Seychelle Islands Sheath-tailed Bat Conservation Update 2010

Dec 14, 2010
Dawn M. Smith

Mahe Island has Seychelles Sheath–tailed Bats - Hansueli Krapf

Endangered mammals on the Seychelles benefit from increased knowledge of diet and habitat. Proposed national park includes key foraging and roosting sites.

Some populations of the critically endangered Seychelles sheath–tailed bat (Coleura seychellensis) have begun to recover, thanks to the efforts of the Nature Protection Trust of Seychelles (NPTS). The results of more than 10 years of research have allowed the NPTS to improve habitat and make science–based recommendations for long–term sheath–tailed bat conservation on the Seychelles.

Invasive Weeds Affect Seychelles Sheath–tailed Bats

Habitat loss and degradation played an important role in the decline of the Seychelles sheath–tailed bat. Invasive weeds such as kudzu vine blocked the entrance to roosts, forcing the endangered mammals to abandon many traditional roosting sites.

Kudzu vine and other invasive weeds create a secondary problem for these insectivorous bats as well. These alien plants don’t provide adequate forage for beetles and moths, which make up an important part of the bat’s diet. One non–native species, Cocos nucifera, supports numerous ants which, unfortunately, suppress other insect populations.

Other Threats to Bat Conservation on the Seychelles

Several important bat roosts and foraging areas are close to human settlements. Insect foggers used in those areas against mosquitoes also reduce the populations of beetles and moths, which are primary food sources for the sheath–tailed bat. Smoke from nearby fires has also been shown to cause significant disturbance in roosts during daylight hours when the endangered mammals are resting.

Trash disposal in the areas near primary bat foraging and roosting sites results in the increased presence of feral cats and rats, which pose a threat to the Seychelles bats. These trash dumps are sometimes burned, adding to the smoke disturbance problem.

Bat Conservation Makes Progress on the Seychelle Islands

Habitat restoration at one site, La Passe on Silhouette Island, resulted in increased beetle populations which in turn increased bat foraging activities in the area. This was followed by increased reproduction in the local sheath–tailed bat population. Further efforts to reduce disturbance and continue habitat restoration were needed as development in the area created secondary problems but the La Passe roost now supports a stable population of Seychelles sheath–tailed bats.

Similar habitat restoration and management activities are being initiated at a second site, Grand Barbe, also on Silhouette Island, where a few bats have been seen. In the longer term, the proposed national park, which would encompass a large part of Silhouette Island is likely to include much of the critical Seychelles sheath–tailed bat habitats on this island.

The Nature Protection Trust of Seychelles is working with the Seychelles Ministry of the Environment to extend their habitat restoration and protection activities to several sites on Mahe Island, where there are three known bat roosts, the largest of which is adjacent to a site approved for hotel development.

The successful recovery of at least one Seychelles sheath–tailed bat population through habitat restoration and management is a positive sign for the long term survival of this endangered mammal.

Continued cooperation between the Nature Protection Trust of Seychelles and local tourism development agencies to identify and protect known and potential roosting and foraging areas may save this Seychelle Islands endemic species from extinction. On Silhouette Island, this cooperation is already taking place. The Labriz Hotel has provided ongoing labor for habitat restoration and management to aid their local Seychelles sheath–tailed bat population since 2008.