根據瀕危物種法案(Endangered Species Act.)，美國魚類暨野生動物管理署(U.S. Fish and Wildlife Service)已經為生存受到威脅的北極熊，將超過18.7萬平方英里的陸上島嶼屏障、巢穴區和海上海冰，劃定為關鍵棲息地。此案確定了保育那些需要特殊管理或保護的北極熊所必須的特殊地理區域。
「此關鍵棲息地劃定方案可讓我們與聯邦夥伴一起工作，以確保在其境內的行動不會傷害北極熊族群。不過，北極熊最大威脅是人為活動引起氣候變化造成海冰棲地融化。我們將繼續朝著讓此指標性物種能夠長期生存的策略而努力。」，魚類和野生動物和公園部助理秘書長斯特里克蘭(Tom Strickland)說。
「關鍵棲息地的劃定案明確確定了需要保護的領域，這些區域可讓北極熊在迅速融化的北極生存下來。然而，除非內政部開始認真對待其命令，實際保護北極熊的重要棲息地，要不然，我們編寫的將是這些物種的訃聞，而不是復育計劃。」，生物多樣性中心(Center for Biological Diversity) 資深顧問卡明斯(Brendan Cummings)說。
保育人士說，聯邦機構不得採取任何可能損害或破壞關鍵棲息地的行動。在已劃定關鍵棲息地的物種數目，可能是被復育的2倍多，而如果沒有劃定關鍵棲地的話，其數目可能會下降到一半以下。
劃定關鍵棲息地並不影響土地所有權或建立庇護所、野地、保存、保育或其他保護區。也不允許政府或公眾進入私人土地，除非聯邦投資、許可、或相關活動，關鍵棲息地的劃定並不影響私有地。
2010年11月23日向聯邦法規資料庫(Federal Register)提交含有確定規則(final rule)的最終劃地案，其劃地範圍包括3種地區：島嶼屏障棲息地、海冰棲地和陸上洞穴棲息地。
島嶼屏障棲息地包括沿著阿拉斯加海岸的海岸屏障島嶼和淺灘，主要是當作動物棲身洞穴、和人類保持距離的庇護所、成為撫育幼獸的棲息地和覓食棲地及沿海岸旅行的路徑。
約有96%的面積劃為關鍵棲息地是屬於海冰棲息地。 海冰棲息地位於大陸棚上，包括由從海岸往海外200英里的美國專屬經濟區(U.S. Exclusive Economic Zone)邊緣往外延伸的冰層，這些冰層高過水面984英尺深。
陸地棲息地，包括介於加拿大邊境與卡維克河(Kavik River)之間的阿拉斯加北部20英里的海岸，以及位於卡維克河和阿拉斯加巴羅(Barrow)之間的5英里。
2009年10月29日，該署提案規畫200541平方英里做為北極熊的關鍵棲息地，但確定規則則降到187157平方英里。減少面積的原因是，大半是因為精確反映該提案的海冰棲息地所處的美國邊界，所做的修正。
除此之外，依據確定規則所指定關鍵棲息地，和原始提案有幾個部份不同：
1. 根據綜合自然資源管理計劃(Integrated Natural Resource Management Plans)，有5個美國空軍雷達站可以不受確定規則的規範，此計劃中包含保護北極熊的棲息地若發生在設施範圍內或是鄰近這些設施時的處理方法。
2. 最終劃定區域排除Barrow和Kaktovik的原住民社區。
3. 不論土地所有權狀況，所有現有的人工建築物，都不包括在最終劃定關鍵棲息地。
2008年5月15日根據瀕危物種法案的規範，因為氣候變化而失去海冰棲息地的北極熊屬於受威脅、範圍廣的瀕危物種而受到保護。當時評估的其他威脅包括人類活動的影響，例如，開發石油和天然氣業務、人類藉以維生的捕獵、運輸和旅遊業。其他不會造成北極熊數量顯著下降的活動，由於隨著北極熊數量日減，人類減低這些活動的影響，將變得越來越重要。
The U.S. Fish and Wildlife Service has designated more than 187,000 square miles of on-shore barrier islands, denning areas and offshore sea-ice as critical habitat for the threatened polar bear under the Endangered Species Act.
The designation identifies geographic areas containing features considered essential for the conservation of the bear that require special management or protection.
"This critical habitat designation enables us to work with federal partners to ensure their actions within its boundaries do not harm polar bear populations," said Tom Strickland, assistant secretary for fish and wildlife and parks. "Nevertheless, the greatest threat to the polar bear is the melting of its sea ice habitat caused by human-induced climate change. We will continue to work toward comprehensive strategies for the long-term survival of this iconic species."
"The critical habitat designation clearly identifies the areas that need to be protected if the polar bear is to survive in a rapidly melting Arctic," said Brendan Cummings, senior counsel with the Center for Biological Diversity. "However, unless the Interior Department starts to take seriously its mandate to actually protect the polar bear's critical habitat, we will be writing the species' obituary rather than its recovery plan."
Federal agencies are prohibited from taking any actions that may harm or damage critical habitat. Species that have critical habitat designated are more than twice as likely to be recovering, and less than half as likely to be declining, as those without it, say conservationists.
The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. It does not allow government or the public access to private lands. A critical habitat designation does not affect private lands unless federal funds, permits, or activities are involved.
The final designation, contained in a final rule that was submitted on November 23, 2010 to the Federal Register, encompasses three areas or units: barrier island habitat, sea ice habitat and terrestrial denning habitat.
Barrier island habitat includes coastal barrier islands and spits along Alaska's coast, and is used for denning, refuge from human disturbances, access to maternal dens and feeding habitat and travel along the coast.
About 96 percent of the area designated as critical habitat is sea ice habitat. Sea ice habitat is located over the continental shelf, and includes ice over water up to 984 feet in depth extending to the outer limits of the U.S. Exclusive Economic Zone, 200 miles from shore.
Terrestrial denning habitat includes lands within 20 miles of the northern coast of Alaska between the Canadian border and the Kavik River and within five miles between the Kavik River and Barrow, Alaska.
On October 29, 2009, the Service proposed to designate 200,541 square miles as critical habitat for the polar bear. The final rule reduces this designation to 187,157 square miles, a reduction due mostly to corrections designed to accurately reflect the U.S. boundary for proposed sea ice habitat.
In addition, the critical habitat designated in the final rule differs from that originally proposed in several ways.
‧five U.S. Air Force (USAF) Radar Sites are exempt from the final rule based on their Integrated Natural Resource Management Plans, which include measures to protect polar bears occurring in habitats within or adjacent to these facilities
‧the Native communities of Barrow and Kaktovik were excluded from the final designation
‧all existing manmade structures, regardless of land ownership status, are not included in the final critical habitat designation
The polar bear was protected under the Endangered Species Act as threatened, range-wide, on May 15, 2008, due to loss of sea ice habitat caused by climate change. Other threats evaluated at that time included impacts from activities such as oil and gas operations, subsistence harvest, shipping, and tourism. No other impacts were considered as significant in the decline, but minimizing effects from these activities could become increasingly important for polar bears as their numbers decline.
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