[1] The reserve holds areas of marshland and coastal Atlantic Forest in good condition.

The golden lion tamarin (Leontopithecus rosalia) and maned sloth (Bradypus torquatus) are endemic.

[1] The União Biological Reserve was created on 22 April 1998 and is administered by the Chico Mendes Institute for Biodiversity Conservation (ICMBio).

The general purpose is to fully preserve biota and other natural attributes in the reserve without direct human interference.

It was created to preserve a fragment of Atlantic Forest and the typical fauna that depends on it, in particular the golden lion tamarin.