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SEYCHELLES

Status of Coleura seychellensis  in the Seychelles

Posted: 28 March 2008  By Laura Bambini         

The emballonurid Coleura seychellensis is endemic to the  Seychelles where it is the only microchiropteran. It is insectivorous and roosts in boulder caves.  Historically, C. seychellensis was reported to be abundant (Wright, 1868), but underwent dramatic declines in the 20th century, and is now Critically Endangered (IUCN Redlist, 1996-2007).  Surveys in 1972, 1974 and 1976 found these bats in low numbers on La Digue (Racey and Nicoll, 1984), and these were the last recorded sightings of C. seychellensis on that island.  On Praslin, a single individual was observed in 1996 (Mellanby et al., 1996).  Subsequent surveys found no C. seychellensis on Praslin or La Digue (Bambini et al., 2006).  Surveys carried out on Mahé  found C. seychellensis on the west coast of the island (Mellanby et al., 1996; Joubert, 2004; Bambini et al., 2006), and three roosts are known from boulder caves (Bambini et al., 2006).  A single roost is known from Silhouette Island (Joubert, 2004), and is reported to contain 32 bats (Gerlach and Taylor, 2006).  During three months of surveying in 2004 Bambini et al. (2006) confirmed the existence of 19 bats in three roosts on Mahé, but as with all such surveys this is likely to be an underestimate. 

Several reasons have been suggested as a cause for the decline in C. seychellensis,  including predation by the introduced barn owls Tyto alba (Racey and Nicoll, 1984), habitat degradation (Gerlach, 1997) and the use of pesticides (Bambini et al., 2006).  Monitoring of the populations was recommended by Rocamora (1997), and Rocamora and Joubert (2004), but very little was done.  The Aberdeen University  ‘Bats on the Brink’ expedition produced an Action Plan to encourage efforts to conserve the species (Bambini et al., 2005), and further work has been called for to study  habitat use and the specific conservation needs of C. seychellensis (Bambini et al., 2006).  A follow-up project  (‘Bringing Bats off the Brink’) was carried out  in 2006-2007, to investigate the causes of decline further, and to monitor changes in behaviour and population size of C. seychellensis.  The most significant observation was an increase in numbers of bats occupying the largest roost on Mahé to 27, bringing the overall number known on both occupied islands to about 70 (Senior et al., 2007). 

At present, legal protection for the bats and their roosts is still lacking despite the fact that the largest roost on Mahé is on government land.  

References 

Bambini, L., Blyth, A., Bradford, T., Burthe, S., Craig, L., Downs, N., Laing, S., Marshall-Ball, L. and McGowan, D. (2005) Bats on the Brink. Final Report, Unpublished. University of Aberdeen, Aberdeen, UK. 

Bambini, L., Blyth, A., Bradford, T., Bristol, R., Burthe, S., Craig, L., Downs, N., Laing, S., Marshall-Ball, L., McGowan, D., Vel, T. and Racey, P. (2006) Another Seychelles endemic close to extinction: the emballonurid bat Coleura seychellensis.

Oryx 40(3): 310-318. BP Conservation (2007) News from the field. BP ConservationProgramme Quarterly Newsletter 29: 3.  

Gerlach, J. (ed.) (1997) Seychelles Red Data Book 1997. The Nature Protection Trust of Seychelles, Mahé, Seychelles. 

Gerlach, J. and Taylor, M. (2006) Habitat use, roost characteristics and diet of the Seychelles sheath-tailed bat Coleura seychellensis. Acta Chiropterologica 8(1): 129-139. 

IUCN Redlist (2007) www.redlist.org Date accessed 20th March 2008. 

Joubert, F. (2004) A preliminary investigation into the general ecology, status and habitat use of the Seychelles sheath-tailed bat Coleura seychellensis (Emballonuridae). Phelsuma 12: 54-68.

Mellanby, R., Mee, A., Cresswell, W., Irwin, M., Jensen, M., McKean, M., Milne, L., Shepherd, E. and Bright, S. (1996) Glasgow University Expedition Report. Unpublished. Glasgow University, Glasgow, UK. 

Racey, P.A. and Nicoll, M.E. (1984) Mammals of the Seychelles. In Biogeography and Ecology of the Seychelles Islands (ed. D.R. Stoddart). pp. 193-208. Dr. W. Junk Publishers, The Hague, Netherlands.

Rocamora, G. (ed.) (1997) Rare and Threatened Species, Sites and Habitats Monitoring Programme in the Seychelles. Vol. 1. Monitoring Methodologies and Recommended Priority Actions. Unpublished report for the Seychelles Ministry of Environment/BirdLife International/European Union. Victoria, Seychelles. 

Rocamora, G. and Joubert, F. (2004) The Seychelles sheath-tailed bat Coleura seychellensis: monitoring methodologies and priority actions. Phelsuma 12: 48-53. 

Senior, S., Doak, N., Bristol, R. & Valmont, I. 2007.  Bringing Bats off the Brink: Conservation action for the critically endangered Seychelles Sheath-tailed Bat. Preliminary Report on a BP Follow-Up award. 

Wright, E.P. (1868) Notes on the bats of the Seychelles group of islands. Annals and Magazine of Natural History 2: 436-438.