Chamela-Cuixmala Biosphere Reserve is located on the Pacific Coast of Mexico, in a mountainous region dominated by rolling hills and alluvial plains. Its climate is hot and humid with an annual median temperature of 24.9 degrees Celsius and well-defined seasons. During the dry season, the lowland forest appears to be lifeless, unappreciated even by some researchers. But, when the rains come, an amazing metamorphosis occurs, life is renewed and the area is cloaked in green. The rainy season lasts from July through October and the dry season is November through June. The median annual precipitation is 748 mm in the hilly Chamela region and 782 mm in the Cuixmala region, which spans from the coast to the mountains. The forest is characterized by its diversity of flora and fauna and a very high number of endemic species. Two groups, the Autonomous University of Mexico (UNAM) and the Cuixmala Ecological Foundation, A.C, own the majority of the land in the reserve. The name of this protected area is derived from the small town of Chamela, which was an important port many decades ago, and the Cuixmala River, which is has the largest water flow of all the rivers in the region and acts as a natural boundary for the reserve.
Chamela-Cuixmala contains 1,149 species of plants including the endemic tree Jatropha chamelensis, the cactus Opuntia excelsa, and other species like Agave colimana. Other studies of the area list 1,877 species of arthropods, 110 species of fish, and 72 species of mammals. The herptofauna consists of 87 species, 68 reptile and 19 amphibian species. The reserve has many important nesting sites for marine turtles, including the green turtle (Chelonia mydas) and the leatherback (Dermochelys coriacea). Also found in the area is the Mexican-bearded lizard (Heloderma horridum), one of only two venomous lizards in the world, and the river crocodile (Crocodylus acutus). All of these species are in danger of extinction. There are 270 bird species, of which 60 percent are residents and the rest are migratory.
The Chamela-Cuixmala Biosphere Reserve is considered vulnerable, which means that there is a high risk that the protected area will not be able to protect or maintain the biological diversity in the long run and therefore requires constant monitoring. The most imminent threats include: highway projects, tourism infrastructure, hunting and wildlife trafficking.