Native mammals vanish from forest islands

One day they’re there, the next they’re not. Just 25 years after a Thailand forest was splintered into fragments, nearly all the small mammal species in the area have disappeared.

The creation of Thailand’s Chiew Larn Reservoir in the 1980s transformed a 165-square-kilometer patch of forest into more than 100 scattered islands. A research team wanted to find out how quickly species would go extinct in the remaining slivers of habitat. This knowledge is crucial for helping managers determine how much time they have to restore forest fragments before biodiversity plunges.

The team monitored small mammals on 12 to 16 islands, checking in five to seven years and 25 to 26 years after the reservoir was formed. By the second round of surveys, “native small mammals had virtually disappeared from all 16 islands,” the authors write in Science. Instead, the invasive Malayan field rat had taken over the forest fragments.

“It was like ecological Armageddon,” said co-author Luke Gibson of the National University of Singapore in a press release. “Nobody imagined we’d see such catastrophic local extinctions.”

The study suggests that the combination of forest destruction and invasive species could wipe out native animals even more quickly than expected. Conserving large areas of forest is vital to stave off such ecological disasters, the authors say. Roberta Kwok | 26 September 2013

Source: Gibson, L. et al. 2013. Near-complete extinction of native small mammal fauna 25 years after forest fragmentation. Science doi: 10.1126/science.1240495.

Image © tanoochai | Shutterstock