The Australasian Bat Society predicts that the Christmas Island Pipistrelle bat has less than six months left until extinction, unless measures are taken immediately to set-up a captive breeding population.
Found only on Christmas Island in the Indian Ocean—an Australian territory—the Christmas Island Pipistrelle bat was first labelled as Critically Endangered by the Environment Protection and Biodiversity Conservation (EPBC) Act 1999 in 2006. Its continuing decline is a mystery. In the 1980s, surveys showed the bats to be common on the island, but by the mid-1990s a widespread decline was evident. The population then dropped precipitously: a study in 2006 showed a 99 percent decline of the Christmas Island Pipistrelle since 1994.
A letter written by Dr. Lindy Lumsden states that ”a reassessment of the number of individuals remaining in January 2009 suggests there could be as few as 20 individuals left. The only known communal roost contains only four individuals. Three years ago there were 54 individuals in this colony and there were several other known, similar-sized colonies. The long-term monitoring data and the recent reassessment suggest that, if the current rate of decline continues, this species is likely to be extinct within the next 6 months!”
While there are theories regarding the cause of its disappearance, there is no smoking gun. Habitat loss is not a factor, since 75 percent of the island remains covered by primary or secondary forest. Its food source—flying insects—also appear abundant. While disease could be a cause, to date there is no evidence of the bats suffering from an illness.
The most likely cause is predation by introduced species such as the common wolf snake, feral cats, giant centipede, and black rats. Lumsden believes a recent outbreak of yellow crazy ants may have also exacerbated the decline.
Considering that so few individuals remain, Lumsden has called for an emergency captive breeding program to save the species. In order to do so, scientists would need to be allowed to capture the remaining bats to establish the breeding program. Even now, Lumsden worries there may not be enough bats left on the island for such a program: ”there is a risk there will be so few animals left that it will not be possible to catch them.”
The Christmas Island Pipistrelle is one of Australia’s smallest bats, weighing in at 3 grams (0.1 ounce).
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