The 641,284.73 hectares (2,476.0142 sq mi) reserve includes ecosystems with a great wealth of species of biological, economic, scientific and cultural relevance.

Its biological wealth is to be found in the dry forests of its landscape, in the mangroves, the succulent rosette scrubland, the reefs, coasts and pelagic environments it harbors.

In this respect, in order to protect and conserve the reserve’s natural resources and the ecological processes that take place there, it is important to promote sustainable resource use and guarantee ecosystem conservation and integrity to enable the population of the Penitentiary Colony to remain on the island in the long term.

[2] Because of its isolation for over eight million years, Islas Marías' importance as an ecosystem is manifest in its function as a reservoir to Mexico of endemic species.

[2] According to the National Biodiversity Information System of Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO) in Islas Marías Biosphere Reserve there are over 945 plant and animal species from which 29 are in at risk category and 12 are exotics.