Revillagigedo Islands

The Revillagigedo Islands (or Revillagigedo Archipelago) are a group of islands in the Pacific Ocean. They are part of the Mexican state of Colima and lie 600 km southwest of the Baja California peninsula. The islands are named after Count Revilla Gigedo the son, the 53rd viceroy of New Spain.

The Revillagigedo Islands consist of four volcanic islands: Socorro, Clarión, San Benedicto and Roca Partida. Socorro is the largest island, with an area of 132 km², and its volcanic peak, Mount Evermann, reaches 1130 m in elevation.

History

No evidence of human habitation on the Revillagigedo Islands exists before its discovery by Spanish explorers. Hernando de Grijalva and his crew discovered an uninhabited island on December 21 1533 and named it "Santo Tomé" (Spanish, "Saint Thomas"). Four days later he discovered another, which he named "Inocentes" ("Innocents").

In 1542, Ruy González de Villalobos, while exploring new routes across the Pacific, rediscovered "Inocentes" and changed its name to "Anublada" ("Cloudy"). In 1608, Martín Yañez de Armida, in charge of another expedition, visited Santo Tomé and changed its name to "Socorro" ("Help"). The other two islands were discovered in 1779 by José Camacho. He named the small rocky islet in the middle of the Archipelago "Roca Partida" ("Broken Rock"), and the westernmost island "Santa Rosa" ("Saint Rose"). Santa Rosa was later renamed Clarión ("Clarion").

The Revillagigedo Islands have been visited by a number of other explorers: Domingo del Castillo (1541), Miguel Pinto (1772), Alexander von Humboldt (1811), Benjamín Norell (1825), Sir Edward Belcher (1839) who made the first botanical collections, and Reeve (1848) who witnessed the eruption of Mount Evermann. In 1865, the island was explored by ornithologist Andrew Jackson Grayson, who described the Socorro Dove and Socorro Elf Owl.

On 25 July 1861, President Benito Juárez signed a decree awarding territorial control over the four islands to the state of Colima. His plan was to build an offshore penitentiary on Isla Socorro; although this never happened, the decree whereby they were attached to Colima has never been repealed.

At the beginning of the twentieth century, Dr. Barton Warren Evermann, director of the California Academy of Sciences in San Francisco, California, promoted the scientific exploration of the islands. The most comprehensive biological collections were obtained at this time. The volcano on Isla Socorro was renamed in his honor.

In 1957 the Mexican Navy established a naval base on Socorro, and have had a permanent presence on the island since then. On 21 March 1972, Pablo Silva García became the first governor of Colima to visit his state's island territories. A plaque was unveiled to mark the event and cement Colima's claim.

Ecology

The Revillagigedo Islands are home to many endemic plant and animal species, and are sometimes called Mexico's "little Galapagos". They are recognized as a distinct terrestrial ecoregion, part of the Neotropic ecozone. Socorro is the most diverse in flora, fauna, and topography. The Mexican Government established the islands as a Biosphere Reserve on June 4, 1994.

The unique ecology of the islands is under threat from exotic species. Sheep were introduced to Socorro in 1869. Several endemic species are now threatened with extinction. The Socorro Mockingbird, (Mimodes graysoni) numbers less than 400 individuals. The endemic Socorro Parakeet, (Aratinga brevipes), the Socorro subspecies of the Elf Owl (Micrathene whitneyi graysoni), and Townsend's Shearwater (Puffinus auricularis), are also endangered. The Socorro Dove (Zenaida graysoni) is now extinct in the wild, but is being bred in captivity.

Several organizations are dedicated to halting the destruction of the native ecosystems of the islands. Dr. Harmunt Walter of the University of California, Los Angeles (UCLA) and Dr. Luis F. Baptista of the California Academy of Sciences have coordinated breeding and reintroduction efforts for the Socorro Dove since 1988, through the Island Endemics Institute. The Comite Cientifico para la Conservacion y Restauracion del Archipielago Revillagigedo (Scientific Committee for the Conservation and Restoration of the Revillagigedo Islands) was founded in 1996, and is a committee representing several organizations, including the Island Conservation & Ecology Group, Island Endemics Institute, the University of Missouri - St. Louis (UMSL), the National Autonomous University of Mexico (UNAM) and others. It is chaired by Dr. Walter and Dr. Luis Medrano of UNAM is its secretary. The committee has been advocating removal of the exotic species from the islands, especially the estimated 2000 sheep on Socorro, to allow the islands' ecology to recover, and adoption of a management plan to promote the recovery of the islands' native species, including reintroduction of the Socorro Dove.

External links

Socorro Island: Conserving and Restoring Mexico's Little Galapagos (UCLA website) (http://www.geog.ucla.edu/faculty/socorro.htm)

Island Endemics Institute (http://www.umsl.edu/~s1008864/Endemics.html)

Revillagigedo Archipelago Web ring (UMSL) (http://www.umsl.edu/~s1008864/Revillagigedo_Archipelago.html)es:Archipiélago Revillagigedo de:Revillagigedo-Inseln (Mexiko) nl:Revillagigedo Archipel pt:Ilhas Revilla Gigedo fi:Revillagigedo-saaret