Some firefly colonies are disappearing even before they are identified, alongside destruction of their habitats by pollution and riverine development.
THE sight of several thousand fireflies twinkling along a riverbank is a magical experience, one that draws in tourists, both local and foreign. Malaysia is one of the few South-East Asian countries with fireflies that congregate on “display trees” along both sides of mangrove-lined rivers. The insects can even be found congregating up to 100m inland from the riverbank where they breed.
As Malaysia is at the centre of the firefly region that stretches from India to Papua New Guinea, we are fortunate to have a relatively high diversity of the insect. Of the over 20 species of fireflies, Malaysia hosts seven.
Of these, the most familiar would be the Pteroptyx tener, also known as the congregating or synchronous firefly. These fireflies typically congregate in groups along riverbanks and synchronise their flashes, thereby creating the light display that so many people gather to witness.
Places like Kuala Selangor have made firefly-watching a lucrative tourist attraction since the 1980s. What most people don’t know is that many other congregating firefly habitats in Malaysia are slowly being wiped out, both by ignorance and irresponsible development.
The preliminary findings of a six-month study of firefly habitats in peninsular Malaysia by the Malaysian Nature Society (funded by the Mohamed Bin Zayed Species Conservation Fund) paints a rather alarming picture.
While there are still many intact mangrove-lined rivers in Pahang, Terengganu, Perak and Johor that support congregating firefly populations, the localities in Selangor, Kedah, Kelantan, Perlis and Penang have been reduced to just one or two. In the states of Negeri Sembilan and Malacca, most of the fireflies’ habitats have been eliminated, due to the clearing and bunding of rivers.
According to MNS senior conservation officer Sonny Wong, the firefly habitats are primarily threatened by riverbank clearing, strong light sources along the rivers, and pollution of the river itself.
“Riverbank vegetation is often cleared and bunds erected to establish shrimp farms and oil palm plantations,” Wong explains. “Unregulated dumping of chemicals used in these activities often end up in the rivers. Besides that, light pollution along the rivers in the form of spotlights from aquaculture farms, fish farms, sand mining dredges, ports and factories creates additional negative impact, as fireflies are driven away by these strong lights. All these activities threaten the congregating fireflies’ life cycle and survival.”
The riverbanks of Sungai Sitiawan in Perak, which used to be the habitat of fireflies, have been disturbed by the presence of shrimp farms.
Even the healthy rivers that support congregating fireflies in the states mentioned above, however, are not completely safe – they face potential harm from flood mitigation measures that are being implemented by the Department of Irrigation and Drainage (DID). This was seen after the floods at Kota Tinggi, Johor, in 2007, when the river was deepened to prevent future flooding.
While well-intended, such measures have already affected several congregating firefly rivers such as Sungai Linggi-Rembau, Sungai Sedili Kecil, Sungai Johor, and parts of Sungai Perak.
“The DID does have guidelines on how to clear rivers. The problem is that the jobs are given to contractors, who perhaps don’t follow these guidelines,” says Wong.
He further explains how the Linggi-Rembau river is one of the most affected ones, with its firefly watching area almost completely destroyed.
The problem is compounded by the fact that very little is known about the life cycle of the firefly itself. It spends the first three months of its life in the larvae stage, and less than a week as an adult, during which time, it will try to mate. For the synchronous fireflies, the mating occurs on the riverbank of mangrove-lined rivers. The mating, however, is a competitive process as the ratio of females is lower.
“The problem is that hardly anyone studies fireflies in this region,” says Wong, who has been surveying firefly populations in Malaysia for more than 10 years. “No one knows the complete life cycle; the Forest Research Institute Malaysia has studied it in the lab, but the details are still disjointed. Without this information, it isn’t easy to restore or restore the populations that have been lost.”
As always, it comes down to a matter of finances, and currently, more funding is needed to carry out these studies.
Wong hopes that the survey he is working on will initiate positive response from the Government.
“The idea behind the study is to find out how many rivers (in Malaysia) have congregating firefly populations. We estimate that there are about 70 sites, of which we have surveyed 20, and plan to do five more. Then, we will compile the information in a directory as future reference for research, education, awareness, and most importantly, for Government action,” says Wong.
MNS plans to approach DID and other relevant Government agencies with the survey’s results, to encourage them to re-examine their methods in executing flood mitigation projects and protect the remaining rivers that support congregating fireflies.
Wong plans to have a preliminary meeting with the various Government agencies later this month and nurses hopes of long-term solutions as well. Among these is the passing of a river reserve act that will prevent irresponsible clearing and polluting of rivers and riverbanks.
“The Government also needs to think again about how to mitigate floods, instead of simply clearing and bunding rivers. The Economic Planning Unit plays an important part too, as it should be convinced that floodplains like these areas should not be developed.”
He also hopes to develop more of the congregating firefly rivers into eco-tourism sites, specifically by getting the locals in the area involved.
“While there are currently about 14 firefly-watching sites in Malaysia (other than Kuala Selangor), the operators there are not locals, and they aren’t regulars. Therefore, they don’t practice ethical firefly-watching,” says Wong. For example, he explains how many of these operators shine bright lights into the riverbank trees to force the fireflies to come out, which then disrupts the insects’ mating and behaviour patterns.
“From a conservation point of view, it is better to use locals. We (MNS) will teach them the ethics of firefly-watching, and it will provide them with a means of livelihood. They can also feel a sense of ownership over the area, and be the “eyes” of the site, so to speak,” says Wong.
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