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Examples Of Refugia In The Northern And Southern Hemispheres
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, August 2012. (462-471) Refugia While most of the biota were driven away from the poles during the glacial advance, there were still isolated areas of sanctuary. These locations are referred to as refugia. A refugiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biota (ecology)
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 term than habitat and can comprise a variety of habitats. While a biome can cover large areas, a microbiome is a mix of organisms that coexist in a defined space on a much smaller scale. For example, the human microbiome is the collection of bacteria, viruses, and other microorganisms that are present on or in a human body. A biota is the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biotas of the Earth make up the biosphere. Etymology The term was suggested in 1916 by Clements, originally as a synonym for '' biotic community'' of Möbius (1877). Later, it gained its c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victoria Land
Victoria Land is a region in eastern Antarctica which fronts the western side of the Ross Sea and the Ross Ice Shelf, extending southward from about 70°30'S to 78°00'S, and westward from the Ross Sea to the edge of the Antarctic Plateau. It was discovered by Captain James Clark Ross in January 1841 and named after Queen Victoria. The rocky promontory of Minna Bluff is often regarded as the southernmost point of Victoria Land, and separates the Scott Coast to the north from the Hillary Coast of the Ross Dependency to the south. The region includes ranges of the Transantarctic Mountains and the McMurdo Dry Valleys (the highest point being Mount Abbott in the Northern Foothills), and the flatlands known as the Labyrinth. The Mount Melbourne is an active volcano in Victoria Land. Early explorers of Victoria Land include James Clark Ross and Douglas Mawson. In 1979, scientists discovered a group of 309 meteorites in Antarctica, some of which were found near the Allan Hills in ... [...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 3,283,000 acres (1,329,000 ha). In 1986, UNESCO declared an area of 57,000 acres (23,000 ha) 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 24,300,000-acre (98,000 km2) 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 2,658,000 acres (1,076,000 ha). Current glaciers cover an area 1,375 square miles ... [...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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin Glaciation
The Wisconsin Glacial Episode, also called the Wisconsin glaciation, was the most recent glacial period of the North American ice sheet complex. 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 alpine glacier advance, known as the Pinedale glaciation. The Wisconsin glaciation extended from approximately 75,000 to 11,000 years ago, between the Sangamonian Stage and the current interglacial, the Holocene. The maximum ice extent occurred approximately 25,000–21,000 years ago during the last glacial maximum, also known as the ''Late Wisconsin'' in North America. This glaciation radically altered the ... [...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 The island is long, wide and has an area of , about one-tenth the size of Ireland and 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. Some 900 people live in Klawock, a long-established village that grew with the fishing industry. Hollis was a boom and bust mining town from 1900 to about 1915. Abandoned, it was re-established as a logging camp in the 1950s. It now has a population of 100 and is the location of the ferry terminal. Mountain peaks, all but the tallest of which were buried by Pleistocene glaciation, reach over . Fjords, steep-si ... [...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 ''tzum'', meaning "spotted" or "marked"; while ''keta'' in the scientific name comes from Russian, which in turn comes from the Evenki language of Eastern Siberia. 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 " hook-snout salmon" ( zh, 钩吻鲑), but is more often called the ''damaha'' fish (), which is borrowed from ''dawa ịmaχa'', the Nanai name of the fish used by the Hezhe minority in northern Northeast China. Description The body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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 be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...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 Southeast ...
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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. 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, which included Forrester Island, Lowrie Island and Wolf Rock. In 1970, the area was designated the Forrester Island Wilderness. The island hosts rookeries of Steller sea lions. The longest recorded migrati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chichagof Island
Chichagof Island (russian: Остров Чичагова), 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 Are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronation Island (Alaska)
Coronation Island is located in Alaska off the northwest coast of Prince of Wales Island, south of Kuiu Island, and west of Warren Island. High prevailing winds and waves from the open ocean to the west, combined with a steep, rocky coast, result in virtually unaccessible shore due to heavy surf along the windward (western and southwestern) coastline of the island. The few protected coves and beaches along the leeward (eastern and northeastern) shore are guarded by rocky shoals. Thus, the island is difficult to access by any route, and is generally limited to small boat or floatplane during brief lulls in the weather. There are no developed facilities and no groomed trails on the island. Wilderness camping is unrestricted and fishing and hunting are allowed. The nearest full-service community is Craig, Alaska. The island is also home to the Coronation Island Wilderness, which encompasses and includes the adjacent Spanish Islands. There are several sea caves on the island, and so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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