The last great block of the Atlantic ForestThe Atlantic Forest South-East Reserves — the Reservas de Mata Atlântica do Sudeste — are a group of protected areas in the Brazilian states of São Paulo and Paraná, inscribed by UNESCO as a World Heritage Site in 1999. Together they safeguard one of the largest and most biologically rich surviving stretches of the Mata Atlântica, the coastal rainforest that once ran the length of Brazil's eastern seaboard and has since been reduced to a small fraction of its original cover. Forest on the sea ridgeMost of the protected forest clings to the Serra do Mar, the 1,500-kilometre system of mountain ranges and escarpments that runs parallel to the Atlantic coast of southeastern Brazil, dividing the narrow sea-level littoral from the inland plateau. It was on these steep, cloud-wrapped slopes — hard to clear and hard to reach — that the richest remnants of the Atlantic Forest survived while the lowlands around them were cleared for cities, ports and farms. From the air the contrast is stark: dense, unbroken forest on the escarpment, giving way abruptly to cleared land and urban sprawl below. A living refugeThe reserves span rainforest, mangroves, restinga and offshore islands, and shelter an exceptional concentration of species, many of them found nowhere else. They lie within reach of some of the largest cities in the Southern Hemisphere, including São Paulo and the coastal centres of the Paraná and São Paulo littoral, which makes their survival both remarkable and precarious. Seen from above, they are a green spine holding out against one of the most heavily developed regions of Brazil.