Indonesia’s tropical forests are the world’s third-largest and the most ecologically important after those of the Amazon and Congo basins. Their biodiversity is astonishing, with 515 mammal species — the most of any nation — and 1,539 bird species. Alas, Indonesia has another more dubious distinction: It also ranks fourth on the list of countries with the most species in imminent danger of extinction.

Between 1990 and 2015, Indonesia lost nearly a quarter of its forests, chiefly due to deliberate fires intended to clear land for palm oil and timber plantations. (Rare tropical hardwoods can fetch as much as $1,375 per cubic yard.) It is estimated that 80 percent of this activity was illegal, but political corruption prevents the existing laws from being enforced. (Rampant illegal burning has caused major diplomatic rifts with neighboring countries, notably Singapore and Malaysia, whose cities have been shrouded in dense smoke, causing serious health consequences for their citizens.) Aside from the irreversible loss of biodiversity, the destruction of Indonesia’s forests also has alarming implications for the global climate.

Conservationists generally agree that the preservation of glamorous “flagship” species, which readily attract public interest and sympathy, is an effective way to protect an entire ecosystem. Here are Indonesia’s Big Five.