Revillagigedo Isles, Mexico Photograph by Hartmut Walter   Islands of Socorro, Clarion, San Benedicto, and Roc Partida in the Pacific Ocean off the coast of Mexico Tropical and Subtropical Dry Broadleaf Forests   100 square miles (200 square kilometers) -- about the size of Washington DC Critical/Endangered

· The Island Life
· Special Features
· Did You Know?
· Wild Side
· Cause for Concern
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The Island Life

Four oceanic islands were formed by volcanic eruptions on the sea floor millions of years ago: Socorro, Clarion, San Benedicto, and Roca Partida, which collectively make up the Revillagigedo Islands. The isolation of the Revillagigedo Islands in the Pacific Ocean has made them a place of unusual endemism. Between one-fourth and one-half of the plants found on each island, as well as most of the birds and vertebrates that live there, occur nowhere else in the world. These islands also constitute one of the most important nesting, breeding, and foraging sites for four endangered marine turtle species, including leatherback, Pacific olive ridley, green, and hawksbill turtles.

Special Features

The four Revillagigedo Islands are generally quite dry, with a mean annual precipitation of 24 inches (60 cm) per year. The islands are covered by dry forests, with rocky or sandy beaches. Two of the islands--Socorro and Clarion--are also characterized by deep canyons and valleys.

	Island ecosystems are particularly susceptible to damage from introduced species since most of the plants and animals that have evolved on islands are highly specialized and unable to compete with more aggressive invaders. The current wave of extinction around the world has many island species being lost due to this sensitivity.

Wild Side

Dry forests of Dodonea, Prunus, and Opuntia cactus dominate on the islands. In the denser and more humid forest areas high in the mountains, lichens and ferns grow abundantly among trees, with scientific names such as Ilex socorroensis, Guettard insularis, and Bumelia socorrensis. This is the only place in the world where you will find the Socorro dove, parakeet, and wren, and the Socorro Island tree lizard.

Cause for Concern

Over the last 50 years, much of the Revillagigedo dry forests have been destroyed and degraded. One of the biggest threats to the region has been the introduction of certain invasive birds and mammals, as well as domestic sheep and goats. Domestic cats, in particular, have been a big threat to native bird populations and have already hunted the Socorro dove to extinction in the wild. Loss of endemic trees due to sheep grazing threatens the endangered and endemic Socorro mockingbird.

For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.