Walk inland from the beach and the ground stays improbably pale - this is rainforest growing on white sand, a strange marriage of jungle and dune. Screwpines, the spiky Pandanus that gives the canopy its ragged silhouette, dominate the overstory. Tucked among them are enclaves of rare ebony, the dense black-hearted Diospyros prized for centuries, and along the waterways, river mangroves thread their roots through brackish mud. The whole reserve is a mosaic, each patch of habitat hosting its own specialists. It belongs to the greater Sainte Luce forest, which stretches roughly fifteen kilometers up the coast - though that forest is now broken into fragments, separated by cleared land and, crucially, by rivers.

The collared brown lemur, first recorded here in 1990, lives only in this region of Madagascar - a russet-coated primate with the male's namesake collar of pale fur. By night, the forest belongs to others: the fat-tailed dwarf lemur, which can store fat in its tail and enter torpor through the dry season, and the southern woolly lemur, a wide-eyed leaper. Then there is the Sainte Luce mouse lemur. Because rivers cut this reserve off from the neighboring forests, researchers suspect the tiny nocturnal primate here may be an entirely separate, still-unnamed species - evolution quietly diverging in a forest the size of a few city blocks. It is the kind of discovery Madagascar keeps offering: new life, hiding in plain sight.

Some losses are easier to count. The endangered palm Dypsis saintelucei survives at only four sites in all of Madagascar, and fewer than three hundred mature trees remain. They are felled for the materials to build lobster traps that supply nearby hotels - a small, immediate economy pressing against a species' last stand. A larger threat looms over the whole coast. The sands here are rich in ilmenite, the ore that yields titanium dioxide for white paint and plastics, and the multinational mining operation that already works the dunes north of here has set its sights on Sainte Luce. The community has pushed back, declaring its opposition to plans that would tear up the forest and the fishing grounds it depends on.

Since 2010, the Filana Association has managed Sainte Luce as a private reserve - a small nonprofit running on a shoestring and the energy of volunteers. They come to track lemurs, monitor nesting sea turtles, gather seeds, plant trees, and work alongside the surrounding villages. Slash-and-burn farming, known here as tavy, gnaws at the forest edges, and the pressures are relentless. But the reserve is also genuinely idyllic - white sand, warm sea, a canopy alive with calls - and that beauty is part of its defense. As a member of the Lemur Conservation Network, Sainte Luce stakes a claim that this last ribbon of littoral forest, and everything that lives only here, is worth keeping.