SAMBAVA, Madagascar – One of the best places on Earth to study the natural world has been Madagascar. Seventy percent of its species are found nowhere else — the largest concentration of endemic wildlife anywhere. In the past 10 years alone, scientists have discovered 40 mammals, 69 amphibians, 61 reptiles, 42 invertebrates and 385 plants in the country. Its parks are ecotourism destinations and points of national pride.

With the world’s largest concentration of endangered species, Madagascar is also a leading place to study extinction. Last year the country lost the greatest percentage of primary forest, making it one of the most deforested places on Earth. Since 2012 the International Union for Conservation of Nature has named lemurs, which are found only in Madagascar, as the world’s most endangered group of animals, with 95% either threatened or endangered.

Poaching, farming, charcoal cultivation and illegal logging have placed enormous pressure on wildlife. The next looming danger is climate change; warming temperatures threaten to push wildlife out of conservation areas. The land they set aside yesterday might not be right for tomorrow, requiring scientists to think outside traditional park borders.

“Parks and large tracts of land are the core of how we save stuff,” said Timothy Male, the executive director of a Washington think tank called the Environmental Policy Innovation Center. But, he added, small, local parks “tend to be where a lot of dynamism happens.”

The Sambava region is home to both sprawling national parks and a growing network of locally run reserves. For decades, many forests were protected simply by their hillsides. But in the past five years, prices for vanilla, which thrives on slopes, have increased tenfold to $300 per pound, prompting a rush for hillside land.

Erik Patel, a primatologist with Lemur Conservation International, and Desiré Rabary, a conservationist and a manager in the organization, are trying to document how many lemurs remain in the region and where they are, sometimes one animal at a time.

Both said that the most important questions in conservation today lie outside the large protected areas like nearby Makira Natural Park, a rainforest larger than Yosemite National Park. Although these are crucial refuges, Patel said, half of the remaining rare lemurs, including the silky sifaka, indri and ruffed lemur, eke out their survival in smaller, less pristine places.

As habitats shift with the climate, these marginal populations may become just as important to species survival as those in the large parks.

Patel is hoping that the lemurs of northern Madagascar might persist in small groups and preserve their genetic diversity against the odds.

The hike to Antohakalava takes three days. From a distance the land looks forested and green. But where huge forests once stood, the land has been clear-cut for fields or charcoal.

Silky sifakas are picky about their habitat, but Patel said he had been surprised by where they can survive. The previous year he found them occupying narrow strips of trees next to farms. By comparison, Antohakalava was a lemur paradise.

The owner of Antohakalava is Ratombo Jaona, a vanilla broker. He bought the land a decade earlier for plantations but quickly learned that cutting primary forest so close to Makira might attract unwanted government attention. Instead, he considered ecotourism.

“I can’t even think of another forest that has all three critically endangered lemurs,” Patel said. “We’ve seen a lot of benefits from these small, private parks that are kind of filling in the gaps. These are people that seem to really want to protect land. And it seems to be a model that’s growing.”