Sierra Bermeja is a mountain range in southwestern Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

. It covers the area from the Laguna Cartegena

Laguna Cartagena National Wildlife Refuge

The Laguna Cartagena National Wildlife Refuge is a National Wildlife Refuge in Puerto Rico. It is part of the Caribbean Islands National Wildlife Refuge Complex....

 to the north, to the Caribbean Sea

Caribbean Sea

The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....

 to the south. From the Boqueron Forest to the west, to La Parguera to the east. It consists of a combination of volcanic rocks, completely crossed by serpentinite and amphibolite faults, which could well be the oldest known rock in Puerto Rico. The mountains were used by the Taíno people

Taíno people

The Taínos were pre-Columbian inhabitants of the Bahamas, Greater Antilles, and the northern Lesser Antilles. It is thought that the seafaring Taínos are relatives of the Arawak people of South America...

as refuge from the Spanish, and then by smugglers during the Spanish colonization.

The Sierra Bermeja is thought to be the nesting place of many species that feed in the Laguna Cartegena. These hills are among a few forested areas of the southwestern coastal plain, characterized by its aridity. As a result, the Sierra provides the requirements for a large quantity of wildlife established in the area, many of it endangered.

Developments in the region make this area is seriously threatened, even though it is one of the most important natural areas in Puerto Rico.