Mule Deer and Mountain Sheep
This desert ecoregion is located on the eastern section of Mexico's Baja California peninsula and near-shore islands. The area receives less than 4 inches (100 mm) of precipitation per year, making it among Mexico's most arid regions. Yet in spite of its dry, hot climate, this ecoregion also contains marshes, springs, and pools throughout the peninsula, and is home to a large variety of plants and animals. Mule deer and bighorn sheep can be seen grazing among the desert shrubs or taking drinks from pools in palm-filled canyons.
Despite intense human activity here, the Gulf of California Xeric Scrub ecoregion remains partially intact, although fragile. Because the peninsula is isolated from the rest of the continent, many unique species have evolved here, particularly plants, insects, and reptiles. There are around 238 species of plants, 32 reptiles and amphibians, more than 100 birds, and about 60 mammals. Nine of the species of reptile are endemic. Many of the birds are migratory species, stopping by on their north-south route. Of all the plants found in this area, 20-25 percent are found only in this ecoregion. Several desert tree species grow here, including the palo fierro, or ironwood, and a large number with succulent or thick trunks, such as copol, torote, dipua, cardón, and lomboy. Many desert animals, such as the masked bobwhite quail, pronghorn antelope, and desert bighorn, rely on the ironwood for shelter and food. The Gulf of California islands support many unique species, several of which are found only on one island. These island endemics include a rattlesnake with only one rattle, the giant barrel cactus of Isla Santa Catalina, and five different species of iguana from five different islands.
The puma used to patrol this ecoregion, but it has been heavily hunted and, as a result has been severely reduced in numbers. Reptiles and amphibians fare better, and one might spot a Pacific treefrog or two-striped garter snake in the brush. Bird life is also abundant and key species include the Belding's yellowthroat, least grebe, sora, song sparrow, yellow-breasted chat, red cardinal, and black-fronted hummingbird. Xantu's hummingbird is found only here and in the Cape of Baja. While their populations are threatened, it is still possible to find pronghorn antelopes, mule deer, and bighorn sheep. Additional species common in the Gulf of California scrub are the Baja kangaroo rat and the long-eared myotis, a type of bat.
Cause for Concern
Despite substantial human pressures in and around this ecoregion, large portions are relatively intact. However, it is a very fragile system and vulnerable to cattle grazing, agricultural fires, and increasing tourism activities such as off-road vehicles. In addition, oases are threatened by drainage for farming. Cattle have displaced native animal and plant populations, especially pronghorn antelope, mule deer, mountain sheep, and endemic cacti. Native plant species have been overcome by introduced species, such as buffel grass, in some places. Logging of boojum trees is causing a loss of the species in certain areas. Tourism and the resulting development destroy habitat and pollute surrounding areas. The Belding's yellowthroat has already disappeared from some oases due to human interventions.
For more information on this ecoregion, go to the World Wildlife Fund Scientific Report.All text by World Wildlife Fund © 2001