The Sierra Madre is a mountain system that is part of the American Cordillera, a chain of mountain ranges that consists of an almost continuous sequence of ranges that form the western backbone of North America, Central America, South America and West Antarctica.
Sierra Madre Mountain System
The Sierra Madre Mountain System is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of ranges.
These mountain ranges form the western backbone of North America, Central America, South America and West Antarctica.
- Sierra Madre Occidental: mountain range in northwestern Mexico
- Sierra Madre Oriental: mountain range in northeastern Mexico
- Sierra Madre de Oaxaca: mountain range in south-central Mexico
- Sierra Madre del Sur: mountain range in southern Mexico
- Sierra Madre de Chiapas: mountain range which extends from southeastern Mexico and crossing southern Guatemala, northern El Salvador, and western Honduras
Sierra Madre Occidental
The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs 1,250 km (780 mi) on a northwest–southeast course parallel to the Pacific coast of Mexico; through northwestern and western Mexico and along the Gulf of California.
The range extends from northern Sonora state near the Mexico-U.S. border at Arizona, southeastwards to the Trans-Mexican Volcanic Belt and Sierra Madre del Sur ranges.
The high plateau that is formed by the range is cut by deep river valleys. This plateau is formed from volcanic rock overlying a basement of metamorphic rock.
This uplift has caused changes in weather patterns; increased rainfall occurring in the mountains has provided areas where ecosystems can form in wetter areas than surrounding land. This water source forms watersheds that provide the arid surroundings with water that makes it possible to irrigate and farm crops.
The wet ecosystems are islands of biodiversity, differing significantly from what would otherwise be a desert landscape. Oak forests are the predominant plant life, and extend into the lowland deserts.
Sierra Madre Oriental
Spanning 1,000 km (620 mi), the Sierra Madre Oriental runs from the Rio Grande — on the border between Coahuila and Texas — south through Nuevo León, southwest Tamaulipas, San Luis Potosí, Querétaro and Hidalgo; to northern Puebla where it joins with the east-west running Eje Volcánico Transversal of central Mexico.
The northernmost are the Sierra del Burro and the Sierra del Carmen which reach the border with the United States at the Rio Grande. North of the Rio Grande, the range continues northwestward into Texas and beyond as the Davis and Guadalupe Ranges.
Mexico's Gulf Coastal Plain lies to the east of the range, between the mountains and the Gulf of Mexico coast. The Mexican Plateau, which averages 1,100 m (3,600 ft) in elevation, lies between the Sierra Madre Oriental and the Sierra Madre Occidental further west. The climate of the Sierra Madre Oriental is drier than the rain forest areas further south.
This long range of tall mountains is noted for its abundant biodiversity and large number of endemic species of plants and wildlife, from the dry north to the wetter south. The Sierra Madre Oriental pine-oak forests are found at high elevations in the range (1,000–3,500 m or 3,300–11,500 ft above sea level).
To the east, the Tamaulipan matorral occupies the range's lower slopes in Nuevo León and northern Tamaulipas, while the Veracruz moist forests cover the lower slopes of the central range, and the eastern slopes at the southern end of the range are home to the Veracruz montane forests.
West of the range, the Mexican Plateau is home to deserts and xeric shrublands, including the Chihuahuan Desert to the north, the Meseta Central matorral on the central part of the plateau, and the Central Mexican matorral on the southern plateau.
Sierra Madre de Oaxaca
The Sierra Madre de Oaxaca mountain range is located in southern Mexico, primarily in the state of Oaxaca, extending north into the states of Puebla and Veracruz.
The mountain range begins at Pico de Orizaba, and extends in a southeasterly direction for 300 km (190 miles) until reaching the Isthmus of Tehuantepec. Peaks in the Sierra Madre de Oaxaca average 2,500 m (8,200 ft) in elevation, with some peaks exceeding 3,000 m (9,800 ft).
The eastern slopes of the range are wetter, intercepting moisture-laden winds from the Gulf of Mexico. A number of drier valleys lie to the west, in the rain shadow of the range.
The Sierra Madre de Oaxaca pine-oak forests ecoregion lies above 1,600 m (5,200 ft) in elevation. The humid Oaxacan montane forests ecoregion lies below 1,600 m (5,200 ft) in elevation, on the eastern slopes above the Veracruz lowlands.
To the east, the xeric Tehuacan Valley matorral ecoregion occupies the Tehuacan Valley to the northwest, the Jalisco dry forests ecoregion occupies the upper basin of the Santo Domingo River, which lies in the rain shadow of the Sierra Madre de Oaxaca.
The southern Pacific dry forests ecoregion lies to the south along the Pacific Coast of Mexico, extending into the upper basin of the Tehuantepec River and the Valley of Oaxaca.
Culturally and geographically, the Sierra Madre de Oaxaca System can be split into many smaller sierras or sub-ranges, each with a unique ecology and human culture.
Sierra Madre del Sur
The Sierra Madre del Sur is located in southern Mexico, extending 1,000 km (620 mi) from southern Michoacán, east through Guerrero, to the Isthmus of Tehuantepec in eastern Oaxaca.
The Sierra Madre del Sur joins with the Eje Volcánico Transversal (Trans-Mexican Volcanic Belt) of central Mexico in northern Oaxaca but is separated from this range further west by the valley of the Río Balsas and its tributary the Río Tepalcatepec.
The mountains' highest point is 3,703 m (12,149 ft), located in central Guerrero. Only one major highway crosses the range between Acapulco and Mexico City. The range is noted for its very high biodiversity and large number of endemic species.
The Sierra Madre del Sur pine-oak forests ecoregion occupies the higher reaches of the range. These forests are part of a chain of Mesoamerican pine-oak forests that stretch from the Southwestern United States to Costa Rica along the American Cordillera.
Lower elevations of the range are covered by tropical dry forests, ecoregions in the tropical and subtropical dry broadleaf forests biome. The Jalisco dry forests occupy the western end of the range's Pacific slope.
The southern Pacific dry forests occupy most of the Pacific slope of the range, from Michoacan in the west through Guerrero and Oaxaca. The basin of the Balsas River, north of the Sierra, is home to the Balsas dry forests.
Sierra Madre de Chiapas
The Sierra Madre de Chiapas is a major mountain range in Central America. The range runs northwest–southeast from the state of Chiapas in Mexico, across western Guatemala, into El Salvador and Honduras. Most of the volcanoes of Guatemala, part of the Central America Volcanic Arc, are within the range.
The range forms the main drainage divide between the Pacific and Atlantic river systems. On the Pacific side the distance to the sea is short, and the streams, while very numerous, are consequently small and rapid. On the eastern side a number of the rivers of the Atlantic slopes attain a considerable volume and size.
The base of many of the volcanic igneous peaks rests among the southern foothills in the southern region of the range.