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Examples Of Refugia In The Northern And Southern Hemispheres
A variety of Glacial refugium, glacial refugia have been identified that have allowed animal and plant populations to persist during ice age periods and re-colonize wider areas during post-glacial periods. Background The northern and southern hemispheres of the earth have a dynamic history of advancing and retreating ice sheets. The glacial and interglacial periods are linked to regular eccentricities in the Earth's orbit and correspond to approximately 100 kyr cycles. The advancing, or glacial periods can cause a massive displacement of flora and fauna as it drives them away from the poles, with the most recent glacial maximum having occurred about 20,000 years ago.,Hewitt, Godfrey M. “Some genetic consequences of ice ages, and their role in divergence and speciation.” Biological Journal of the Linnean society. No. 58, 1996. (247-276) Ceridwen et al. “Poleward Bound: biological impacts of southern Hemisphere glaciation.” Trends in Ecology and Evolution. Vol. 27, No. 8, Au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Refugium
A glacial refugium (plural glacial refugia) is a geographic region which made possible the survival of flora and fauna during ice ages and allowed for post-glacial re-colonization. Different types of glacial refugia can be distinguished, namely nunatak, peripheral, and lowland.Holderegger, R., Thiel-Egenter, C. (2009): A discussion of different types of glacial refugia used in mountain biogeography and phytogeography. Journal of Biogeography 36, 476-480. Glacial refugia have been suggested as a major cause of floral and faunal distribution patterns in both temperate and tropical latitudes. With respect to disjunct populations of modern-day species, especially in birds, doubt has been cast on the validity of such inferences, as much of the differentiation between populations observed today may have occurred before or after their restriction to refugia. In contrast, isolated geographic locales that host one or more critically endangered species (regarded as paleoendemics or glacial r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macquarie Island
Macquarie Island is a subantarctic island in the south-western Pacific Ocean, about halfway between New Zealand and Antarctica. It has been governed as a part of Tasmania, Australia, since 1880. It became a Protected areas of Tasmania, Tasmanian State Reserve in 1978 and was inscribed as a UNESCO World Heritage Site in 1997. Macquarie Island is an exposed portion of the Macquarie Fault Zone, Macquarie Ridge and is located where the Australian Plate meets the Pacific Plate. The island is home to the entire royal penguin population during their annual nesting season. Ecologically, the island is part of the Antipodes Subantarctic Islands tundra ecoregion. History 19th century Frederick Hasselborough, an Australian, discovered the uninhabited island on 11 July 1810, while looking for new seal hunting, sealing grounds. He claimed Macquarie Island for United Kingdom, Britain and annexation, annexed it to the colony of New South Wales in 1810. The island was named for Colonel Lachla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shore Pine
''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine, but is rare in lowland rain forests. Like all pines (member species of the genus ''Pinus''), it is an evergreen conifer. Description Depending on subspecies, ''Pinus contorta'' grows as an evergreen shrub or tree. The shrub form is krummholz and is approximately high. The thin and narrow-crowned tree can grow high and achieve up to in diameter at chest height. The ''murrayana'' subspecies is the tallest. The crown is rounded and the top of the tree is flattened. In dense forests, the tree has a slim, conical crown. The formation of twin trees is common in some populations in British Columbia. The elastic branches stand upright or overhang and are difficult to break. The branches are covered with short shoots that are easy to remove. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier Bay
Glacier Bay Basin in southeastern Alaska, in the United States, encompasses the Glacier Bay and surrounding mountains and glaciers, which was first proclaimed a U.S. National Monument on February 25, 1925, and which was later, on December 2, 1980, enlarged and designated as the Glacier Bay National Park and Preserve under the Alaska National Interest Lands Conservation Act, covering an area of . In 1986, UNESCO declared an area of within a World Biosphere Reserve. This is the largest UNESCO protected biosphere in the world. In 1992, UNESCO included this area as a part of a World Heritage site, extending over an area of which also included the Wrangell-St. Elias National Park, Kluane National Park (Canada) and Tatshenshini-Alsek Park (Canada). Part of the National Park is also designated a Wilderness area covering . Current glaciers cover an area and accounts for 27% of the Park area. Up until the early 1700s the area was a large single glacier of solid ice. It has since retre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleasant Island (Alaska)
Pleasant Island (Lingít: ''Wanachích'') is the largest island in the Icy Strait between northern Chichagof Island and the mainland of the Alaska Panhandle. It lies southeast of the mainland city of Gustavus and southwest of the mainland community of Excursion Inlet. Pleasant Island has a land area of 49.192 km² (18.993 sq mi), had no population at the 2000 census, Colter Barnes is the only person who lives here. Location The Pleasant/Lemesurier/Inian Islands Wilderness is located in Icy Strait between Chichagof Island and the mainland on the north end of the Tongass National Forest. The Wilderness is made up of three large islands and a few small islands adjacent to them. Access The wilderness is accessible by boat, kayak or float plane. Area Description This grouping of relatively small islands is unique in that the three largest islands are very different in topography, use and character. Pleasant Island is fairly flat and has a mixture of old-growth forest and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin Glaciation
The Wisconsin glaciation, also called the Wisconsin glacial episode, was the most recent glacial period of the North American ice sheet complex, peaking more than 20,000 years ago. This advance included the Cordilleran Ice Sheet, which nucleated in the northern North American Cordillera; the Innuitian ice sheet, which extended across the Canadian Arctic Archipelago; the Greenland ice sheet; and the massive Laurentide Ice Sheet, which covered the high latitudes of central and eastern North America. This advance was synchronous with global glaciation during the last glacial period, including the North American Glacier#Classification_by_size,_shape_and_behavior, alpine glacier advance, known as the Pinedale glaciation. The Wisconsin glaciation extended from about 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene. The maximum ice extent occurred about 25,000–21,000 years ago during the last glacial maximum, also known as the ''Late W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prince Of Wales Island (Alaska)
Prince of Wales Island (Tlingit: ''Taan'') is one of the islands of the Alexander Archipelago in the Alaska Panhandle. It is the fourth-largest island in the United States (after Hawaii, Kodiak Island, and Puerto Rico) and the 97th-largest island in the world. Geography and ecology Prince of Wales Island is located in the Prince of Wales-Hyder Census Area. It measures long by wide, with an area of , or about one-tenth the size of Ireland (or slightly larger than the state of Delaware). Approximately 6,000 people live on the island. Craig is the largest community; founded as a saltery in the early 20th century, it has a population of 1,500 people. Some 900 more live in Klawock, a long-established village that grew with the boom of the fishing industry. Hollis was a boom-and-bust mining town, most active from 1900 to about 1915. Abandoned, it was re-established as a logging camp in the 1950s; it now has a population of about 100, and is the location of a ferry terminal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chum Salmon
The chum salmon (''Oncorhynchus keta''), also known as dog salmon or keta salmon, is a species of anadromous salmonid fish from the genus ''Oncorhynchus'' (Pacific salmon) native to the coastal rivers of the North Pacific and the Beringian Arctic, and is often marketed under the trade name silverbrite salmon in North America. The English name "chum salmon" comes from the Chinook Jargon term ''tsəm'', meaning "spotted" or "marked"; while ''keta'' in the scientific name comes from Russian language, Russian, which in turn comes from the Evenki language of Eastern Siberia. The term 'Dog Salmon' is most commonly used in Alaska and refers to the Salmon whose flesh Alaskans use to feed their dogs. In Japan, chum salmon is also known as the , or simply , while historically it was known in ''kun'yomi'' as up until the Meiji period. In Greater China, it is known academically as the "kype, hook-snout salmon" ( zh, 钩吻鲑), but is more often called the ''damaha'' fish (), which is loanw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found only 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 elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warren Island (Alaska)
Warren Island is an island in the Alexander Archipelago of southeastern Alaska, United States. It lies on the Pacific coast just southwest of the community of Edna Bay (on Kosciusko Island). Directly west is Coronation Island and directly north is Kuiu Island. Warren Island has a land area of 47.191 km2 (18.22 sq mi) and no permanent resident population. United States Census Bureau The entire island has been designated as the Warren Island Wilderness, a part of Tongass National Forest
The Tongass National Forest () in Southea ...
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Forrester Island (Alaska)
Forrester Island (Haida: ''Gasḵúu'') is an island in the U.S. state of Alaska. It is located off the coast of the Alaska Panhandle, near its southernmost portion, west of Dall Island, in the Prince of Wales-Hyder Census Area. The island is long and covers an area of . It is wooded and mountainous, rising in elevation. In 1970, the area was designated the Forrester Island Wilderness, with in the National Wilderness Preservation System. It is part of the Gulf of Alaska unit of the Alaska Maritime National Wildlife Refuge. Forrester Island was originally named "Santa Cristina" by Juan Pérez in 1774. In 1775, Francisco Antonio Maurelle labeled the island "San Carlos", and in 1778 William Douglas named it "Douglas Island". Royal Navy officer George Dixon named the island "Forrester Island" in 1787, which was the name adopted by George Vancouver on the Vancouver Expedition in 1793. In 1912, U.S. President William Howard Taft signed a law creating the Forrester Island Refuge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chichagof Island
Chichagof Island (), or Shee Kaax, is an island in the Alexander Archipelago of the Alaska Panhandle. At long and wide, it has a land area of , making it the fifth largest island in the United States and the 109th largest island in the world. Its coastline measures 742 miles. There was a 2000 census population of 1,342 persons. It is one of the ABC islands of Alaska. Chichagof Island has the highest population of bears per square mile of any place on Earth.Carol HealyBrown Bear Management Report Alaska Department of Fish & Game, Dec. 2003 Chichagof Island is directly north of Baranof Island, with Peril Strait separating the two islands. It is bounded by Chatham Strait to the east, Icy Strait to the northeast, Cross Sound to the northwest, and the Gulf of Alaska to the west. The communities of Hoonah, Pelican, Tenakee Springs, and Elfin Cove are all located on the northern half of Chichagof Island, in the Hoonah-Angoon Census Area. The island's southern half com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
