HOME

TheInfoList



OR:

Sky islands are
isolated Isolation is the near or complete lack of social contact by an individual. Isolation or isolated may also refer to: Sociology and psychology *Isolation (health care), various measures taken to prevent contagious diseases from being spread **Is ...
mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...
s surrounded by radically different lowland environments. The term originally referred to those found on the Mexican Plateau, and has extended to similarly isolated high-elevation forests. The isolation has significant implications for these natural habitats. The American Southwest region began warming up between and 10,000 years BP and atmospheric temperatures increased substantially, resulting in the formation of vast deserts that isolated the sky islands.
Endemism Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...
, altitudinal migration, and relict populations are some of the natural phenomena to be found on sky islands. The complex dynamics of species richness on sky islands draws attention from the discipline of biogeography, and likewise the
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity' ...
is of concern to
conservation biology Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an ...
. One of the key elements of a sky island is separation by physical distance from the other mountain ranges, resulting in a habitat island, such as a forest surrounded by desert. Some sky islands serve as refugia for boreal species stranded by warming climates since the last glacial period. In other cases, localized populations of plants and animals tend towards
speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution withi ...
, similar to oceanic islands such as the
Galápagos Islands The Galápagos Islands ( es, Islas Galápagos) are an archipelago of volcanic islands in the Eastern Pacific, located around the Equator west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with ...
of
Ecuador Ecuador ( ; ; Quechuan languages, Quechua: ''Ikwayur''; Shuar language, Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechuan ...
.


Etymology

Herpetologist
Edward H. Taylor Edward Harrison Taylor (April 23, 1889 – June 16, 1978) was an American herpetologist from Missouri. Family Taylor was born in Maysville, Missouri, to George and Loretta Taylor. He had an older brother, Eugene. Education Taylor studied at t ...
presented the concept of "Islands" on the Mexican Plateau in 1940 at the 8th American Scientific Congress in Washington, D. C. and his abstract on the topic was later published in 1942.Taylor, Edward Harrison. 1942. ''"Island" faunas on the Mexican Plateau.'' Proceedings of the 8th American Scientific Congress 3: 503-504. The sky island concept was latter applied 1943 when Natt N. Dodge, in an article in '' Arizona Highways'' magazine, referred to the Chiricahua Mountains in southeastern Arizona as a "mountain island in a desert sea". In about the same era, the term was used to refer to high alpine, unglaciated, ancient topographic landform surfaces on the crest of the Sierra Nevada, California. The term was popularized by nature writer Weldon Heald, a resident of southeastern Arizona. In his 1967 book, ''Sky Island'', he demonstrated the concept by describing a drive from the town of Rodeo, New Mexico, in the western
Chihuahuan desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lowe ...
, to a peak in the Chiricahua Mountains, away and higher in elevation, ascending from the hot, arid desert, to grasslands, then to oak-pine woodland, pine forest, and finally to spruce-fir-aspen forest. His book mentions the concept of
biome A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...
, but prefers the terminology of life zones, and makes reference to the work of
Clinton Hart Merriam Clinton Hart Merriam (December 5, 1855 – March 19, 1942) was an American zoologist, mammalogist, ornithologist, entomologist, ecologist, ethnographer, geographer, naturalist and physician. He was commonly known as the 'father of mammalogy', a ...
. The book also describes the wildlife and living conditions of the Chiricahuas. Around the same time, the idea of mountains as islands of habitat took hold with scientists and has been used by such popular writers as David Quammen and
John McPhee John Angus McPhee (born March 8, 1931) is an American writer. He is considered one of the pioneers of creative nonfiction Creative nonfiction (also known as literary nonfiction or narrative nonfiction or literary journalism or verfabula) is ...
. This concept falls within the study of island biogeography. It is not limited to mountains in southwestern North America but can be applied to mountains, highlands, and massifs around the world.


Characteristics

The Madrean sky islands are probably the most studied sky islands in the world. Found in the U.S. states of
New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...
and
Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...
and the Mexican states of
Chihuahua 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 Mun ...
and
Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...
, these numerous mountains form links in a chain connecting the northern end of the
Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American ...
and the southern Colorado Plateau. Sky islands of the central and northern mountains in the United States are often called island ranges, especially by populations within view of such islands of mountains surrounded by plains such as those found within the Wichita Mountains of southwestern Oklahoma. Some more northerly examples are the Crazy Mountains, Castle Mountains, Bears Paw Mountains, Highwood Mountains, and
Little Rocky Mountains The Little Rocky Mountains, also known as the Little Rockies, are a group of buttes, roughly 765 km2 in area, located towards the southern end of the Fort Belknap Indian Reservation in Blaine County and Phillips County in north-central M ...
, all in the US state of
Montana Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North ...
. Each of these ranges is forested and has tundra and snowpack above treeline, but is not connected to any other range by forested ridges; the ranges are completely surrounded by treeless prairie and/or semi-arid scrubland below. Other well-known sky islands of North America are the Great Basin montane forests, such as the White Mountains in California, and the Spring Mountains near
Las Vegas, Nevada Las Vegas (; Spanish for "The Meadows"), often known simply as Vegas, is the 25th-most populous city in the United States, the most populous city in the state of Nevada, and the county seat of Clark County. The city anchors the Las Vega ...
. One of the unique aspects of the sky islands of the U.S.-Mexico border region is the mix of floristic affinities, that is, the trees and plants of higher elevations are more characteristic of northern latitudes, while the flora of the lower elevations has ties to the desert and the mountains further south. Some unique plants and animals are found in these sky islands, such as the mountain yucca,
Mount Graham red squirrel The Mount Graham red squirrel (''Tamiasciurus fremonti grahamensis'') is an endangered subspecies of the southwestern red squirrel (''Tamiasciurus fremonti'') native to the Pinaleño Mountains of Arizona. It is smaller than most other subspecies ...
, Huachuca springsnail, and Jemez Mountains salamander. Some montane species apparently evolved within their current range, adapting to their local environment, such as the Mount Lyell shrew. However, it has also been noted that some isolated mountain ecosystems have a tendency to lose species over time, perhaps because small, insularized populations are vulnerable to the forces of
extinction Extinction is the termination of a kind of organism or of a group of kinds ( taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed ...
, and the isolation of the habitat reduces the possibility of colonization by new species. Furthermore, some species, such as the grizzly bear, require a range of habitats. These bears historically made use of the forests and meadows found in the Madrean sky islands, as well as lower-elevation habitats such as
riparian zone A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ...
s. (Grizzlies were extirpated from the region in the 20th century.) Seasonal movements between highland and lowland habitats can be a kind of migration, such as that undertaken by the mountain quail of the Great Basin mountains. These birds live in high elevations when free of snow, and instead of migrating south for the winter, they migrate ''down''. Confusing the matter somewhat is the potential for an archipelago of sky islands or even the valleys between them to act not only as a barrier to biological dispersal, but also as a path for migration. Examples of birds and mammals making use of the Madrean archipelago to extend their ranges northward are the
elegant trogon The elegant trogon (''Trogon elegans''), also known as the coppery-tailed trogon, is a near passerine bird in the trogon family. Taxonomy ''T. elegans'' has five recognized subspecies In biological classification, subspecies is a rank ...
and white-nosed coati.


List by terrestrial realms


Afrotropical realm

* Cal Madow * Cameroonian Highlands forests * Ethiopian Highlands * Highlands of southern Africa *
Green Mountain Green Mountain is a common name for "The Peak", the highest point on Ascension Island, which has gained some fame for claims that it is one of very few large-scale artificial forests. History and vegetation Many early 19th-century accounts, in ...
of
Ascension Island Ascension Island is an isolated volcanic island, 7°56′ south of the Equator in the South Atlantic Ocean. It is about from the coast of Africa and from the coast of South America. It is governed as part of the British Overseas Territory o ...
* Guinea Highlands **
Nimba Range The Nimba Range forms part of the southern extent of the Guinea Highlands. The highest peak is Mount Richard-Molard on the border of Côte d'Ivoire and Guinea, at 1,752 m (5,750 ft). "Mount Nimba" may refer either to Mount Richard-Mol ...
* Mount Cameroon and Bioko montane forests *
Mount Kilimanjaro Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest free-standing mountain above sea level in the world: above sea level and ab ...
* Mount Gorongosa * Rwenzori Mountains


Australasian realm

*
Mount Wilhelm Mount Wilhelm (german: Wilhelmsberg) is the highest mountain in Papua New Guinea at . It is part of the Bismarck Range and the peak is the point where three provinces, Chimbu Province, Chimbu, Jiwaka Province, Jiwaka and Madang Province, Madang, m ...
* Mount Taranaki * Waitakere Ranges


Indomalayan realm

* Mount Jerai * Fansipan * Jade Mountain * Mount Kinabalu *
Nat Ma Taung Nat Ma Taung ( my, နတ်မတောင်; Khaw-nu-soum or Khonuamthung in Chin), also known as Mount Victoria, is the highest mountain in the Chin State of western Burma. Geography With a height of above sea level and a prominence of , Na ...
*
Central Highlands (Vietnam) Central Highlands ( vi, Cao nguyên Trung phần), Western Highlands ( vi, Tây Nguyên) or Midland Highlands ( vi, Cao nguyên Trung bộ) is one of the regions of Vietnam. It contains the provinces of Đắk Lắk, Đắk Nông, Gia Lai, ...
* Titiwangsa Mountains * Western Ghats


Nearctic realm

* Animas Mountains * Black Range * Capitan Mountains * Chisos Mountains * Colorado Plateau's San Francisco Peaks * Chuska Mountains * Great Basin montane forests * Davis Mountains * Guadalupe Mountains * San Jacinto Mountains * Madrean sky islands * Manzano Mountains * Mogollon Mountains *
Oscura Mountains Oscura Mountains, originally known to the Spanish as the ''Sierra Oscura'', are a ridge of mountains, trending north and south, east of the Jornada del Muerto and west of the Tularosa Valley. It is located in Socorro County and Lincoln County, N ...
*
Olympic Mountains The Olympic Mountains are a mountain range on the Olympic Peninsula of the Pacific Northwest of the United States. The mountains, part of the Pacific Coast Ranges, are not especially high – Mount Olympus is the highest at ; however, the east ...
* Peloncillo Mountains * Quartz Mountains * Sacramento Mountains *
San Augustin Mountains The San Augustin Mountains are a small mountain subrange located at the southern terminus of the San Andres Mountains east of Las Cruces, New Mexico. Description The San Augustin Mountains are only about an long range, trending slightly northe ...
* Sandia Mountains * Spring Mountains * Mount Taylor Volcano * Wichita Mountains


Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bi ...

*
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
**
Sierra de la Laguna The Sierra de la Laguna is a mountain range at the southern end of the Baja California Peninsula in Mexico, and is the southernmost range of the Peninsular Ranges System. It is located in La Paz Municipality and Los Cabos Municipality of sou ...
**
Sierra de Juarez Sierra (Spanish for " mountain range" and " saw", from Latin ''serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieves, a mountain rang ...
** Sierra San Pedro Mártir * Cordillera of Central America * Tepuis * Serra do Mar * Hispaniolan mountain ranges ** Baoruco Mountain Range,
Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...
** Cordillera Central, Dominican Republic ** Massif de la Hotte,
Haiti Haiti (; ht, Ayiti ; French: ), officially the Republic of Haiti (); ) and formerly known as Hayti, is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean Sea, east of Cuba and Jamaica, and ...
** Chaîne de la Selle, Haiti * Sierra de Tamaulipas * Venezuelan Coastal Range


Palearctic realm The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Si ...

* Aïr Mountains * Altai Mountains * Baikal Mountains *
Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range ...
*
Tibesti Mountains The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of and is ...
* Tien Shan


See also

* Altitudinal zonation * Life zone * Holdridge life zones * Inselberg or monadnock * List of life zones by region *
Refugium (population biology) Refugium, plural refugia, the Latin for "refuge" or "hideaway", may refer to: * Refugium (fishkeeping), an appendage to a marine, brackish, or freshwater fish tank that shares the same water supply * Refugium (population biology), a location of a ...
*
Table (landform) A table or tableland is a butte, flank of a mountain, or mountain, that has a flat top. This kind of landform has numerous names, including: * Butte __NOTOC__ In geomorphology, a butte () is an isolated hill with steep, often vertic ...
* Tepui


References

{{reflist, 2


External links


Sky Island Alliance homepage

Sky Islands Traverse long-distance hiking route


Biogeography Biodiversity Endemism Madrean Sky Islands mountain ranges Montane ecology Mountain ranges Landforms