The Sierra del Carmen, also called the Sierra Maderas del Carmen, is a northern finger of the

Sierra Madre Oriental The Sierra Madre Oriental () is a mountain range in northeastern Mexico. The Sierra Madre Oriental is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that f ...

in the state of

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. The Sierra begins at the

Rio Grande The Rio Grande ( and ), known in Mexico as the Río Bravo del Norte or simply the Río Bravo, is one of the principal rivers (along with the Colorado River) in the southwestern United States and in northern Mexico. The length of the Rio G ...

Big Bend National Park Big Bend National Park is an American national park located in West Texas, bordering Mexico. The park has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, and was named after ...

and extends southeast for about , reaching a maximum elevation of . Part of the Sierra del Carmen is protected in the

Maderas del Carmen Maderas del Carmen is a biosphere reserve in the northern Mexican state of Coahuila. Maderas del Carmen encompasses part of the Sierra del Carmen, a northern finger of the Sierra Madre Oriental range. The reserve includes both dry Chihuahuan De ...

Biosphere Reserve as part of a bi-national effort to conserve a large portion of the

Chihuahua Desert Chihuahua may refer to: Places *Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state ** Chihuahua Mu ...

in Mexico and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

Geography

Some authorities include the Chisos and other mountains of Big Bend National Park as part of the Sierra del Carmen. From the Mexican side of the

, the Sierra runs southeast for about to 28’ 40° North latitude and a maximum width of about . Elevations increase toward the south culminating in several peaks with heights of more than and a maximum altitude of .Google Earth The western side of the Sierra del Carmen features a high limestone escarpment that formed along a fault line. Sierra del Carmen1

The Sierra del Carmen is an isolated range, a

sky island Sky islands are topographic isolation, isolated mountains surrounded by radically different lowland environments. The term originally referred to those found on the Mexican Plateau, and has extended to similarly isolated montane ecosystems, hi ...

, that rises above the

. Because of its elevation, higher than any other mountain ranges in the Bolson de Mapimi, the Sierra del Carmen is home to flora and fauna that are more characteristic of the mountains of the western United States and Mexico. At lower elevations, desert vegetation surrounds the higher elevations. Oak and oak-pine forests are found at elevations of . Above , the forest is dominated by pine. Conifer species such as

Douglas fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...

, and Durango fir are found at elevations of or more. The Sierra del Carmen is home to 446 species of birds, 3,600 species of insects, more than 1,500 plant species, and 75 mammals."U.S., Mexico Announce Binational Cooperative Conservation Action Plan" News Release. U.S. Department of the Interior, 24 October 2011 Among the mammals are

American black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

, and

cougar The cougar (''Puma concolor'') is a large Felidae, cat native to the Americas. Its Species distribution, range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mamm ...

. A small subspecies of

white-tail deer The white-tailed deer (''Odocoileus virginianus''), also known as the whitetail or Virginia deer, is a medium-sized deer native to North America, Central America, and South America as far south as Peru and Bolivia. It has also been introduced t ...

, the Carmen Mountains white-tailed deer is found in the Sierra. Extirpated from the region and not at present found in the Sierra are

Grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...

and the

Mexican wolf The Mexican wolf (''Canis lupus baileyi''), also known as the lobo,; nah, Cuetlāchcoyōtl is a subspecies of gray wolf native to southeastern Arizona and southern New Mexico in the United States, and northern Mexico; it also previously rang ...

. There are no rivers, paved highways, or towns in the Sierra, which has been called one of the most remote places on earth."Sky island: El Sierra del Carmen" http://mexicolesstraveled.com/sierradelcarmen.htm, accessed 13 Mar 2013 Drainage of the mountains is by small, mostly ephemeral streams on the east side of the Sierra to the Rio Grande. Off the western side of the Sierra, small streams leaving the mountains disappear quickly in the desert of the Bolson de Mapimi.

Vegetation

According to the International Ecological Classification Standard the vegetation of Sierra del Carmen can be classified as follows Temperate or subpolar needle-leaved evergreen forest Madrean Lower Montane Conifer Forest: Dominant trees are

Arizona pine ''Pinus arizonica'', commonly known as the Arizona pine, is a medium-sized pine in northern Mexico, southeast Arizona, southwest New Mexico, and western Texas in the United States. It is a tree growing to 25–35 m tall, with a trunk diameter of ...

often growing with Chisos red oak, Silverleaf oak and Netleaf oak in association with Poverty oatgrass, Piptochaetium pringlei, Prairie Junegrass,

Little bluestem ''Schizachyrium scoparium'', commonly known as little bluestem or beard grass, is a species of North American prairie grass native to most of the contiguous United States (except California, Nevada, and Oregon) as well as a small area north of t ...

and Bromus lanatipes. ''Madrean Upper Montane Conifer Forest:'' Durango fir and

are the dominant trees growing along

Pinus arizonica ''Pinus arizonica'', commonly known as the Arizona pine, is a medium-sized pine in northern Mexico, southeast Arizona, southwest New Mexico, and western Texas in the United States. It is a tree growing to 25–35 m tall, with a trunk diameter of ...

, Silverleaf oak,

Texas madrone ''Arbutus xalapensis'', commonly known as the Texas madrone, Amazaquitl, or Texas madroño, is a species of flowering plant in the heather family. It is native to Central America, the southwestern United States (western Texas and New Mexico), an ...

in association with Umbellate wintergreen and Piptochaetium pringlei. Sierra Madre Oriental endemic

Pinus stylesii ''Pinus stylesii'' is a species of Pinus, pine in the family Pinaceae, native to the northern Sierra Madre Oriental mountains of northeastern Mexico. A tree reaching , it is a member of Pinus subsection Strobus, ''Pinus subsection ''Strobus''. It ...

grows on the higher elevations,

Chinquapin oak ''Quercus muehlenbergii'', the chinquapin (or chinkapin) oak, is a deciduous species of tree in the white oak group (''Quercus'' sect. ''Quercus''). The species was often called ''Quercus acuminata'' in older literature. ''Quercus muehlenbergii ...

is also common although not dominant component throughout mixed conifer forest to oak-pine forest,

Quaking aspen ''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...

stands exist on moist slopes and canyons, thickets of

Red raspberry ''Rubus idaeus'' (raspberry, also called red raspberry or occasionally European red raspberry to distinguish it from other raspberry species) is a red-fruited species of ''Rubus'' native to Europe and northern Asia and commonly cultivated in othe ...

and hawthorns such as Crataegus tracyi and Crataegus greggiana provide forage for wildlife. Montane or boreal cold-deciduous forest ''Madrean Upper Montane Oak Forest:'' The dominant tree species is Chisos red oak growing among other oaks such as Lacey oak, Arizona white oak, Silverleaf oak in association with Piptochaetium fimbriatum, Piptochaetium pringlei,

Muhlenbergia emersleyi ''Muhlenbergia'' is a genus of plants in the grass family. The genus is named in honor of the German-American amateur botanist Gotthilf Heinrich Ernst Muhlenberg (1753-1815). Many of the species are known by the common name muhly. The greatest ...

Nolina texana ''Nolina texana'', the Texas sacahuiste or Texas beargrass, is a plant in the Asparagaceae, asparagus family that resembles a large clump of grass. It grows in the south central United States and Northern Mexico. They are sometimes grown as a gar ...

and

Temperate broad-leaved evergreen woodland ''Madrean Lower Montane Oak Woodland:'' Silverleaf oak, Arizona white oak,

Quercus grisea ''Quercus grisea'', commonly known as the gray oak, shin oak or scrub oak, is a North American species deciduous or evergreen shrub or medium-sized tree in the white oak group. It is native to the mountains of the southwestern United States and ...

and Emory oak are dominant trees, associates are Netleaf oak, Muhlenbergia glauca, Senecio carlomasonii, Pointleaf manzanita,

, Sideoats grama,

Blue grama ''Bouteloua gracilis'', the blue grama, is a long-lived, warm-season ( C4) perennial grass, native to North America. It is most commonly found from Alberta, Canada, east to Manitoba and south across the Rocky Mountains, Great Plains, and U.S. ...

, Alder-leaf mountain-mahogany,

, Mexican feathergrass and Yucca faxoniana. At least 20 species of oak grow in Sierra del Carmen, making it one of the most oak diverse sky islands, the following have been reported within its boundaries: Arizona oak, Quercus coahuilensis,

Quercus carmenensis ''Quercus carmenensis'', the Mexican oak, is a tree species native to Brewster County, Texas, and Coahuila, Mexico. It grows in pine-oak forests at elevations of . It is a deciduous In the fields of horticulture and Botany, the term ''decid ...

, Emory oak,

Escarpment live oak ''Quercus fusiformis'' (also often referred to as ''Q. virginiana'' var. ''fusiformis''), commonly known as escarpment live oak, plateau live oak, plateau oak, or Texas live oak, is an evergreen or nearly evergreen tree. Its native range inc ...

Gambel oak ''Quercus gambelii'', with the common name Gambel oak, is a deciduous small tree or large shrub that is widespread in the foothills and lower mountains of western North America. It is also regionally called scrub oak, oak brush, and white oak. ...

, Chisos red oak,

, Silverleaf oak, Lacey oak, Mohr oak,

Quercus sinuata ''Quercus sinuata'' is a species of oak comprising two distinct varieties, ''Quercus sinuata'' var. ''breviloba'' and ''Quercus sinuata'' var. ''sinuata'', occurring in southeast North America. Description ''Quercus sinuata'' is a deciduous tr ...

, Sonoran blue oak,

Quercus sideroxyla ''Quercus sideroxyla'', called the Santa Rosa oak and encino colorado, is a species of oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of o ...

, Sandpaper oak, Coahuila scrub oak, Lateleaf oak,

Quercus vaseyana ''Quercus vaseyana'' (also called Vasey oak) is a species of tree in the beech family. It grows in northern Mexico ( Chihuahua, Coahuila, and Nuevo León) and in the US state of Texas. ''Q. vaseyana'' is a shrub or small tree up to 10 metr ...

and Netleaf oak. Temperate or subpolar needle-leaved evergreen woodland ''Madrean Pinyon-Juniper Woodland:''

Mexican pinyon ''Pinus cembroides'', also known as pinyon pine, Mexican pinyon, Mexican nut pine, and Mexican stone pine, is a pine in the pinyon pine group, native to western North America. It grows in areas with low levels of rainfall and its range extends so ...

, Papershell pinyon and Alligator juniper are the most common tree species, along them grow Alder-leaf mountain-mahogany, Sideoats grama,

, Sandpaper oak, Mexican feathergrass and

. Sclerophyllous temperate broad-leaved evergreen shrubland ''Chihuahuan Interior Chaparral:'' Shrubs such as

Fraxinus greggii ''Fraxinus greggii'', the littleleaf ash or Gregg's ash, is a species of flowering plant in the family Oleaceae, native to Texas and Mexico. A xerophytic shrub or scrubby tree reaching , it is suitable for screens and containers. There is a culti ...

, Mohr oak and

grow along Achnatherum eminens,

Agave lechuguilla ''Agave lechuguilla'' (common name in Chihuahua: ''lechuguilla'', meaning "small lettuce") is an ''Agave'' species found only in the Chihuahuan Desert. The plant flowers once in its life and then dies. Description The plant reproduces most ...

, Vauquelinia corymbosa, Desert ceanothus, Alder-leaf mountain-mahogany, Smooth-leaf sotol,

, Yucca faxoniana, Muhlenbergia setifolia and Sideoats grama. Extremely xeromorphic evergreen shrubland ''Chihuahuan Creosotebush Desert Scrub:'' Dominated by

Creosote bush ''Larrea tridentata'', called creosote bush and greasewood as a plant, chaparral as a medicinal herb, and ''gobernadora'' (Spanish language, Spanish for "governess") in Mexico, due to its ability to secure more water by inhibiting the growth of n ...

associated with Whitethorn acacia,

, Bouteloua ramosa, Candelilla, New Mexico rubber plant and

Tiquilia hispidissima ''Tiquilia'' is a genus of flowering plants in the borage family, Boraginaceae. The 27 species in this genus are known by the common name crinklemat. They are native to the Western Hemisphere and are mostly found in desert regions. Selected spe ...

. Extremely xeromorphic deciduous subdesert shrubland Fflou ''Chihuahuan Mixed Desert Scrub:'' Whitethorn acacia, Vachellia neovernicosa, American tarwort,

Ocotillo ''Fouquieria splendens'' (commonly known as ocotillo (), but also referred to as buggywhip, coachwhip, candlewood, slimwood, desert coral, Jacob's staff, Jacob cactus, and vine cactus) is a plant indigenous to the Sonoran Desert and Chihuahuan ...

, Leucophyllum minus and Catclaw mimosa along with Agave havardiana,

Black grama ''Bouteloua eriopoda'', commonly known as black grama, is a perennial prairie grass that is native to the Southwestern United States. Its main means of reproduction is by stolons, as its ratio of viable seeds to sterile ones is naturally low. The ...

Engelmann's prickly pear ''Opuntia engelmannii'' is a prickly pear common across the south-central and Southwestern United States and northern Mexico. It goes by a variety of common names, including desert prickly pear, discus prickly pear, Engelmann's prickly pear in ...

, New Mexico rubber plant, Candelilla,

Aristida purpurea ''Aristida purpurea'' is a species of grass native to North America which is known by the common name purple three-awn. Distribution This grass is fairly widespread and can be found across the western two thirds of the United States, much of ...

, Smooth-leaf sotol, Aloysia gratissima, Sideoats grama,

and Bouteloua ramosa. ''Chihuahuan Mesquite Desert Scrub:'' Dominated by

Honey mesquite ''Prosopis glandulosa'', commonly known as honey mesquite, is a species of small to medium-sized, thorny shrub or tree in the legume family (Fabaceae). Distribution The plant is primarily native to the Southwestern United States and Northern M ...

along with Aloysia gratissima and American tarwort associated with

, New Mexico rubber plant and Tobosa grass. Extremely xeromorphic evergreen subdesert dwarf-shrubland ''Chihuahuan Dwarf Desert Scrub:'' Dominants are

, Candelilla, Smooth-leaf sotol and New Mexico rubber plant associated with Texas false agave and Guayule. Temperate cold-deciduous shrubland ''Madrean Montane Scrub:'' Mainly consists of Alder-leaf mountain-mahogany and Pointleaf manzanita growing with

and Sideoats grama. Temperate or subpolar grassland ''Madrean Mesa-Foothill Grassland:'' This grassland is composed mainly by

, Bouteloua ramosa,

Bouteloua hirsuta ''Bouteloua hirsuta'', commonly known as hairy grama, is a perennial short prairie grass that is native throughout much of North America, including the Great Plains and Canadian Prairies region, as well as Mexico and Guatemala Guatemala ( ...

, Purple three-awn, Bouteloua barbata, Black speargrass, Feather fingergrass and Tobosa grass among other species such as Sideoats grama, Mexican feathergrass,

. Temperate or subpolar grassland with a sparse shrub layer ''Chihuahuan Foothill-Piedmont Desert Grassland:'' Sideoats grama,

, Muhlenbergia setifolia grow along with plants such as Viguiera dentata and rosetophyllus

Yucca thompsoniana ''Yucca thompsoniana'', the Thompson's yucca, is a plant in the family Asparagaceae, native to Texas, Chihuahua and Coahuila.

, Smooth-leaf sotol and

. Gallery forest Riparian communities occur at all elevations and they are usually composed by deciduous species. At higher elevations

Bigtooth maple ''Acer grandidentatum'', commonly called bigtooth maple, is a species of maple native to interior western North America. It occurs in scattered populations from western Montana to central Texas in the United States and south to Coahuila in nort ...

American basswood ''Tilia americana'' is a species of tree in the family Malvaceae, native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Oklahoma, southeast to South Carolina, and west along the Niobrara River to ...

Narrowleaf cottonwood ''Populus angustifolia'', commonly known as the narrowleaf cottonwood, is a species of tree in the willow family (Salicaceae). It is native to western North America, where it is a characteristic species of the Rocky Mountains and the surrounding ...

, Chisos hop-hornbeam, Scouler's willow, Texas ash and

Arizona cypress ''Cupressus arizonica'', the Arizona cypress, is a North American species of tree in the cypress family Cupressaceae, native to the southwestern United States and Mexico. Populations may be scattered rather than in large, dense stands. Descripti ...

. Coming down from the mountains several streams feed the Rio Grande, lining them grow Fremont's cottonwood,

Velvet ash ''Fraxinus velutina'', the velvet ash, Arizona ash or Modesto ash, is a species of '' Fraxinus'' native to southwestern North America, in the United States from southern California east to Texas, and in Mexico from northern Baja California east ...

, Desert willow and

Screwbean mesquite ''Prosopis pubescens'', commonly known as screwbean mesquite, is a species of flowering shrub or small tree in the pea family, Fabaceae, that is native to the southwestern United States (Texas, Arizona, New Mexico, California, southern Nevad ...

Climate

The climate of the Sierra del Carmen is arid to semi-arid with more humid conditions at higher elevations. Annual precipitation is between . Most precipitation is in the summer; snow often falls in the winter. The nearest weather station representative of the Sierra del Carmen is in Big Bend National Park which shares a similar climate. The climatic classification of this station is Bsk (Koppen) or Bsal (Trewartha).

Conservation efforts

The isolation of the Sierra del Carmen and its relatively undisturbed environment has led to conservation efforts in Mexico and jointly with the United States. Much of the Sierra del Carmen has been declared by the government of Mexico the Maderas del Carmen Flora and Fauna Protected Area, a designation which allows many economic activities and private land holdings to continue to exist within the boundaries. The protected area comprises . The Maderas del Carmen is part of a bi-lateral conservation project called the El Carmen—Big Bend Conservation Corridor Initiative which includes contiguous land designated for conservation on both sides of the border totaling more than , an area almost as large as the U.S. state of

Connecticut Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its cap ...

. In 2005, Maderas del Carmen became the first designated

Wilderness area Wilderness or wildlands (usually in the plural), are natural environments on Earth that have not been significantly modified by human activity or any nonurbanized land not under extensive agricultural cultivation. The term has traditionally re ...

Latin America Latin America or * french: Amérique Latine, link=no * ht, Amerik Latin, link=no * pt, América Latina, link=no, name=a, sometimes referred to as LatAm is a large cultural region in the Americas where Romance languages — languages derived f ...

. The Maderas del Carmen Protected Area was created in 1994, although conservation efforts were initially slowed because the land was privately owned, either in large ranches or in the collective farms called

ejido An ''ejido'' (, from Latin ''exitum'') is an area of communal land used for agriculture in which community members have usufruct rights rather than ownership rights to land, which in Mexico is held by the Mexican state. People awarded ejidos in ...

s in Mexico. In 2000 a Mexican corporation, Cementos de Mexico (CEMEX) began to purchase lands for conservation in the region. On CEMEX land livestock and fences were removed and native vegetation encouraged. By 2006, CEMEX owned in or near the Maderas del Carmen and managed another . One of the important characteristics of the Sierra del Carmen is that it functions as a "corridor" enabling wildlife to migrate north and south. In the late 1980s the corridor between the Sierra and the mountains of west Texas enabled the black bear to disperse northward and reestablish itself in Big Bend National Park. The black bear had been extirpated from west Texas in the 1950s. In other initiatives, in 2000, CEMEX in cooperation with conservation organizations in Mexico and Texas began breeding and releasing to the wild

bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subspec ...

which had been absent from the Sierra del Carmen for more than 50 years. On October 24, 2011, Mexico and the United States signed an agreement for "Cooperative Action for Conservation in the Big Bend-Rio Bravo Natural Area of Binational Interest." In 2019, 19 American Bison were reintroduced in the protected area with future plans of releasing more. Bison reintroduction https://www.youtube.com/watch?v=JyN_ozD8WGs

References

{{Mountains of Texas Sierra Madre Oriental Landforms of Coahuila Mountain ranges of Texas Protected areas of Coahuila Nature reserves in Mexico Landforms of Brewster County, Texas