Scientific research can pay real dividends for bat conservation by filling the gaps in our knowledge of these incredible animals. And when fascinating research is combined with training and using volunteers, it can often build a dedicated cadre of conservationists who remain committed to bats long after the fieldwork is complete. That’s what we found in our study of Curaçaoan long-nosed bats on the Caribbean island of Aruba.
Aruba, along with Bonaire and Curaçao, is part of the ABC Islands off the northwest coast of Venezuela. Strung along the Peri-Caribbean Arid Belt, the islands are home to a unique diversity of plants and animals adapted to this desert-like ecoregion of the Neotropics. But many of these species are at risk, as their natural habitats are rapidly consumed by urban and recreational developments. Protecting the bat species of the ABC Islands is essential for preserving this biodiversity.
Bat-plant interactions, from which both the bats and the plants benefit, are vital for sustaining life in the arid and semiarid ecosystems of the Caribbean. Two nectar-feeding bats – the Curaçaoan long-nosed bat (Leptonycteris curasoae) and Miller’s long-tongued bat (Glossophaga longirostris) – are primary pollinators and/or seed dispersers for several species of columnar cacti and agaves. And these plants provide food and water to a broad range of birds, rodents, lizards, butterflies, bees, wasps, hawk moths and many other creatures, especially during the long droughts that frequently occur. This is especially critical in small, island ecosystems like the ABC Islands, where populations of several plant and bat species are declining.
Both nectar bats are native to all three islands and the mainland of Venezuela. Miller’s long-tongued bats roost in caves, tree hollows, rock holes and house roofs, but Curaçaoan long-nosed bats are less versatile, relying mainly on caves as refuges and maternity roosts with colonies numbering in the hundreds to thousands. They are especially susceptible to human disturbance and the species is listed as Vulnerable by the IUCN.
Ongoing research on Curaçao and Bonaire has identified several important caves used by L. curasoae throughout the year. Based on these studies, management and conservation actions have been proposed to help protect these roosts. Until now, no similar studies had been conducted on Aruba Island, a favorite destination for tourists.
With support from BCI’s Global Grassroots Conservation Fund and other sources, we launched our one-year project on Aruba in March 2012 to identify the main roosts used by the Curaçaoan long-nosed bat in Aruba, determine how and when the roosts were used and assess their conservation status.
Our first step was to assemble a team of volunteers to survey and monitor the caves. We conducted the first Bats and Caves Monitoring Workshop of Aruba to educate our nine participants about the ecological and economic importance of bats and train them in the capture, identification and release of bats and in the use of ultrasonic bat detectors.
The workshop coincided with our initial monitoring session, so participants attended lectures and demonstrations during the day, then received hands-on training each evening in the capture and safe removal of bats from mist nets and in species identification.
These trained volunteers of the “Aruba Team” conducted bat-monitoring sessions. By the third session, the team was totally independent and handled the monitoring and data collection entirely on its own. In fact, the Aruba Team added and trained two additional volunteers as the year progressed.
There is now a committed community of knowledgeable bat conservationists on Aruba, people who remain active in bat research projects and in conservation initiatives of their own. Officially recognized as the Bat Conservation Program for Aruba, they have joined RELCOM (the Latin American Network for the Conservation of Bats) as part of the Bat Conservation Program for Aruba, Bonaire and Curaçao (PCMABC).
The volunteer monitors visited seven major caves and mines on Aruba to search for evidence of bats, which we found at four sites: Quadirikiri Cave and Miralamar Mine inside the Arikok National Park, and Tunnel of Love Cave and Wela Mine outside the park’s partial protection.
We used mist nets to monitor these four roosts every two months during the project. Each monitoring team included two to four people handling the netting and two or three others who examined the bats. We also created a guide to identify the bats of Aruba.
We captured a total of 1,075 L. curasoae at the four sites. Tunnel of Love, protected by a fence since 2008 and located about 1,600 feet (500 meters) from a wind-energy facility, seems to host the largest colony of the species, followed by Miralamar Mine. Comparatively fewer long-nosed bats were captured at Wela Mine, which may serve as an emergent or last-option roost. Only one of the bats was captured at Quadirikiri Cave.
Our results suggest that Tunnel of Love could be the island’s main roost for mating, while Wela Mine and Miralamar Mine are probably used as maternity roosts.
After the project ended in March 2013, the monitoring program continued on its own, thanks to the commitment of members of the Aruba Team, especially Coordinator Indra Zaandam and technical assistant Linda Smith. They have marked 1,606 Curaçaoan long-nosed bats with tiny identification tags and have recaptured 64 of them. Of these animals, 89 percent were recaptured in caves other than those where they were originally tagged. This suggests the bats move frequently among the caves, which are a few miles apart. In other words, Curaçaoan long-nosed bats on Aruba depend on a system of roosts rather than a single cave, and their conservation requires the protection of all their roosts.
In summary, our results strongly support the need for a system of protected caves on Aruba in the form of a Bat Reserve, which should include at least the four caves and mines analyzed in this study and any other bat caves that could exist on the island.
Our project generated considerable interest about the bats of Aruba in the regional media and on the Internet. At least 23 newspaper articles were published in English, Dutch and the Papiamento dialect, along with five radio interviews and three on TV. Members of the Aruba Team explained the importance of bats and the need for their conservation, as well as the monitoring process. The publicity definitely caught the public’s attention and generated many requests to the Arikok National Park for more information. It also led several people to volunteer their assistance to the Aruba Team.
A number of bat houses have appeared on the island, and the Aruba Team has launched a bat-education campaign for schoolchildren and the general public.
We plan to continue our monitoring efforts on Aruba, as well as Curaçao and Bonaire. We also hope to continue the tag-and-recapture effort with the Curaçaoan long-nosed bat to confirm whether bats of this species are permanent residents of the island or move periodically to other islands or the mainland in search of resources.
Although many challenges remain, the future looks a lot brighter for these island bats with Team Aruba on the job as their vigorous champion.
JAFET M. NASSAR is Associate Researcher at Centro de Ecología, Instituto Venezolano de Investigaciones Cientificas in Venezuela. FERNANDO SIMAL is Chief of the Natural Resources Unit of STINAPA Bonaire (the National Parks Foundation of Bonaire).
This study also received funding from STINAPA-Bonaire (the National Parks Foundation), Arikok National Park and the Dutch Caribbean Nature Alliance.