Thirteen percent of more than 2,500 freshwater species of fish, crabs and plants profiled across the region are under threat of extinction, a report released on Wednesday says.

According to an International Union for Conservation of Nature study of freshwater biodiversity in the “Indo-Burma” region, which includes Cambodia, that figure could soar as hydro-electric dams are built.

“The development of hydropower dams throughout the Indo-Burma region is among the most crucial threats to aquatic biodiversity,” the Status and Distribution of Freshwater Biodiversity in Indo-Burma says.

“These projects are changing fundamental hydrological and water quality conditions . . . of many rivers, completely altering aquatic habitats with little understanding of the impacts. . . on fish biodiversity.”

Environmental groups are concerned that projects such as the Xayaburi dam, a 1,285-hectare hydro dam proposed for the Mekong in northern Laos, could affect the livelihoods of Cambodians who depend on the river.

William Darwall, a spokesman for the IUCN Global Species Programs, said hydro dam construction could increase the percentage of threatened fish species from 19 to 28 per cent within a decade.

“There is still time for this . . . report to help large-scale developments . . . proceed in a sustainable way with reduced impacts,” Darwall said.

To contact the reporter on this story: Shane Worrell at [email protected]