Small mountains called “inselbergs” are scattered widely across the central and northern Mozambique landscape. They are crowned by rainforests, which are homes to species that have evolved in isolation for millennia.Inselberg forests are Mozambique’s last inland primary forests. But they’re getting smaller and smaller as humans burn them for agriculture and to flush out game animals, and chop them down for lumber and charcoal.One such inselberg is Mount Nallume, which researchers recently surveyed during a November expedition. While there, they found chameleons that they suspect may be a new speciesHowever, Nallume’s forest is disappearing quickly, with the researchers estimating it may be gone in five to 15 years if deforestation continues at its current rate. They urge the government of Mozambique to do more to protect these “islands in the sky” before they, and the unique animals that live in them, disappear forever. NACOPA, Mozambique — It’s nighttime on Mount Nallume in central Mozambique and the chirping of frenzied crickets fills the thick forest air. Then, toward midnight, another voice joins the cacophony. “I found one!” yells Julian Bayliss to his colleagues Vanessa Muianga and Phil Platts. Muianga is a curator and freshwater expert at the Museum of Natural History in Maputo while Platts and Bayliss are conservation scientists, Platts at the University of York and the IUCN Climate Change Specialist Group, and Bayliss at the African Butterfly Research Institute (ABRI), the Transglobe Expedition Trust and Oxford Brookes University. According to Bayliss, they are the first biologists to set foot on Mount Nallume. They emerge from the underbrush holding a tiny green chameleon just a few inches long. This pygmy chameleon (genus Rhampholeon) holds special significance for the researchers; they suspect it could be a species new to science, one that may live nowhere else in the world except for in this small forest. And soon, Bayliss says, it may live nowhere at all. This chameleon might belong to a species new to science. Photo by Julian Bayliss. Nallume’s forest, home to the chameleon and other wildlife — including more species Bayliss suspects are new to science — is rapidly disappearing as residents from nearby communities chop down its trees for lumber and burn it for food. Bayliss estimates that at its current pace of deforestation, it will be gone in five to 15 years. And it’s not the only one. Dotted throughout the northern half of the country, most of Mozambique’s mountaintop forests are rapidly vanishing as farmers, hunters and loggers hack away their trees for food and money. That’s why Bayliss, Muianga and Platts are here. They are surveying the wildlife of Mount Nallume before it’s too late and the forest and its animals are gone forever. Islands in the sky Nallume’s forests are home to native trees that tower 30 meters (100 feet) above the ground, a height that Platts confirms using measurements from a range finder taken at different spots in the forest. Using a hemispherical camera fitted with a fisheye lens that takes 190-degree images of the canopy from many points within the forest, he is also able to deduce that this forest has a lot more moisture than others in the region. “From these measurements we can work out the amount of leaf area in the forests that relate to the potential of the forests to sequester carbon through photosynthesis,” Platts says, adding that the team will estimate the amount of carbon held by Nallume’s trees when they come back in 2020. This expedition is part of a 15 year-research program of the high altitude mountains of northern Mozambique and the researchers’ desire to see them conserved. In addition to the pygmy chameleon discovered during this trip, many other kinds of animals inhabit these forests; hornbills, bush babies, rabbits, antelope, snails, frogs, spiders, pigs, honey bees, crabs, fish, bats, monkeys and leopards can all be seen here. Bayliss also suspects the existence of another endemic butterfly species. The researchers also suspect they uncovered a new species of butterfly. Photo by David Njagi for Mongabay. Next to the campsite a small stream flows, fed by a swamp that stretches deep into the forest. At night droplets of water from the tree canopy can be heard falling onto pitched tents and the forest floor. Around the forest, bogs form a protective moat. When Bayliss and Platts stop at a clear spot to fly a drone and capture aerial images of the forest; blue swallows circle it, perhaps wondering who the noisy intruder might be. Platts reckons the rare birds have migrated from the Congo Basin and have come here because the rainy season is about to begin. Mount Nallume is what geologists call an “inselberg,” which is basically a small rocky mountain. Typically composed of hard granite in Mozambique, inselbergs formed as the softer land around them eroded away through the millennia, exposing more and more of the hard rock outcrops. Rising up from the flatlands, Mount Nallume is crowned with forest. Photo by Phil Platts. Because of their height, inselbergs are able to trap moisture that the surrounding lowlands cannot, making them ideal spots for forest to grow. These forests are oases for animals and plants that wouldn’t be able to survive in the drier, sparser lowlands. Inselbergs are scattered widely across the central and northern Mozambique landscape, often separated by 16 kilometers (10 miles) or more. Their forests used to be connected, back when the region was cooler and wetter and carpeted in trees. But 10,000 years ago or so the region dried out, confining its lush forests and the animals that lived in them to the tops of mountains where they’ve evolved in isolation ever since. Inselbergs and their unique forests and wildlife aren’t limited to Mozambique, but can be found throughout eastern and southern Africa. Researchers have long known of their potential to harbor undiscovered species, with new chameleons, vipers and other animals regularly uncovered during biological surveys. Bayliss himself has around 20 inselberg expeditions under his belt, most recently to Mozambique’s Mount Lico, which lies about 130 kilometers (80 miles) southwest of Nallume. There, he and his team scaled the steep rock cliffs to the forest above where they claim they found several species new to science, including a butterfly. They spent a total of two weeks in 2018 surveying Lico and another inselberg nearby. For this trip to Nallume and another site, they had less than a week, but are planning a longer, more formal expedition later next year.