|Scientific Name:||Emballonura semicaudata|
|Species Authority:||(Peale, 1848)|
|Red List Category & Criteria:||Endangered B1ab(iii,iv,v) ver 3.1|
|Assessor(s):||Bonaccorso, F. & Allison, A.|
|Reviewer(s):||Lamoreux, J. (Global Mammal Assessment Team), Racey, P.A., Medellín, R. & Hutson, A.M. (Chiroptera Red List Authority)|
Listed as Endangered because its extent of occurrence is less than 5,000 km2, its distribution is severely fragmented, and there is continuing decline in the quality of its habitat, number of locations, and the number of mature individuals.
|Previously published Red List assessments:|
|Range Description:||The Pacific Sheath-tailed bat contains four subspecies:|
Emballonura semicaudata rotensis is found on the Marianas, and was historically on Guam, Rota, Aguiguan, Tinian, Saipan. Today it is only present on Aguiguan Island.
E. s. semicaudata was historically found in Samoa, American Samoa, Fiji, Palau, and Tonga. In Samoa, it was found on Savai'i and Upolu, where it was common; in American Samoa, it was found on Manua and Tutuila. This species has now disappeared from Samoa and American Samoa (Tarburton 2002). In Tonga, it was found on Eua and Niuafoou, and was last collected in 1989. In Fiji, it was found on Taveuni, Ovalau, Viti, Levu Lakiba, the Yasawas, and Rotuma (it is common on the last). The species is also known historically from Vanuatu (Koopman 1997).
E. s. sulcata occurs on the islands of Chuuk and Pohnpei in the Caroline Islands, and is doing well on at least Pohnpei. It is not found in the Marshall Islands (there was an erroneous record of presence from there).
E. s. palauensis is found on Palau, including Koror, Peleliu, Babelthuap, and Anguar, where it is common. It ranges from sea level up to 210 m asl (Wiles et al. 1997).
Native:American Samoa (American Samoa); Fiji; Micronesia, Federated States of ; Northern Mariana Islands; Palau; Samoa; Tonga
Regionally extinct:Guam; Vanuatu
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species was previously a common species over much of its range. E. s. rotensis was last observed on Guam in 1972, and was thought to have become extinct in the Northern Mariana Islands after 1932 until recent confirmation of a population on Aguiguan Island in 1984. It is estimated that 150 to 300 animals remain there with no immediate threats (Hutson et al. 2001). Populations in Fiji have significantly declined and may be extinct on Viti Levu (Flannery 1995). The subspecies E. s. sulcata and E. s. palauensis are thought to be stable, but there are limited data to support this (Hutson et al. 2001).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This is a small (five gram) bat with high site fidelity to caves. E. semicaudata is usually considered a cave-dependent species (it prefers cave entrances), but it also has been found roosting beneath overhanging cliffs. The species has been recorded flying in daylight under forest, but normally emerges at dusk. Details of its diet are not known (Hutson et al. 2001). E. s. rotensis is found primarily in forested habitats on Aguiguan (Esselsytn et al. 2004).|
Reasons for the declines and disappearances of the Pacific Sheath-tailed Bat are unclear. There have been continual declines since 1945. Threats include the disturbance of roosting sites, pesticide contamination, the loss of native forests to agriculture and grazing, invasive species, and stochastic events.
Monitor lizards, cockroaches, and rats may limit the selection of roosting sites on Aguiguan. During WWII caves in the Marianas were bombed (some caves were also sealed off during this time); since then, there has been limited disturbance of roosting sites (limestone caves), resulting from cave visitation and guano mining. Pesticide use is another potential threat. In Fiji, the disturbance to caves and burning of forest near roosts are possible causes of decline. In American Samoa and Samoa the effects of cyclones may have an effect, although the populations here will have experienced such perturbations in the past. The conversion of forest to agriculture must have had an effect, while other factors such as introduced cats and rats, pesticide use, and disturbance to caves are likely to have had a minor influence (Hutson et al. 2001).
|Conservation Actions:||Although there have been no conservation actions to protect this species to date, it is fully protected by legislation in Samoa, Guam, and in the Northern Marianas Islands. Suitable conservation actions for this species include the protection of known roosting caves, and the identification of additional important roosting sites. Surveys are needed on population status and trends, as well as ecology, and threats (e.g., pesticide levels). A proposed survey of fossil remains on many of the southern islands of its historical range could yield potential translocation sites.|
|Citation:||Bonaccorso, F. & Allison, A. 2008. Emballonura semicaudata. The IUCN Red List of Threatened Species 2008: e.T7669A12841889.Downloaded on 23 January 2017.|
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