消失中的北極 物種滅絕風險正在提高

更新日期:2010/09/20 09:31 洪美惠 摘譯自2010年9月14日ENS美國，加州，舊金山報導；段譽豪編譯；莫聞審校 兩個國際保育機構日前共同發表一份報告指出，不論是狐狸、鯨魚還是海象或浮游生物，北極的生物都被快速的暖化現象推向滅絕之境。 在13日公佈的一份報告中，國際野生動物關懷組織(Care for the Wild International)與生物多樣性中心(Center for Biological Diversity)指出，有17種北極的動物，正在氣候變遷以及海洋酸化的影響下掙扎求生。 受到危害的物種大多是哺乳動物──北極狐、北極熊、北美馴鹿(或馴鹿)、麝牛以及太平洋海象，還有四種鯨魚──灰鯨、白鯨、露脊鯨與獨角鯨。另外有四種海豹也有風險風險，包括了斑環海豹、髯海豹、豎琴海豹與授帶海豹。報告中也將三種海鳥列入危險名單，他們是小嘴斑海雀、白眶絨鴨以及象牙海鷗。此外，一種終生浮游的海生蝸牛──海蝶(sea butterfly)，也有滅絕的風險。 今年以來，西北航道和北海航線大部分都沒有冰，使得來自挪威與俄羅斯的兩隻探險隊伍有機會完成環北極海航行。保育團體指出，這種海冰快速消失與變薄的情形，對依賴海冰生存的物種有破壞性的影響，他們需要海冰育幼、獵食、休息並且躲避天敵。 北極鯨魚的風險則來自因海冰消失而增加的船運，以及近海石油開採活動，這使得漏油、船隻碰撞及噪音導致的風險增加。 海冰減少則迫使太平洋海象媽媽與寶寶靠近海岸，增加了小海象被象群推擠壓死的可能。2008年2月，保育機構「生物多樣性中心」正式提交了一份科學請願書給美國魚類暨野生動物管理局，要求將太平洋海象列入《瀕危物種法》保護名單內。根據一項法律判例，管理局必須在2011年1月31日前做出是否將海象列入保育物種名單的決定。 保育團體的報告指出，海冰太早解體使得斑環海豹與豎琴海豹的小海豹，在長到夠大足以獨立生存前就被迫與母海豹分開。同時間，北極的暖化仍讓北極熊處於危險之中，全世界19個北極熊族群中，有8個正在下降，他們在不斷縮小的冰棚上，掙扎著養育後代。 在陸地上，凍原正向北移動，永凍土的溶解使得溼地變乾，冬天極端的氣候使得北極的麝香牛等草食性動物，因無法取得食物而相繼死亡。 由於體型較大且較具優勢的紅狐北移，北極狐在苔原南部的數量正在下降，而且他們的獵物旅鼠也因為氣溫上升而越來越少。 在冰川附近覓食的海鳥正失去他們攝食與休息的海冰，永凍土的溶化使得他們用以繁殖的溼地變乾。 報告中還說，居住在凍原上的馴鹿與麝香牛，其食物豐富度受到氣溫暖化的影響，極端的氣候現象使得降雪增加，冰塊變硬，令他們難以取得食物。 氣候暖化不僅影響了北極最大的生物，也衝擊到最小的生物。 人類燃燒煤炭、石油與天然氣所排放的二氧化碳，有超過四分之一被海洋所吸收。大量的二氧化碳改變了海洋的化學性質，世界各地的科學家都發現，海洋變酸了。 研究團體在報告中指出，北冰洋現在對有殼的浮游與軟體動物的腐蝕性已經比溫帶水域來得高。對比較敏感的有殼動物而言，2050年以前北冰洋就可能會變得致命，使海洋生態系統面臨崩潰威脅。 「北極生物所面臨的困境，實際上是一個系統性的先期預兆，我們需要政府即刻採取行動，以保護北極生態系統以免崩潰。」國際野生動物關懷組織的計畫主持人瓊斯(Mark Jones)說，「如果我們不做，這影響將會是災難性的，不僅會發生在北極，而會發生在整個地球。」 該報告的結論表示，非常需要以科學為基礎的行動來保護北極野生動物。 生態保育學家建議，大氣中的二氧化碳濃度必須從現在的390 ppm，下降到不超過325至350 ppm，以避免氣候變化與海洋酸化帶來的災難性影響，並且要要恢復北極海冰的面積到25年前的狀況。 為了保護北極物種，這些團體要求減少強力且存在期短的溫室氣體──像是黑碳以及甲烷排放，停止在北極的石油與天然氣開採，並且減少過度獵捕與污染對北極野生動物的威脅。 點擊這裡閱讀報告全文(英文)，《滅絕：不只是北極熊的事》 。Arctic Warms, Sea Ice Shrinks, Extinction Risk GrowsSAN FRANCISCO, California, September 14, 2010 (ENS) From foxes to whales to walruses to plankton, Arctic species are being pushed toward extinction by rapid climate change, finds a new report by two conservation groups. In a report released Monday, the Center for Biological Diversity and Care for the Wild International document the situations of 17 Arctic animals trying to survive the effects of climate change and ocean acidification. Most of the 17 imperiled species are mammals - the Arctic fox, polar bear, caribou or reindeer, muskox, and Pacific walrus, as well as four whales - gray, beluga, bowhead and narwhal. Four ice seals are also at risk - the ringed, bearded, harp and ribbon seals. The report names three seabirds in jeopardy - the Kittlitz's murrelet, spectacled eider and ivory gull; and also finds the sea butterfly, a species of plankton, to be at risk of extinction. This year, the Northwest Passage and the Northern Sea Route are largely free of ice, allowing the potential for a first circumnavigation of the Arctic Ocean now being attempted by two expeditions - one from Norway and one from Russia. The conservation groups say this rapid disappearance and thinning of the sea ice is having devastating effects on the many species that depend on it for rearing young, hunting, resting and avoiding predators. Arctic whales are at risk from increasing offshore oil drilling and shipping activity as areas become ice-free, which heightens threats from oil spills, ship strikes and noise. Sea ice loss is forcing Pacific walrus mothers and calves to come to shore, where young can be trampled to death in stampedes. In February 2008 the Center for Biological Diversity filed a formal scientific petition with the U.S. Fish and Wildlife Service requesting protection of the Pacific walrus under the Endangered Species Act. Under a lawsuit settlement, the Service must make a decision as to whether the species should be protected by January 31, 2011. Early sea-ice breakup prematurely separates ringed and harp seal mothers from their pups before the pups are big enough to survive, the conservation groups report. Meanwhile, the warming Arctic is still putting polar bears at risk. Eight of the world's 19 polar bear populations are declining as they struggle to raise young and hunt for food on shrinking ice sheets. On land, tundra habitat is moving northward, thawing permafrost threatens to drain wetlands, and extreme winter weather events are causing die-offs of Arctic grazers like muskoxen that are prevented from reaching their food. The Arctic fox is disappearing from the southern edge of the tundra as larger, more dominant red foxes move northward and lemming prey grow less abundant as temperatures warm. Seabirds that forage near glaciers and sea ice are losing their feeding grounds and resting places, while thawing permafrost threatens to drain their wetland breeding habitat. Tundra dwellers like the caribou and muskox are being affected by warmer spring temperatures that alter food abundance, as well as extreme winter weather events leaving dense snow and ice crusts that obstruct their access to food, the groups report. Lives of the Arctic's smallest creatures as well as the largest are being disrupted by climate warming. The oceans have absorbed more than a quarter of all of human carbon dioxide emissions - generated by burning coal, oil and natural gas. The addition of this vast quantity of CO2 is changing the chemistry of ocean water, turning it more acidic, scientists around the world have documented. The Arctic Ocean is becoming corrosive to shell-building creatures like plankton and clams more quickly than temperate waters. "It could become lethal to the most sensitive shell-builders by 2050, threatening the marine ecosystem with collapse," the groups state in their report. "The plight of Arctic species is effectively acting as an early warning system. We need our governments to act now to protect the Arctic ecosystem from collapse," said Mark Jones, programs director for Care for the Wild International. "If we don't, the impacts will be devastating, not just for the Arctic, but for the whole planet." The report concludes that science-based actions are urgently needed to protect Arctic wildlife. Atmospheric CO2 must be reduced from its current level of 390 parts per million to, at most, 325 to 350 ppm to avoid catastrophic impacts from climate change and ocean acidification, and to restore Arctic sea ice to the size it was 25 years ago, the conservationists advise. To protect Arctic species, the groups urge the curbing of powerful, short-lived greenhouse pollutants like black carbon and methane, the prevention of new oil and gas development in the Arctic, and the reduction of threats to Arctic wildlife from overhunting and contaminants. Click here to read the report, "Extinction: It's Not Just for Polar Bears." 全文及圖片詳見：ENS報導