Bats

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.

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 has a system of natural caves that probably exceeds 150 in number. Those caves house at least five species of bats: Leptonycteris curasoae, Mormoops megalophylla, Natalus tumidirostris, Myotis nesopolus and Glossophaga longirostris. The former four depend primarily or exclusively on caves as diurnal and maternity roosts. The IUCN Red List of Threatened Species considers L. curasoae as Vulnerable. Several studies have underlined the importance of this bat as a pollinator and long-distance seed dispersal agent of several species of succulent plants in northern South America. Likewise, indirect evidence suggests that between December and March part of the populations of Aruba, Curaçao and Bonaire abandon these islands and move to the arid and semiarid zones of Venezuela and Colombia. Until now, we did not know that L. curasoae reproduced on Bonaire, but during the last three years, studies conducted on the island have shown that it is important as a mating and maternity site for the species. At present, we have identified four caves used as maternity roosts. Mormoops megalophylla also reproduces on Bonaire, with at least two maternity caves. Recognition of the Washington–Slagbaai National Park and surrounding areas as an AICOM will contribute to protecting the main habitat types used by all species present on the island as food sources and roosts.

Located in the South Caribbean xeric region, approximately 800 m from the Island of Bonaire, Klein Bonaire is a small flat island (maximum elevation 7 m a.s.l.) with a surface of 690 ha of limestone of coral reef origin and an estimated age of 30.000 to 40.000 years. Free of herbivorous exotic species since the 1980s, it presents a dry thorny forest dominated in the central area by columnar cacti of two species, Stenocereus griseus, and Cereus repandus. These cacti have high production of flowers and fruit, suggesting high foraging activity of the two nectar-feeding bats that live on Bonaire Island, Glossophaga longirostris, and Leptonycteris curasoae. Ecological interactions established between these bats and the cacti (pollination and seed dispersal) are essential for the maintenance of the dry ecosystems present on Bonaire. In addition, the bat pollinated tree Crescenta cujete is also a common species in the plant community. Other species on the island use its fruits. Because of the short distance that separates Bonaire and Klein Bonaire, the second is an important source of food resources for L. curasoae, known to fly over seawater. As natural habitats of Bonaire, including protected areas, undergo a degradation process due to the negative impact of exotic herbivore mammals (goats, sheep, donkeys, and pigs) and the land suffers a fragmentation process due to touristic and urban developments, the importance of Klein Bonaire as food reservoir for fruit bats increases. This island is free of exotic herbivores, and the construction of any type of residential structure is forbidden. Despite being already considered a protected area locally and internationally, its designation as AICOM is important for several reasons: a) it will help enforce future management plans for the island in favor of its wildlife, b) it will influence the approval of future environmental projects on the island (e.g., reforestation, research, recreational activities), c) it will enforce the need to protect the island, d) it will facilitate its designation as a KBA (Key Biodiversity Area) and, e) it will complement the current system of AICOMs and SICOMs recognized for the ABCs.

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.

This action plan for the long-nosed bat describes:

• population status globally declining
• distribution: Occurs in northeast Colombia, north and western Venezuela, Margarita Island, Curaçao, Bonaire and Aruba
• threats (habitat loss due to livestock farming, residential and commercial development)
• management goals
• recommendations (for management, legislation, enforcement, science and monitoring, stakeholders, networking, information-eduction)
• gaps 

There has been a recent increase in public awareness of environmental issues as the effects of climate change have become ever more noticeable in our daily lives. As we enter a new decade, it becomes useful to review what conservation efforts have worked so far, and take inventory of what efforts will be required for the future. Starting with the constitutional referendum creating the Caribbean Netherlands (Bonaire, St. Eustatius and Saba (BES), the response to conservation challenges of all six Dutch Caribbean islands have varied. Since 2010, the BES islands have seen an overall increase in funding support and conservation actions, and therefore presumably also saw greater improvements when compared to Aruba, Curaçao and Sint Maarten, though clearly not enough (Sanders et al, 2019).

The goal of this Transboundary Species special edition of BioNews is to provide an update on the latest published research results and highlight the need for transboundary protection. These species know no boundaries, and thus move between the Dutch Caribbean islands and beyond. Their protection will require broadscale conservation efforts which cover the entire Caribbean, including the six Dutch Caribbean islands. Collaboration between all six islands is of the utmost importance. This is one of the Dutch Caribbean Nature Alliance’s (DCNA) main goals: working together and sharing skills, knowledge and resources to maintain a solid network and support nature conservation in the entire Dutch Caribbean.

Several mechanisms have been shown to influence species richness among island ecosystems, yet most studies limit their focus to a few predictor variables. The objective of this study is to investigate variation in Chiropteran richness across islands in the Caribbean Basin with an extensive set of predictor variables. Using recent faunal surveys, the most contemporary list of bat species per island was complied. Data were collected on 17 predictor variables, which summarized five general island characteristics including island area, isolation, habitat diversity, human impact, and climate. An information-theoretic approach was used by fitting alternative candidate models to determine which variable(s) best predicted bat species richness. Island area and timing of human colonization were most important when islands located on the continental shelf were included in the analysis. When these islands were removed, measures of habitat diversity and climate became the most important predictors for all island groups except the Bahamas, where no variables predicted species richness better than chance. The results of this analysis highlight the importance of island area, habitat heterogeneity, and climate in determining the bat species richness on Caribbean islands.

Key words: area, Caribbean Basin, Chiroptera, climate, habitat diversity, island biogeography, isolation, Mammalia, species richness