Bats

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.

To inform decision makers about the most effective strategies to protect the ecosystems of Bonaire, a full-scale valuation of all ecosystem services on the island of Bonaire has been undertaken by WIKCS and the VU University Amsterdam. The study addresses a wide range of ecosystems, ecosystem services and applies a multitude of economic valuation and evaluation tools. For budgetary reasons, a distinction has been made in terms of the ecosystem services covered by the studies between ecosystem services that are valued through primary research and ecosystems services that are addressed through secondary data analysis. This report summarises the ecosystem services that are valued on the basis of desk research or through key informant interviews. The quality of each sub-study varies, depending on the data availability to the subsequent researchers. This also implies that not each sub-study was able to actually generate a monetary value to be included in the Total Economic Value (TEV) estimate. Despite this caveat, the individual studies increase the understanding of the complex links between nature and society on Bonaire and are therefore worth presenting.

Art value

Artists are inspired by their surroundings. Such is also the case on Bonaire, where the natural scenery of the island stimulates artists to use components of nature in their work. Clearly, nature plays a crucial role in the production process of art on Bonaire. The demand of art consists of the thousands and thousands of tourists visiting the island, who are keen to bring home a piece of art to memorise the beauty of the island upon their return. Moreover, the beautiful photographs and books produced on Bonaire are distributed to clients across the world. Given the explicit demand and supply of art on Bonaire and its strong dependence on nature, the art sector on Bonaire plays an important role in the overall economy and provides an additional reason to manage nature well on the island. The value of the ecosystem service of artistic inspiration is valued at $460,000 annually.

Research value

Nature in Bonaire provides important services for research and education. The marine and terrestrial environment of Bonaire is subject for a large group of academics who conduct and publish innovative research based on these unique and easily accessible ecosystems. Without the presence of healthy ecosystems, Bonaire would not attract large numbers of researchers nor would Bonaire’s nature be a source of inspiration for many educational activities on the island and beyond. This sub-study made an inventory of all ecosystem related research expenditures funded by governmental and non-governmental organisations for Bonaire. In total a total research value was estimated between 1,240,000 USD and 1,485,000 USD in 2011.

Medical and pharmaceutical value

Medicinal plants play important roles in many traditional societies. The healing properties of herbal medicines have been recognized in many ancient cultures thousands of years ago. Besides these local benefits, biodiversity is important for the development of pharmaceutical treatments and drugs. The purpose of this sub-study is to economically value the benefits of species and ecosystem functions that are relevant for medicinal and pharmaceutical purposes. The study found that a large part of the population in Bonaire regularly collects and uses local herbs and other medicinal plants for medical treatment. Two-third of the inhabitants who were surveyed made use of local plants as an alternative to modern medicine or prescription drugs. Ultimately, a total annual medicinal and pharmaceutical value results of $688,788 of which more than half is comprised of the local value of medicinal plants.

Carbon sequestration

The ecosystem service of climate regulation deals mainly with greenhouse gas emissions and how ecosystems can mitigate such effects. Bonaire has six ecosystems that provide carbon-sequestering properties: salinas, dry forest, coral reefs, sea grass, mangroves and open ocean. The objectives of this sub-study is to (1) identify the ecosystems that are relevant to climate regulation in Bonaire with their functions and threats; (2) describe the different economic valuation methods suitable for climate regulation calculations; and (3) value the overall climate regulation potential of Bonaire. This desk study has made a rough attempt to estimate the carbon sequestration value of the main ecosystems of Bonaire. Based on carbon market prices at the time of research, this value was estimated at $290,000 per year.

Pollination by bats

The island of Bonaire is a fauna and flora rich and beautiful attraction in the Caribbean. By supporting fruit growth and aesthetic values, bats plays an important role in preserving high levels of biodiversity on Bonaire. This study made an attempt to give more insight in the importance pollination by bats for the island. Due to limited availability of data and time, the study will not generate an actual economic value of pollination. Yet, by describing the possible links between pollination and the economy of Bonaire, this study adds value and provides a solid foundation for an actual economic valuation study in the future. Despite of the lack of a concrete economic value, the evidence provide support the notion of conservation of the bats of Bonaire their natural habitat (i.e. caves). Both economic and cultural reasons have been identified to support this conclusion.

Coastal water quality

This paper attempts to examine the values of ecosystems in provisioning good water quality in Bonaire, Dutch Antilles. Bateman’s (2011) steps in ecosystem assessment and economic analysis are used as a framework to run this examination. Three ecosystems are identified that contributes to deliver services in question: mangroves, saliñas/salt marshes, and sea grasses. Based on their functions related to providing good water quality (filtering, water purification, and nutrient cycling) this report proposes three valuation methods: 1) replacement cost method for mangroves and saliñas; 2) Production function method for sea grasses. Benefit transfer also mentioned in the discourse to tackle the challenge of finding relevant data.

Amenity value

The fact that many people prefer natural over built environments is often manifested in house prices. Therefore various environmental conditions may have a significant impact on house prices. In Bonaire these include the view or proximity to water bodies, coral reefs and other healthy ecosystems. This study aims to estimate this so-called amenity value of nature on Bonaire. Through a hedonic pricing analysis, the hypothesis was tested whether property values are not only determined by conventional house and neighbourhood characteristics, but also affected by the presence and quality of Bonaire’s ecosystems. From this statistical analysis no strong significant impact of environmental variables onto the house prices has been detected and thus the hypothesis is rejected. This lack of evidence limits the possibility to calculate the amenity value. The cause of the poorly performing analysis is the limited data available on house sales on Bonaire.

Cultural value

The island of Bonaire has a precious though threatened nature and its culture is indistinguishable from nature. Yet, times are changing and so is the relationship between nature and society in Bonaire. Since the development of industrial times, less Bonairean practise agriculture, and less people are working in the nature. The objective of this study is to estimate the value of the cultural ecosystem services of the island of Bonaire. The scope of this sub-study is limited to four cultural values of ecosystems on Bonaire: (1) Recreational activities; (2) Subsistence and recreational fishing; (3) Kunukus; and (4) Cultural landscape. 

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.

We estimated the population sizes of the three species of columnar cacti that grow on the island of Curaçao using ground and aerial transects, and we examined the island’s carrying capacity for two species of nectar-feeding bats that depend on nectar from the flowers of these cacti. We calculated carrying capacity based on the daily availability of mature flowers between January and December 1993 and the field energy requirements of bats as estimated from an equation for eutherian mammals (low estimate) and one for passerine birds (high estimate) based on body mass. Additional energy requirements of pregnancy and lactation were taken into account. We estimated that 461,172 columnar cacti were present on Curaçao (38% Subpilocereus repandus, 51% Stenocereus griseus, and 11% Pilosocereus lanuginosus). May through September are the critical months when bats rely most heavily on cactus for food. July 1993 was a bottleneck with the smallest number of mature flowers per day. July and August were months of greatest energy demand because females were lactating. We estimate that the carrying capacity for Glossophaga longirostris in July, when the bat (Leptonycteris curasoae) population was 900, was near 1200, an estimate that fits the observed population size of nectar-feeding bats on the island. We suggest that the extensive removal of native vegetation occurring on Curaçao be strictly regulated because further destruction of the cacti will result in a decrease and potential loss of the already low populations of nectar-feeding bats.

Three species of columnar cacti (Stenocereus gri seus, Subpilocereus repandus, and Pilosocereus lan uginosus) are conspicuous elements of arid vegetation in northern Venezuela and several nearby islands induding Aruba, Bonaire, and Curacao. Stenocereus griseus and Subpilocereus repandus produce most of their flowers and fruits during the dry season (from January to September) on Curacao, Netherlands Antilles (Petit 1995). They provide food for several species of animals (especially bats and birds) during part of the dry season, when many other plant species are non-productive. The major pollinators of these self-incompatible cacti in Venezuela are the bats Leptonycteris curasoae and Glossophaga longirostris (Phyllostomidae) (Nassar 1991). An exhaustive census showed that bats of all species, induding L. curasoae and G. longirostris were threatened on Curagao (Petit 1995). Unidentified sphinx moths and two species of hummingbirds are other potential cactus pollinators on the island. In the Sonoran desert, all three groups are important pol linators of columnar cacti (T. Fleming, pers. comm.), and in most systems studied so far, bats are not exdusive pollinators of key plants. I determined the importance of moths, birds, and bats as pollinators of S. griseus and S. repandus pollination on Curacao because bats were expected to contribute significantly to cactus pollination, and evidence of their ecological importance was needed to prompt conservation action for bats and caves.

Two sympatric species of columnar cacti on Curaçao, Netherlands Antilles, share bat pollinators, overlap in flowering phenology, and are floral homologues. Leptonycteris curasoae curasoae and Glossophaga longirostris elongata (Chiroptera: Glossophaginae) visit flowers of Stenocereus (syn. Ritterocereus) griseus and Subpilocereus (syn. Cereus) repandus on the same nights; these visits may promote interference competition between cactus species. I studied the effect of heterospecific (mixed) pollen loads on fruit and seed set, fruit and seed size and mass, germinated seeds at 5 weeks, and seedling survival at 7 months in relation to hand pollination with intraspecific pollen and natural pollination. Hand pollination seemed to limit pollen loads available for pollination. Under these conditions, natural pollination tended to produce the most fruits and seeds, and the largest fruits (but lightest seeds); mixed pollination was the least effective treatment (fruit set was significantly greater for St. griseus in natural than mixed pollination; fruit volume was greater in natural than mixed pollination for S. repandus, and seed number and fruit mass were larger in intraspecific than in mixed pollination). Aspects of natural pollination, possibly repeated visits, compensated for the negative impact of interspecific pollen loads under pollen limitation, with positive impacts on the carrying capacity of cacti for frugivores. Seed mass from natural pollination was negatively correlated with seed number only for St. griseus. Germination success was not correlated with seed mass, but seedling survival at 7 months was for S. repandus. The two species do not seem to compete through pollen interference when pollinator visits are relatively frequent.

We examined the potential for exploitation competition by differential attractiveness in two sympatric species of columnar cacti on Curaçao, Netherlands Antilles. Stenocereus griseus and Subpiloccreus repandus have temporally overlapping flowering phenologies and share pollinators. We examined nectar volume, energy contents, and sugar ratios for the entire night and at two-hour intervals in both cactus species. Except for a burst in nectar volume and sugar concentration by Subpilocereus repandus during the first two hours of anthesis, nectar secretion patterns, energy contents, and sugar ratios (70% hexose) were similar for the two species. The standing crops of nectar in both species were kept very low by bat pollinators. We suggest that the potential for exploitation competition between Stenocereus griscus and Subpilocereus repandus is currently very low on Curapo.

Two species of columnar cacti, Subpilocereus repandus and Stenocereus griseus, are pollinated on Curacao by two species of glossophagine bats, Leptonycteris curasoae and Glossophaga longirostris (Phyllostomidae). The pollination effectiveness of the two bat species can influence the evolution of this mutualism as well as the immediate availability of resources to frugivores and omnivores. I examined the effectiveness of single-visits by L, curasoae and G. longirostris on fruit-set, seed number, and fruit size for each cactus species. Single visits of L. curasoae produced higher fruit-set and seed number in Subpilocereus repandus than did single visits of G, longirostris, but the differences were not statistically significant, possibly as a result of the small size of the L, curasoae sample. The reverse trends were observed for Stenocereus griseus, Pollination of Subpilocereus repandus by L, curasoae resulted in significantly longer fruits than did pollination by G. longirostris, During the peak of the flowering season, flowers received many visits per night. Fruit size (length, width, total mass, pulp mass) was positively correlated with the number of seeds per fruit. These results indicate that the species of bats visiting cactus flowers, as well as the number of visits to flowers, may affect pollination success, and consequently may affect the carrying capacity of the environment in terms of fruit resources for animals that feed on cactus fruits.
 
The effectiveness of two bat species as pollinators of two species of columnar cacti on Curacao.
Available from: https://www.researchgate.net/publication/239042041_The_effectiveness_of_...
[accessed Apr 16, 2015]