Sky islands are isolatedmountains 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 c. 20,000 and 10,000 years BP and atmospheric temperatures increased substantially, resulting in the formation of vast deserts that isolated the sky islands.[1]Endemism, altitudinal migration, and relict populations are some of the natural phenomena to be found on sky islands.
View of the Santa Rita Mountains across the Tucson valley from the Santa Catalina Mountains. The Santa Ritas are among the most prominent of the "sky islands" in southern Arizona.
The 2,400 m (8,000 ft) Portal Peak in the Chiricahua Mountains surrounded by clouds
The complex dynamics of species richness on sky islands draws attention from the discipline of biogeography, and likewise the biodiversity is of concern to conservation biology. 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, similar to oceanic islands such as the Galápagos Islands of Ecuador.
Herpetologist Edward H. Taylor presented the concept of "Islands" on the Mexican Plateau in 1940 at the 8th American Scientific Congress in Washington, D. C. His abstract on the topic was published in 1942.[2]
The sky island concept was later applied in 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".[3]
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. [4]
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, to a peak in the Chiricahua Mountains, 56 km (35 mi) away and 1,700 m (5,600 ft) 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, but prefers the terminology of life zones, and makes reference to the work of Clinton Hart Merriam. The book also describes the wildlife and living conditions of the Chiricahuas.[5]
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[6] and John McPhee.[7] 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.[8]
Characteristics
View from the Sandia Mountains at 10,378 feet (3,163 m) showing the transition to the desert at 6,000 feet (1,800 m) below
The Madrean sky islands are probably the most studied sky islands in the world. Found in the U.S. states of New Mexico and Arizona and the Mexican states of Chihuahua and Sonora, these numerous mountains form links in a chain connecting the northern end of the Sierra Madre Occidental 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.
View from above 2,100 m (7,000 ft) in the Santa Catalina Mountains, showing pines and snow in the foreground and desert beyond
Some more northerly examples are the Crazy Mountains, Castle Mountains, Bears Paw Mountains, Highwood Mountains, and Little Rocky Mountains, all in the US state of Montana. 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. 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.[9] Some unique plants and animals are found in these sky islands, such as the mountain yucca, Mount Graham red squirrel, 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.[10] 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, and the isolation of the habitat reduces the possibility of colonization by new species.[6] 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 zones. (Grizzlies were extirpated from the region in the 20th century.)[11] 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.[12]
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 and white-nosed coati.[13]
^Favé, M.-J.; Johnson, R. A. (2015). "Past climate change on Sky Islands drives novelty in a core developmental gene network and its phenotype". BMC Evolutionary Biology. 15: 183. doi:10.1186/s12862-015-0448-4. PMC4560157. PMID 26338531.
^Taylor, Edward Harrison. 1942. "Island" faunas on the Mexican Plateau. Proceedings of the 8th American Scientific Congress 3: 503-504.
^ Dodge, Natt (March 1943). "Monument in the Mountain". Arizona Highways. Phoenix, Arizona: Arizona Highway Department. 19 (3): 20–28.
^ Howell, John Thomas (May 1947). "Mono Mesa - Sierra Sky Island". Sierra Club Bulletin. San Francisco, California: Sierra Club. 32 (5): 15–18.
^Heald, Weldon (1967). Sky Island. Princeton, New Jersey: Van Nostrand. pp. 114–126.
^Warshall, Peter (19 September 1994). "The Madrean Sky Island Archipelago: A Planetary Overview". Biodiversity and Management of the Madrean Archipelago. The Sky Islands of Southwestern United States and Northwestern Mexico. Fort Collins, Colorado: United States Forest Service. {{cite journal}}: Cite journal requires |journal= (help)
^McLaughlin, Steven P. (19 September 1994), An Overview of the Flora of the Sky Islands, Southeastern Arizona: Diversity, Affinities, and Insularity, Biodiversity and Management of the Madrean Archipelago. The Sky Islands of Southwestern United States and Northwestern Mexico, Fort Collins, Colorado: United States Forest Service
^"Mountain Quail fact sheet" (PDF). Nevada Department of Wildlife. Retrieved 8 May 2011.
^Tweit, Susan J. (1992). The Great Southwest Nature Factbook. Alaska Northwest Books. pp. 209–210. ISBN978-0-88240-434-9.
^"Davis Mountains Preserve | The Nature Conservancy". www.nature.org.
External links
Sky Island Alliance homepage
January 31, 2023
island, other, uses, disambiguation, isolated, mountains, surrounded, radically, different, lowland, environments, term, originally, referred, those, found, mexican, plateau, extended, similarly, isolated, high, elevation, forests, isolation, significant, impl. For other uses see Sky island disambiguation Sky islands are 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 high elevation forests The isolation has significant implications for these natural habitats The American Southwest region began warming up between c 20 000 and 10 000 years BP and atmospheric temperatures increased substantially resulting in the formation of vast deserts that isolated the sky islands 1 Endemism altitudinal migration and relict populations are some of the natural phenomena to be found on sky islands View of the Santa Rita Mountains across the Tucson valley from the Santa Catalina Mountains The Santa Ritas are among the most prominent of the sky islands in southern Arizona The 2 700 m 9 000 ft Chiricahua Mountains above the desert The 2 400 m 8 000 ft Portal Peak in the Chiricahua Mountains surrounded by clouds The complex dynamics of species richness on sky islands draws attention from the discipline of biogeography and likewise the biodiversity is of concern to conservation biology 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 similar to oceanic islands such as the Galapagos Islands of Ecuador Contents 1 Etymology 2 Characteristics 3 List by terrestrial realms 3 1 Afrotropical realm 3 2 Australasian realm 3 3 Indomalayan realm 3 4 Nearctic realm 3 5 Neotropical realm 3 6 Palearctic realm 4 See also 5 References 6 External linksEtymology EditHerpetologist Edward H Taylor presented the concept of Islands on the Mexican Plateau in 1940 at the 8th American Scientific Congress in Washington D C His abstract on the topic was published in 1942 2 The sky island concept was later applied in 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 3 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 4 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 to a peak in the Chiricahua Mountains 56 km 35 mi away and 1 700 m 5 600 ft 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 but prefers the terminology of life zones and makes reference to the work of Clinton Hart Merriam The book also describes the wildlife and living conditions of the Chiricahuas 5 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 6 and John McPhee 7 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 8 Characteristics Edit View from the Sandia Mountains at 10 378 feet 3 163 m showing the transition to the desert at 6 000 feet 1 800 m below The Madrean sky islands are probably the most studied sky islands in the world Found in the U S states of New Mexico and Arizona and the Mexican states of Chihuahua and Sonora these numerous mountains form links in a chain connecting the northern end of the Sierra Madre Occidental 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 View from above 2 100 m 7 000 ft in the Santa Catalina Mountains showing pines and snow in the foreground and desert beyond Some more northerly examples are the Crazy Mountains Castle Mountains Bears Paw Mountains Highwood Mountains and Little Rocky Mountains all in the US state of Montana 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 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 9 Some unique plants and animals are found in these sky islands such as the mountain yucca Mount Graham red squirrel 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 10 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 and the isolation of the habitat reduces the possibility of colonization by new species 6 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 zones Grizzlies were extirpated from the region in the 20th century 11 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 12 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 and white nosed coati 13 List by terrestrial realms EditThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed October 2016 Learn how and when to remove this template message Afrotropical realm Edit Main article Afromontane Cal Madow Cameroonian Highlands forests Ethiopian Highlands Highlands of southern Africa Green Mountain of Ascension Island Guinea Highlands Nimba Range Mount Cameroon and Bioko montane forests Mount Kilimanjaro Mount Gorongosa Rwenzori MountainsAustralasian realm Edit Mount Wilhelm Mount Taranaki Waitakere RangesIndomalayan realm Edit Mount Jerai Fansipan Jade Mountain Mount Kinabalu Nat Ma Taung Central Highlands Vietnam Titiwangsa Mountains Western GhatsNearctic realm Edit Animas Mountains Black Range Capitan Mountains Chisos Mountains Colorado Plateau s San Francisco Peaks Chuska Mountains Great Basin montane forests Davis Mountains 14 Guadalupe Mountains San Jacinto Mountains Madrean sky islands Manzano Mountains Mogollon Mountains Oscura Mountains Olympic Mountains Peloncillo Mountains Quartz Mountains Sacramento Mountains disambiguation needed San Augustin Mountains Sandia Mountains Spring Mountains Mount Taylor Volcano Wichita MountainsNeotropical realm Edit Baja California Sierra de la Laguna Sierra de Juarez Sierra San Pedro Martir Cordillera of Central America Tepuis Serra do Mar Hispaniolan mountain ranges Baoruco Mountain Range Dominican Republic Cordillera Central Dominican Republic Massif de la Hotte Haiti Chaine de la Selle Haiti Sierra de Tamaulipas Venezuelan Coastal RangePalearctic realm Edit Air Mountains Altai Mountains Baikal Mountains Caucasus Tibesti Mountains Tien ShanSee also EditAltitudinal zonation Life zone Holdridge life zones Inselberg or monadnock List of life zones by region Refugium population biology Table landform TepuiReferences Edit Fave M J Johnson R A 2015 Past climate change on Sky Islands drives novelty in a core developmental gene network and its phenotype BMC Evolutionary Biology 15 183 doi 10 1186 s12862 015 0448 4 PMC 4560157 PMID 26338531 Taylor Edward Harrison 1942 Island faunas on the Mexican Plateau Proceedings of the 8th American Scientific Congress 3 503 504 Dodge Natt March 1943 Monument in the Mountain Arizona Highways Phoenix Arizona Arizona Highway Department 19 3 20 28 Howell John Thomas May 1947 Mono Mesa Sierra Sky Island Sierra Club Bulletin San Francisco California Sierra Club 32 5 15 18 Heald Weldon 1967 Sky Island Princeton New Jersey Van Nostrand pp 114 126 a b Quammen David 2004 The Song of the Dodo Island Biogeography in an Age of Extinctions New York Scribner pp 436 447 ISBN 978 0 684 82712 4 McPhee John 1981 Basin and Range New York Farrar Straus and Giroux pp 46 ISBN 978 0 374 10914 1 Warshall Peter 19 September 1994 The Madrean Sky Island Archipelago A Planetary Overview Biodiversity and Management of the Madrean Archipelago The Sky Islands of Southwestern United States and Northwestern Mexico Fort Collins Colorado United States Forest Service a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help McLaughlin Steven P 19 September 1994 An Overview of the Flora of the Sky Islands Southeastern Arizona Diversity Affinities and Insularity Biodiversity and Management of the Madrean Archipelago The Sky Islands of Southwestern United States and Northwestern Mexico Fort Collins Colorado United States Forest Service Wilson Don Ruff Sue 1999 The Smithsonian Book of North American Mammals Washington D C Smithsonian Institution Press pp 26 ISBN 978 1 56098 845 8 Brown David E 1985 The Grizzly in the Southwest Norman University of Oklahoma Press pp 77 95 136 159 ISBN 978 0 8061 1930 4 Mountain Quail fact sheet PDF Nevada Department of Wildlife Retrieved 8 May 2011 Tweit Susan J 1992 The Great Southwest Nature Factbook Alaska Northwest Books pp 209 210 ISBN 978 0 88240 434 9 Davis Mountains Preserve The Nature Conservancy www nature org External links EditSky Island Alliance homepage Sky Islands Traverse long distance hiking route Saguaro Juniper Corp webpage Retrieved from https en wikipedia org w index php title Sky island amp oldid 1132143404, wikipedia, wiki, book, books, library,
