. Kitts, and St. Martin by recognizing them as the Northern Antillean Faunal Area. Given the small size of Saba (12 km2) and the even smaller effective habitat for non-molossid bats (4 km2), conservation concerns are expressed for the future of the fauna and some recommendations are made for its preservation. 

The National Nature Policy Plan 2001-2005 (NPP-5) and its current status of implementation was assessed as a first step towards a new Nature Policy Plan for the Caribbean Netherlands (Bonaire, Saba, St. Eustatius). The purpose of this exercise is to determine which action points of NPP-5 are still relevant, and to identify key new developments to be aware of when setting goals and strategies for the new Nature Policy Plan for the Caribbean Netherlands. The NPP-5 was the first formal nature policy plan of the Netherlands Antilles. It lists a total of 47 policy goals and projects in the text for the period 2001-2005. Based on these, 61 action points were listed in an Action Matrix for the period 2001-2005. Of these 31 were achieved to a high degree of completion between 2001 and 2010, notwithstanding the serious and chronic lack of both funds and manpower (NEPP-7). Based on this assessment, a total of 40 action points may be brought forward based on the NPP-5. These not only include most “one-time” action points not yet achieved but also several action points that were achieved but which are of an on-going nature.

While much has been achieved in terms of policy development and legal frameworks over the last 10 years, climate change implies that future nature management will be confronted with an increasingly rapid succession of major ecological problems such as coral bleaching, hurricane impacts, and invading species.

Our quick-scan assessment showed that policy development over the last 10 years has suffered significantly from challenges in terms of both capacity and funding, as well as in decision-making in reaching its goals. Controversial topics regarding “rules and regulations”, “cooperation”, and “financial instruments” largely failed to be achieved due to problems in the decision making process, whereas less controversial action points such as “reporting”, drawing up “plans”, doing “research” and “education”, especially suffered from a lack of capacity and funding.

Several main topics are identified that will need attention in the new nature management plan. The new nature policy will have to meet standard and basic policy needs, information and management needs, and also have to accommodate the latest conceptual developments and the pressing realities of global climate change and alien species invasions. Notable is that a large number of new and serious threats have come to the forefront since the NPP-5 was set 10 years ago.

Because the diverse, colourful and unique natural ecosystems of the Caribbean Netherlands also represent the single most important local economic resource on which to build long-term prosperity of the inhabitants of these islands, the nature policy plan needs to be recognized as much more than simply a way to protect nature and avert ecological crisis. It is in fact a key policy tool by which to actively safeguard and create economic well-being and opportunity for these islands.

A crossword puzzle for children about bats

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.