Caves

Este libro es el corolario de muchos años de trabajo y dedicación de los miembros de la RELCOM (Red Latinoamericana y del Caribe para la Conservación de los Murciélagos), cuyo objetivo es poner a disposición de la comunidad los resultados de una actividad de carácter regional, que se viene realizando de manera ininterrumpida desde 2011, cuando el primer AICOM fue reconocido. En 2009, la RELCOM elaboró una “Estrategia para la conservación de los murciélagos en Latinoamérica y el Caribe”, donde se identificaron las amenazas que sufren los murciélagos de la región. Esto despertó la necesidad de crear una figura como grupo para proteger a los murciélagos a través de una propuesta regional. Y es así que surgen las Áreas y Sitios de Importancia para la Conservación de los Murciélagos (AICOMs-SICOMs), inspiradas en las AICAs (Áreas de Importancia para la Conservación de las Aves). El reconocimiento de AICOMs y SICOMs surge como una herramienta para que, de algún modo, pueda ser utilizada por los diferentes países que conforman la red, para orientar los planes de conservación en localidades donde especies y poblaciones de murciélagos se encuentren amenazadas. Si bien no es un instrumento legal, sienta bases para el desarrollo de políticas nacionales y regionales que avancen en ese sentido.

EXECUTIVE SUMMARY

The southern wetlands of Bonaire represent a unique environment for the island. Consisting of a wide variety of habitat types including caves, karsts, dry tropical forests, coastal areas, salt pans and mangroves. The Ramsar site Pekelmeer lies completely in this area, as well as a small portion of the buffer zone of the Ramsar site Lac Bay.

Culturally, a number of Bonaire’s historic monuments and tributes to its past can be found as you drive around the perimeter, from ruins of old salt pans to the remains of slave huts and gravestones. Maintaining and respecting these sober reminders of Bonaire’s history is vital to ensuring the sacrifices of the enslaved populations are not forgotten. It would be impossible to separate the historic and cultural identity of Bonaire from this area.

Economically the southern wetlands represent commercial opportunities for salt extraction by Cargill Salt Works as well as a significant driver of tourism, whether it is history enthusiasts, cyclists, kiteboarders, recreational fishers, scuba divers or bird watchers.

The cultural and economic value of this area is only surpassed by its environmental value. The southern wetlands are recognized internationally as an Important Bird Area (IBA), as a site of regional importance by the Western Hemisphere Shorebird Reserve Network, as an area important for sea turtle nesting and as a Ramsar site. The Ramsar site Pekelmeer, which encompasses most of the southern portion of the wetlands, is critical to a number of threatened, endangered or keystone species. Pekelmeer offers a much-needed rest stop for a number of migratory bird species while also serving as an important breeding ground for the Caribbean Flamingo and five different tern species. Furthermore, the southern wetlands constitute most of the natural habitat of the rare and endemic Bonaire Sabal Palm.

This management plan offers a description of the southern wetlands (chapter 1), a legal and legislative overview (chapter 2), a description of resources and utilities (chapter 3), an explanation of the spatial development plan (chapter 4), an overview of conservation target habitats (chapter 5), an analysis of threats and issues (chapter 6), an outline of management actions and strategies (chapter 7), and provides recommendations for the management plan evaluation and review (chapter 8). Conserving this unique wetland will be a major challenge. A critical first step is to designate Pekelmeer as a protected area under island and national legislation, and appoint a management authority.

Abstract

Bats play key ecological roles on the islands of Aruba, Bonaire and Curaçao (ABC islands), Caribbean Netherlands; however, most bat species on these islands are either threatened or their conservation status is unknown. We investigated the use of roosts by cave-dwelling bats in this insular system to propose conservation measures aimed at their protection. We conducted bi-monthly species inventories of cave-dwelling bats in 13 of the best-known caves and mines used as day and maternity roosts on the ABC islands. Bats were captured with mist nets and a harp trap (only one cave) placed either inside or at the entrance of the roosts during the first hours (3 to 5 hrs) after sunset. For Aruba and Curaçao, bat monitoring comprised two years of sampling. In the case of Bonaire, depending on the cave, bat monitoring involved one, two or four years of sampling. We identified six species of cave-dwelling bats associated with these roosts, Mormoops megalophylla, Pteronotus davyi, Natalus tumidirostris, Myotis nesopolus, Glossophaga longirostris and Leptonycteris curasoae. All the examined caves and mines were occupied year-round. The two abandoned mines were inhabited exclusively by the nectar-feeding G. longirostris and L. curasoae, whereas caves containing hot chambers were occupied by up to five species of bats, including insect-feeding M. megalophylla, P. davyi, M. nesopolus and N. tumidirostris, and migratory L. curasoae. Nursery roosts occupied by insect-feeding bats were Quadirikiri on Aruba; Orizjan, Pos di watapana and Pos di Antoin on Bonaire; and Raton and Noordkant on Curaçao. Nectar-feeding bats used all the caves and mines examined as day roosts, nursery roosts or both. All the cave-dwelling bats studied had a single annual reproductive period. In the case of insectivorous bats, pregnancy and lactation occurred mainly between July and December, overlapping with the rainy season. For nectar-feeding bats, pregnancy and lactation took place between March and September, overlapping with the flowering and fruiting seasons of chiropterophilous cacti. Most of the examined bat roosts require protection due to one or more of the following conditions: (1) the presence of multiple species dependent on hot chambers, (2) their use as nursery roosts, and (3) the presence of large colonies of L. curasoae.

Full text available here: Bat Inventories at Caves and Mines on the Islands of Aruba, Bonaire and Curaçao, and Proposed Conservation Actions (bioone.org)

The Island of Bonaire possess a system of more than 150 natural caves, but only five of them are known to be used as diurnal and maternity roosts by the five species of cave-dwelling bats reported for this island. In the case of Natalus tumidirostris and Myotis nesopolus, Pos di Antoin is the only one. Additionally, this cave is the most important maternity roost known on Bonaire for Glossophaga longirostris and it is also used by all the species of cave-dwelling bats recorded on Bonaire. Its certification as SICOM will become crucial to support and reach the goal of changing its designation status in the Zone Planning to “Natural Area” and/or “Protection Zone-Cave”, in addition of providing this roost with adequate legislation and management plans for its protection. Besides this, its certification will complement the AICOMs and SICOMs already certified on the ABC islands.

The Openbaar Lichaam Bonaire, virtually all nature organizations, private companies and most individuals on Bonaire recognize caves as important features in the landscape and are aware of one or several of their values. Attempts to implement proper protection and management have been conducted with different degrees of success in the past. However, a financially sustainable and efficient management system has not been proposed yet and there is no indication of any significant efforts toward these goals currently ongoing. Successful conservation of caves on Bonaire can only be achieved through the integration of multiple disciplines, institutions and people, organized by means of a strategic plan.

Currently, the ecological, scientific, recreational, cultural and touristic values contained in caves are threatened by uncontrolled activities, both of legal and illegal character. There is virtually a complete lack of management and supervision of the activities happening in the Bonaire caves today. Illegal dumping of solid and liquid waste, uncontrolled visits and “off the record” exploration and documentation efforts by different personal initiatives are a few examples that illustrate this situation. Most importantly, despite their ecological importance, bat populations on Bonaire are threatened by uncontrolled visits to caves that they use as maternity chambers.

Overall Objective

To create the Bonaire Caves and Karst Nature Reserve in order to provide optimum protection and management for the natural, cultural, recreational and scientific values contained in the Bonaire Cave System by September 2019.

Project purpose

• To protect, conserve and restore (if applicable) the natural, cultural, historic, esthetic, recreational and scientific values contained in the cave systems of Bonaire, including, but not limited to, the native flora and fauna, the speleological formations and the ancient inscriptions for future generations,
• To restore the native vegetation of Bonaire,
• To ensure a viable population of 5 keystone species for the island and their ecological interactions,
• To ensure that the residents of, and visitors to Bonaire receive a quality education and information about the ecological importance and protection of caves and the values contained in them,
• To promote and ensure that the resources contained in this cave system are used in a sustainable manner
• To ensure that human safety is given priority during all cave related activities.

Impact project en borging resultaten

For the implementation of the Bonaire Caves & Karst Nature Reserve, the political will of local decision-makers is key. In order to include this implementation on their agenda, lobbying from different sectors is essential, being the most important ones the Dutch Government, universities and research institutions, nature-funding organizations (e.g. WWF, DierenLot and Postcode Loterij), local nature organizations and, last but not least, the local tourism sector guided by the TCB office.

For conducting the necessary research and monitoring of bat populations and other species protected by local legislation inhabiting caves and karst environments (e.g. candle cacti, barn owl, Yellow-shouldered parrot and pearly-eyed thrasher) only funding is needed. The expertise is For conducting the necessary research and monitoring of bat populations and other species protected by local legislation inhabiting caves and karst environments (e.g. candle cacti, barn owl, Yellow-shouldered parrot and pearly-eyed thrasher) only funding is needed. The expertise is locally available and research and monitoring for the species above mentioned are either irregularly ongoing due to lack of funds or a written plan already exists. CARIBSS will propose to implement a fee system, similar to one of the national parks, for the use of these areas. Lastly, for fencing the complete park, only funds are needed as well. Approximately USD 20,000.00.

The Island of Bonaire possess a system of more than 150 natural caves, but only five of them are known to be used as diurnal and maternity roosts by the five species of cave-dwelling bats reported for this island. The Curaçaoan Long-nosed bat (Leptonycteris curasoae) uses all five, but only two of them are used by the Ghost-faced bat (Mormoops megalophylla). Leptonycteris curasoae is one of the two nectar-feeding species responsible for pollination and seed dispersal of columnar cacti in Aruba, Curaçao and Bonaire. This species has been classified as Vulnerable in the IUCN Red List of Threatened Species. Both L. curasoae and M. megalophylla depend on caves as diurnal roosts. Altogether, these attributes reflect clearly the great importance of providing special protection to the caves used by these species. Of the two maternity roosts shared by both species, Kueba di Watapana has demonstrated to be the most important, because it contains one of the largest colonies of pregnant and lactating females of L. curasoae during the reproductive period. Unfortunately, this cave is outside the limits of the protected areas on Bonaire. Its designation as SICOM will contribute to set the basis for adequate management plans and a protective legislation that secures the integrity of this roost and the colonies of L. curasoae and M. megalophylla present in them. The most positive direct impact of this SICOM will be the protection of gravid females of L. curasoae and their newborns. Finally, its designation as a SICOM will complement the AICOM already created.

Elke kenner van de eilanden weet het: Grotten zijn op Curasao niets bijzonders! Al bezoekt ook niet iedereen de grot van Hato, onze meestbekende en indrukwekkendste grot, of, nog minder, die van Fontein op Aruba en Spelonk op Bonaire, met hun merkwaardige
indianenteekeningen — allen kennen de grotten als een opvallend verschijnsel in het Curacaosche landschap, en menigeen zal
zich dan ook hebben afgevraagd, hoe deze grotten toch wel zijn ontstaan en waarom zij zoozeer aan dit landschap zijn gebonden.

Om met de laatste vraag te beginnen. Kalksteen wordt, in vergelijking met de meeste andere gesteenten, gemakkelijk door (koolzuurhoudend) water aangetast. Elk gat, elke spleet waardoor water stroomt, wordt daardoor steeds wijder en kan, op daarvoor geschikte plaatsen, tot het vormen van holen aanleiding geven. De gesteldheid van koraalkalk is daarbij zeer geschikt om een gemakkelijk indringen van regenwater mogelijk te maken — dus is de aanwezigheid van grotten op de eilanden Curacao, Aruba en Bonaire, welke voor bijna de helft met koraal en schelpkalken zijn bedekt, geheel te verwachten.

As pollinators of the typical dry forest cacti, bats are a keystone species. Dry tropical forests are the most threatened type of forest in the Dutch Caribbean due to positioning close to built-up areas. The bats use the many caves as resting habitat. A map of the caves on Bonaire can be found here.

A baseline study on the 9 species of bats of Bonaire (2008-2014) ran across 11 sites and provides information on abundance, sex, weight, size, etc.

Mist netting at caves data:

• Cave use dynamics of cave-dwelling bats in the islands of Aruba, Curaçao and Bonaire
• Population estimates of cave-dwelling bats of in the islands of Bonaire, Aruba and Curaçao

Mark and recapture data:

• Long flights and migratory movements in the South Caribbean of the Curaçaoan Long-nosed bat (Leptonycteris curasoae)

Mist netting, harp traps and ultrasound detector data (bats voice calls):

• Use of habitat types by the bat fauna of Bonaire 

Please contact the DCBD admin, WILD conscience, or STINAPA for more information.

Detailed 3D maps of known Bonairian cave systems.

Caves are especially found in relative soft calcareous rock dissolving and eroding as a result from water and wind. Bonaire exists for roughly 1/3 of volcanic rock and 2/3 of calcareous rock (see geological map). Through time hundreds of dry and wet caves were formed. Cave systems in the Caribbean contain key ecological, cultural, esthetic, scientific and recreational values, including bat resting and  maternity roosts. Bats are a keystone species for dry  tropical forest (see Simal et al., 2015).

Please contact the DCBD admin, WILD conscience, or CARIBBS for more information.

The bat population of the island of Curaçao, Netherlands Antilles, was surveyed in 1992 and 1993. The 1993 survey concentrated mostly on caves, which were found to host most of the bats. Glossophaga longirostris elongata was the most abundant species with fewer than 2000 individuals encountered. However, this species may also be found in small groups in buildings and caves that were not censused. More critical is the status of the other six species found on the island: Leptonycteris curasoae (800–1000), Mormoops megalophylla intermedia (570–650), Natalus tumidirostris (50–60), and three species for which the number of individuals is unknown and probably low: Myotis nesopolus, Pteronotus davyi and Noctilio leporinus. Three caves contain all of the above species, except N. leporinus, and should be actively protected. Two species expected to be present on Curaçao, Artibeus jamaicensis and Molossus pygmaeus, were not found. The apparent decrease in bat numbers this century is likely a result of uncontrolled cave disturbance and removal of resources through development. I propose that all species be considered endangered on the island of Curaçao, except for Glossophaga longirostris, which is threatened.