Deep in the eastern Himalayas, where two continental plates and four countries converge, a treasure trove of new species has kept scientists on the lookout for the past decade. A recent report, assembled by the World Wildlife Fund International (WWF) based in Washington, D.C., gathered the fruits of these labors—completed by various organizations—and lists the 353 new plant and animal species that years of rugged research have now brought to the wider world's attention.

From the soaring, 8,000-meter mountain peaks of Tibet down through deep gorges and into lowlands of dense, sea-level rainforests in Assam, the eastern Himalayas offer a wealth of species in a range of distinct biomes.

The extreme terrain has kept many of these species hidden from scientific observation for centuries. "Forests are so thick you have to rely on the knowledge of local hunters or people," says Jon Miceler, director of the WWF's Eastern Himalayas Program. "A huge amount [of research] is done through asking people what's out there."

The remote area has yielded some remarkable discoveries. The 2005 description of a new primate, the Arunachal macaque, stunned researchers, who hadn't catalogued a new primate in more than a century.

Slide Show: New Species Discovered in the Himalayas

Miceler and others were also amazed by the report of the tiny leaf deer, which is just a fraction of the size of a North American white-tailed deer. "It's almost something out of science fiction," Miceler says. "You can hold this thing with two hands." That is, if you can find it. The rare photo was only captured after multiple treks into the dense forest. To locate the small animal, researchers got help from locals, some of whom even had skulls of the deer as trophies.

George Amato, who helped describe the leaf deer—and is now director of the Sackler Institute of Comparative Genomics at the American Museum of Natural History in New York City—notes that the late 1990s saw a rush of interest to discover and name new species in remote regions like this. Although many announcements were based on unsubstantiated observations, genetic analysis has helped researchers sort the novel from the nonsensical.

"By using these methods, we're discovering a lot of cryptic diversity," he says, explaining that many animals that appear similar actually turn out to be unique species. (And, conversely, even those animals that look vastly different can be male and female versions of the same species.) The genetic analysis, especially as the time and funds required for processing declined, has become an important intermediate step for new species identification. "Even with the leaf deer we were able to generate a lot of DNA data showing it was distinct from the only known deer in the region…. Subsequent examination of morphology showed it was different," Amato says.

The latest DNA testing can even gather readings from animal remains, feathers or even a fecal sample, Amato says.

But even as these species are at last being catalogued, their habitats are being threatened by deforestation and mineral mining. "The eastern Himalayas squeeze between the two rising Asian superpowers, China and India—and these countries need resources," he says.

Climate change, too, is already being felt in the heart of the Himalayas. "As it gets warmer, ecosystems literally begin to move up to adjust to these new temperatures," he says. And animals that already live at the top altitudes, such as snow leopards, don't have any more habitat to move into. Rapid glacial melting has also caused devastating floods, Miceler notes, which have decimated human settlements along with important animal habitats.

But living in an area of political dispute seems to have helped to protect some of these animals. "It's a no-man's-land where not many people are allowed to go," Miceler says. He likens the area to the demilitarized zone, a stretch of land between North and South Korea, which, he says, "is incredibly intact." Such a location has "actually preserved them," he says. "In some senses, the restrictions on these areas have kept away forms of development that would have sped up the degradation, such as logging."

Such a dubious status, however, does have its detractions, Amato says. It protects the area from easy development, but "on the other hand, you can't have a secure protected area," he notes. And the status quo of political limbo becomes crucial to retaining the current levels of biodiversity. Now, for instance, as relations between northern Myanmar (Burma) and China have improved, more areas for trade and resource exploitation have opened up, he explains. "All in all, I would take a secure network of protected areas over a politically unstable place. That's a better hope for long-term conservation of species," he says.