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The Plains bison (''Bison bison bison'') is one of two subspecies/ecotypes of the American bison, the other being the wood bison (''B. b. athabascae''). Furthermore, it has been suggested that the Plains bison consists of a northern (''B. b. montanae'') and a southern subspecies, bringing the total to three.〔〔TPWD: News Release ()〕 However, this is generally not supported. A natural population of Plains bison survives in Yellowstone National Park (the Yellowstone Park bison herd consisting of about 3,000 bison) and multiple smaller reintroduced herds of bison in many places in Canada and the United States. ==Near-extinction and reintroduction of herds== At one time, at least 25 million American bison were spread across the United States and Canada. However, by the late 1880s, the total number of bison in the United States had been reduced to fewer than 600 individuals. Most of these were collected onto various private ranches, and the last known free-roaming population of bison consisted of less than 30 in the area which later became Yellowstone National Park. Though it was the official policy of the United States government to minimize or eliminate the bison, and most farmers and ranchers considered bison to be a pest or nuisance, some people were concerned about the demise of this North American icon, so individual landowners took steps to protect a few. Some people saved bison with the express purpose of ranching or hunting them (see Antelope Island bison herd), but some groups such as the American Bison Society were also formed with the idea of saving the species and reintroducing them to at least part of their previous natural range. Plains bison have since been reintroduced into a number of locations around North America. Five main foundation herds of American bison supplied animals intended to save them from extinction.〔Texas Parks and Wildlife ()〕 The northernmost introduction occurred in 1928 when the Alaska Game Commission brought bison to the area of present-day Delta Junction. Bison taken from this transplant were also introduced to other Alaska locations, including Farewell and Chitina.〔(【引用サイトリンク】title=Alaska Hunting and Trapping Information, Alaska Department of Fish and Game )〕 The Delta Junction herd prospered the most, with a population of several hundred throughout the late 20th century. This herd is popular with hunters interested in hundreds of pounds of high-quality meat, but has been a problem for farming operations in the area. Though American bison generally prefer grasslands and plains habitats, they are quite adaptable and live in conditions ranging from desert, as in the case of the Henry Mountains bison herd, to forested areas, such as those of the Yellowstone Park bison herd; yet, they are all of the same subspecies ''Bison bison bison''. Currently, over 500,000 bison are spread over the United States and Canada. However, most of these are on private ranches, and some of them have small amounts of hybridized cattle genes.〔(Remove Threats to Irreplaceable Bison Herd at Wind Cave National Park ). FY 2006 Challenge Cost Share Program. Final Project Report. September 30, 2007. Retrieved on September 16, 2011.〕 Significant public bison herds that do not appear to have hybridized domestic cattle genes are the Yellowstone Park, the Henry Mountains, the Wind Cave, and the Wood Buffalo National Park bison herds and subsidiary herds descended from it in Canada. In 1969, Plains bison from Elk Island National Park were released into Prince Albert National Park in Saskatchewan, creating the Sturgeon River bison herd. At a population around 300 animals, they form a free herd able to wander where they please. The bison are spread throughout Prince Albert National Park's southwestern corner, as well as some crown and private land in the area.〔://www.paherald.sk.ca/News/Local/2013-09-17/article-3393912/Sturgeon-River-plains-bison-population-stabilizing/1/〕 In 2006, Plains bison from Elk Island National Park in Alberta were released into Grasslands National Park in Saskatchewan. This marks the first time Plains bison have wandered the shortgrass prairies of Canada since their near-extinction at the turn of the 20th century. According to the national agency Parks Canada, the entire breeding population of these wild and "semiwild" bison are the descendents of just eight individuals that survived the period of near-extinction, due to overhunting and tuberculosis infecting the herd that the government belatedly attempted to conserve.〔Parks Canada pamphlet titled ''Parks Canada and Plains Bison'', no date, no stated author, available online, ()〕 A herd of about 650 of these animals lives in, and can be seen at, the Wichita Mountains Wildlife Refuge near Lawton, Oklahoma. The herd was started in 1907 with stock from the New York Zoological Park, now known as the Bronx Zoo and located in the Bronx Park. Fifteen animals were shipped to Oklahoma, where bison had already become extinct due to excessive hunting and overharvesting by non-native commercial buffalo hunters from 1874 to 1878.〔(), U.S. Fish and Wildlife Service, Accessed April 21, 2012〕 Some of these specimens have been released in other areas of the United States, such as Paynes Prairie in Florida. Only one Southern Plains bison herd was established in Texas. A remnant of the last of this relict herd had been saved in 1876. "Molly" Goodnight had encouraged her rancher husband, Charles Goodnight, to save some of the last bison which were taking refuge in the Texas Panhandle. By saving these few Plains bison, she was able to establish a buffalo herd near the Palo Duro Canyon. This herd peaked at 250 in 1933.〔John Cornyn, The Winkler Post, Molly Goodnight ()〕 Bison of this herd were introduced into the Yellowstone National Park in 1902 and into the larger zoos and ranches throughout the nation. A herd of around 80 of these animals lives in the Caprock Canyons State Park near Quitaque, Texas, located about 50 miles northeast of Plainview, Texas.〔 In 2013, bison were reintroduced to Fort Belknap Indian Reservation from Yellowstone National Park.〔(Indian Country today 23 August 2013 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Plains bison」の詳細全文を読む スポンサード リンク
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