Thailand: A lesson in sustainability

Piyaporn Wongruang, Bangkok Post, 6 Oct 13;

The long-term Chiew Larn reservoir study can serve as a template for other threatened forest ecosystems in the Kingdom, said Petch Manopawitr, conservation programme manager at WWF Thailand.

Mr Petch, whose office has been conducting a study on the redistribution of tigers in protected areas adjacent to the World Heritage Site of the Thungyai Naresuan and Huai Kha Khaeng wildlife sanctuaries, said forest fragmentation caused by development projects - including the building of dams - has been studied by ecologists worldwide.

But because the study at Chiew Larn has been published in Science it has garnered much-needed publicity.

The study has been designed to cover a long enough time period to demonstrate changes in the ecosystem both systematically and scientifically.

Led by Luke Gibson of the National University of Singapore, a group of scientists paid several visits to the fragmented forest islands of Chiew Larn shortly after the dam was built more than 20 years ago. On each visit, they collected data on species' survival in the area. The scientists found that none of the native species left on the islands - which in total cover almost 100 hectares - were sustainable. Worse, an invasive species - the Malayan field rat - became prevalent.

The study shows a correlation between forest fragmentation and species extinction, but what surprised Mr Petch most was the alarming rate at which species became extinct.

Because the study has been conducted here, much weight has been given to the implications for other forested areas in the country, said Mr Petch.

"Locally, we don't have much research on the long-term impact of forest fragmentation caused by development projects, but this study has proved to us all that ecological devastation can happen when a forest is fragmented," said Mr Petch.

"The implications of this study are very clear. If we want to preserve a good ecosystem, we need to protect large or connected forest areas."

Mr Petch added such results could easily occur elsewhere. At Mae Wong National Park, where the Mae Wong dam is planned, Mr Petch hypothesised that the consequences would be similar to those at Chiew Larn. Both are mountainous and prone to forest fragmentation by building dams, he said.

The study has also confirmed that the disappearance of native species means that for ecologists such as Mr Petch, efforts to rescue and rehabilitate such species after the dam is built would be futile.

Prevention, which allows for rehabilitation - not mitigation - is the best measure to preserve the ecosystem, he concluded.

Mr Petch urged the government to take heed of the study's findings. He said the government's claim that only 1% of the forest in Mae Wong would be damaged by the building of the dam is unacceptable.

The dam will eventually affect its ability to sustain species, he said.

He added that the government should scrap all development projects in pristine forests. Thailand, he said, has been heavily devastated by deforestation and the country cannot afford to lose more.

Mr Petch said these areas should be connected by eco-corridors, but the implementation and development of these must allow for the survival of wild species.

"Future conservation work is really about how we can preserve the protected areas," said Mr Petch.