Sian Ka'an Biosphere Reserve (Mexico)

Sian Ka'an, which means "Where the Sky is Born" in the Mayan language, lies on the Yucatán coast and houses lush tropical forests, mangroves, marshes, and the world's second largest coastal barrier reef. Sian Ka'an provides habitat for a wide variety of marine, terrestrial, and plant life and a home to Mayan and Mestizo communities of farmers and fishermen. It is under increasing pressure from high-impact, poorly planned tourism development spreading down the coast from Cancun.

El Vizcaino Biosphere Reserve (Mexico)

Centered in the Baja California peninsula, El Vizcaino is a site of stark contrasts. The coastal lagoons are vitally important reproduction and wintering refuges for the gray whale, harbor seal, California sea lion, and northern elephant seal, and habitat for four species of endangered marine turtles. Inland, the arid mountains of the Sierra de San Francisco houses ancient cave paintings. Threats to the ecological health of the reserve include industrial development on its borders, as well as over-fishing and poaching of wildlife.

Tikal National Park (Guatemala)

Sited within Central America's largest contiguous tropical rainforest, the Maya Biosphere Reserve, Tikal was a major site of Mayan civilization, inhabited from the 6th century BC to the 10th century AD. The center of the site contains magnificent temples, palaces and public squares. Currently, poorly managed tourism is degrading Tikal's ecological integrity, while creating few benefits for the surrounding indigenous communities.

Río Plátano Biosphere Reserve (Honduras)

This vast reserve preserves Central America's most important remaining stand of humid tropical forest. It is home to abundant plants and animals and over 2,000 indigenous people, whose traditional lifestyles are threatened by encroaching settlements and agricultural development.

Ujung Kulon National Park (Indonesia)

Just three hours from Jakarta, this park protects natural beauty, unique geologic features, and endangered species. It includes Krakatau, an island important for the study of volcanoes, and the largest remnant of lowland rainforest in the Java plain. Several species of endangered plants and animals occur in the park, including one of the world's two remaining populations of Javan rhinoceros, a species which, at fewer than 50 individuals total, is on the brink of extinction.

Komodo National Park (Indonesia)

Komodo's rugged hillsides of dry savanna contrast starkly with its brilliant white sand coasts and coral reefs. Its volcanic islands house the endangered Komodo dragon, numbered at less than 6,000 individuals. Found nowhere else, this lizard is of great interest to scientists studying evolutionary theory. Komodo is also an important marine reserve, with 1,000 species of tropical fish. A boom in local population (800% growth over the past 60 years) has intensified the environmental pressures on all of Komodo's ecosystems.