Welcome to Mamirauá Reserve
Nearly enclosed by the Solimões and Japurá rivers, Mamirauá is Brazil’s largest area of intact várzea, a unique forest ecosystem defined by seasonal flooding by sediment-rich ‘white water’ rivers. When the water is high (May to July), there is literally no exposed ground in the 11,400 sq km reserve. As the water recedes, it can leave behind (or strip away) a meter or more of soil. Huge islands form and disappear seasonally, and a house that's built on 8-foot stilts may be at ground level in just a few years. Trees and plants are adapted to live for several months underwater, while normally ground-dwelling animals (from insects to jaguars) spend the same period exclusively in the treetops.
Mamirauá abuts two extractive reserves to the north and west, and the massive Amanã Reserve to the east, which in turn borders Jaú National Park. Altogether, they span around 67,000 square kilometers – nearly the size of Ireland – and form the second-largest block of protected tropical rainforest in the world. (The largest is also in the Amazon, along the Guyana Shield.)
Mamirauá was Brazil’s first 'sustainable development reserve' (there are now more than 20) and is ably managed by the Instituto Mamirauá in Tefé. Sustainable reserves are designed to ensure conservation and scientific research, while promoting sustainable practices and employment for the local population, including ecotourism. There are numerous small communities within the Mamirauá Reserve whose residents work part time as tour guides, cooks, boat drivers, research assistants and nature wardens without abandoning traditional work such as fishing, planting and hunting. Management of the reserve and its primary lodge is due to revert to local control in 2022.
Mamirauá's wildlife is more abundant and less skittish than that in other places. The reserve's signature creature is the uacari (wah-CAR-ee) monkey, endemic to Mamirauá and notable for its crimson face, shaggy white coat and spectacular leaps between trees. Uacaris are highly elusive, though, and spotting one is far from guaranteed. You're much more likely to see howler, capuchin and squirrel monkeys, plus sloths, caimans, dolphins and dozens of bird species, such as macaws, toucans and hoatsin. Manatees and jaguars live in the reserve, too, but are rarely spotted.
High water here is May to July, when the forest is completely flooded and you glide through the water in canoes. (This is not to be confused with rainy season, which runs from December to April.) This is when monkeys and sloths are most visible, and tends to be the busiest time. During low water, roughly September to November, hiking is possible and aquatic animals, especially fish and caimans, are more concentrated.