There are highly biodiverse karsts scattered across Southeast Asia, from Vietnam to Borneo, like desert islands surrounded by oceans of tropical rain forest. The destruction of karsts at the hands of cement companies, developers and tourists is a problem throughout the region.

But it is particularly acute here, where government regulation is lax and the state of local scientific knowledge fledgling.

“They are threatened, as they are elsewhere, but the difference is that there is almost nothing known about the biodiversity of the hills” in Cambodia, said Tony Whitten, the international regional director for Fauna and Flora International’s Asia-Pacific division, who coedited a book on the subject — “Biodiversity and Cultural Property in the Management of Limestone Resources: Lessons from East Asia.”

Cambodia has almost no botanists and the study of plants in the country came to a standstill from 1970 to 1992 during an extended period of war and unrest punctuated by the trauma of the Khmer Rouge takeover from 1975 to 1979.

The country’s main herbarium is a single room at the Royal University of Phnom Penh. It houses about 12,000 specimens, many of which have not been inventoried and are simply piling up on shelves. They are meant to be kept cool and dry by two air-conditioners, but one air-conditioner is broken and there is no money to fix it.

“You talk about a herbarium in another country and it should be very big, but this is just one room,” said Ith Saveng, who runs the university’s Center for Biodiversity Conservation. “We hope to expand to another room within the next two years.”

Rare plants found in karsts have to be shipped to Vietnam so better-trained scientists can do the precise work of matching species to species.