Emma Stokes doesn’t do things the easy way. Her conservation successes have come in areas riddled with logging concessions, swamp forests devoid of trails, and on spreadsheets that measure wildlife results against tough business models.

Her astonishing discovery of 125,000 lowland gorillas in an partly unexplored region of Congo transformed assumptions about the critically endangered apes. New challenges find her working on behalf of another species on the verge of vanishing—the Asian tiger. “In many cases,” Stokes believes, “conservation isn’t rocket science. It’s simply a matter of knuckling down, doing what we know how to do, and staying focused.”

Her work with the Wildlife Conservation Society (WCS) began in the Republic of Congo, where commercial logging activity was rapidly encroaching on remote wilderness areas, some protected, some not. “WCS pioneered a conservation project working with a private logging company, local communities, and the government,” she recalls. “By concentrating on goals we all shared, we were able to manage and conserve wildlife populations, even ones within areas being logged.”

Years of planning large-scale surveys to measure conservation effectiveness ultimately brought her to the edge of a forest so impenetrable and inhospitable, it remained virtually unexplored by humans. To Stokes, it was irresistible.

“We knew this area was important for gorillas, but we never expected to find them in such high numbers,” she says.

The area included large tracts of swamp forest that is permanently flooded, thus undisturbed by logging companies. Stokes’s team slogged their way between tree limbs, using pruning shears to open passages just wide enough to squeeze through, often sleeping on hammocks hung from exposed tree roots.

“We wanted to minimize our impact at all costs,” she explains. “To count gorilla nests or dung you must maintain a straight line trajectory, so surveying was especially challenging. If we were lucky we’d cover one or two kilometers a day.”

The huge, unknown gorilla population they discovered astounded the conservation world, and catalyzed Congolese government action toward designating part of the region as a new protected area.

“Although 125,000 sounds like a lot of gorillas,” she cautions, “that population can dwindle very quickly if it’s hit by an Ebola outbreak.” The last known outbreak of the deadly virus occurred on land just adjacent to the survey area. “We may know how to address threats from bush meat hunters and loggers, but this new danger from disease will be much harder to predict and control.”

Today Stokes brings similar monitoring techniques and threat-management approaches to a major international effort to save Asian tigers. WCS and Panthera, a big cats charity, partner to run the Tigers Forever project.

“Tiger numbers have plummeted," Stokes notes. "In 2010, there are only about 3,200 left in the world. Habitat loss, hunting for skins and medicinal products, and poaching of tiger prey have taken the greatest toll.”

“Our goal is to increase tiger populations by 50 percent in nine key sites across Asia over a ten-year period,” she explains. The sites, spanning countries from Russia to India, were pinpointed for their potential to successfully foster tiger recovery. “Focusing on securing these source breeding populations first will be essential to broader repopulation.”

The program’s classic business model is unusual for conservation. “We’ve set clear goals, announced them in advance, and are being held accountable,” Stokes says. “Getting reliable numbers on tigers, poaching, and other threats isn’t an easy or straightforward task but it’s extremely important. It tells us what’s working, what’s not, and where to invest efforts. For tigers it’s crucial, because time is running out and resources are always thin.”

Stokes is charged with coordinating across all sites, developing tools to track how tiger and prey populations increase, how poaching is effectively reduced, and how well habitat integrity is maintained. Data are gleaned from field cameras triggered by motion sensors or infrared beams. Because each tiger bears a unique stripe pattern, photographs allow conservationists to estimate population numbers. Stokes also helps sites target interventions, including better patrolling and improved law enforcement.

Although surrounded by disappearing species for more than a decade, Stokes accentuates the positive. “Certain sites have achieved good traction with local government and law enforcement agencies, stabilized hunting, and seen tiger numbers increase. It gives everyone hope to see cases where populations are starting to rebound. Amid all the despair, doom, and gloom, I look for success stories. Let’s understand why they’re working and apply that learning elsewhere.”