Sierra Juarez and San Pedro Martir Pine-Oak Forests Ecoregion (Mexico)
The Sierra Juarez and San Pedro Martir pine-oak forests ecoregion is located on the northern part of the Baja Peninsula in northwestern Mexico. The ecoregion covers the higher elevations of these two mountain ranges that are part of the Peninsular Ranges System.
Sierra Juarez and San Pedro Martir Pine-Oak Forests
The Sierra Juarez and San Pedro Martir pine-oak forests ecoregion is part of the temperate coniferous forests biome. It is located in the northern part of the Baja Peninsula in northwestern Mexico.
This relatively small ecosystem is the western equivalent of the "sky islands" of northern Mexico and southwestern Arizona. They are an elevational oasis in a mosaic of chaparral and desert. Rising out of desert lands, the conifer forests are islands of unique species.
The California chaparral and woodlands bound the ecoregion to the west, the Baja California Desert to the southwest, and the Sonoran Desert to the east.
The Sierra Juarez and San Pedro Martir pine-oak forests cover the higher elevations of the Sierra Juárez and Sierra San Pedro Mártir mountain ranges that are part of the Peninsular Ranges System. Both mountain ranges constitute the northernmost elevated peaks of Baja California state, where altitudes range between 1,100 and 2,800 m (3,600 and 9,200 ft) asl.
The granitic mountains in this ecoregion are constituted of young rocky soils that are poorly developed, shallow, and low in organic matter. Among the many rivers which drain the mountain slopes are the Las Palmas, Guadalupe, San Antonio, San Telmo and El Rosario.
The climate here is temperate subhumid, with winter rains and the highest annual precipitation levels in the peninsula, at 400 - 700 mm (15 - 27 in). The higher-than-average rainfall causes this ecoregion to be considered by some researchers to have a more Mediterranean climate, among only a few within Mexico.
Flora and Fauna
The region consists of islands of coniferous forests in an enormous desert of arid terrains; it thus contains a unique biota composed of many endemic and endangered species. The conifer forests are unique to Mexico because they are the only multi-species Mediterranean-climate forests in the country.
The conifer forests in the Sierra de Juárez are among the most important in Mexico because of the diversity of pine trees they contain. At least ten species of Pinus inhabit the steep slopes of the mountains of Baja California.
San Pedro Martir is also home to some of the largest pine trees in Mexico: the Pinus lambertiana at up to 70 m (230 ft) in height, with cones of up to 70 cm (28 in) in length.
Dominant species include the Parry pinyon (Pinus quadrifolia), Jeffrey Pine (Pinus jeffreyi), lodgepole pine (Pinus contorta), sugar pine (Pinus lambertiana), white fir (Abies concolor), and incense cedar (Libocedrus decurrens).
The herbaceous stratum is formed by Bromus sp. and big sagebrush (Artemisia tridentata). Epiphytes and fungi are abundant throughout the forests.
Characteristic mammals include Ornate shrew (Sorex ornatus), puma (Puma concolor), fringed Myotis bat (Myotis thysanodes), California chipmunk (Tamias obscurus), bobcat (Lynx rufus), coyote (Canis latrans), and bighorn sheep (Ovis canadensis).
Birds include the rare bald eagle (Haliaeetus leucocephalus), California condor (Gymnogyps californianus), pinyon jay (Gymnohinus cyanocephalus) and white-breasted nuthatch (Sitta carolinensis).
Many of these forests are still intact, mostly because they are inaccessible. However, cattle farming and intense fires have deteriorated some patches of land. Mistletoe and insects have also invaded and weakened older tree systems.
In 1989 and 1996, fires consumed 27 square miles (70 square kilometers) and 23 square miles (60 square kilometers) of the forest, respectively.
The California condor once roamed the mountains of northern Baja California but disappeared around 1937 because of hunting and poisoning.
Sierra de San Pedro Mártir National Park encompasses 72,909 ha (180,160 acres) within the Sierra de San Pedro Mártir mountain range.