Flood mitigation works threatening Malaysian firefly colonies

Tan Cheng Li, The Star 6 Aug 10;

PETALING JAYA: Firefly colonies in Negri Sembilan and Malacca are in danger of being wiped out following river engineering works to alleviate flooding in low-lying areas.

A three-year research showed that clearing of riverine vegetation to widen and straighten Sungai Rembau and Sungai Linggi had adversely affected populations of the insect, which congregate on mangrove trees and synchronously light up in a dazzling display.

Of the 122 colonies of fireflies recorded in 2008 in the Rembau-Linggi estuary, only 64 were observed by June 2010, according to surveys by Wan Faridah Akmal Wan Jusoh, who did her masters programme on firefly ecology at Universiti Pertanian Malaysia.

Presenting her findings at the International Firefly Symposium here, she said river modification for flood mitigation had drastically changed the mangrove ecosystem by destroying trees on which fireflies gathered to mate.

“The construction of bunds along rivers have also disturbed the ecology of the river, soil and vegetation,” she said.

Her research showed the Rembau-Linggi estuary to have abundant colonies of fireflies, with four of the six rivers there – Rembau, Linggi, Ramuan Cina Kecil and Ramuan Cina Besar – hosting the insect, but populations had diminished following the destruction of mangroves.

Since 2007, Wan Faridah has surveyed a total of 13km of the rivers. Unfortunately, at least 64 mangrove trees where she had observed congregating fireflies were felled during river engineering work by the Drainage and Irrigation Department.

She said tourism activities in the area, which included fishing as well as firefly and crocodile sighting, had declined due to changes in the habitat.