in the western neighborhood of guaratiba lies the reserva biológica e arqueológica de guaratiba (biological and archeological reserve of guaratiba), now renamed  reserva biológica estadual de guaratiba (state biological reserve of guaratiba) - the 3360 hectares of protected area border the northern side of the marambaia island and the western banks of the sepetiba bay.

It was originally established in 1974 with the goal to preserve the local biomes as well as a number of important archeological sites found in the area - its renaming and reclassification followed an investigation in 2010, when the area gained full protection under the new status of state biological reserve.

the area serves many important functions for the wider region, including flood prevention, provision of environmental services, offering resting and feeding grounds for many species of local wildlife and migratory birds as well  the supply of organic matter, which forms the base of the food chain to the local flora and fauna.