美國家公園 野生動物慘死車輪下 | 環境資訊中心

美國家公園 野生動物慘死車輪下

2013年08月01日
摘譯自2013年7月29日ENS華盛頓報導,姜唯編譯,蔡麗玲審校

大提頓國家公園中穿越馬路的麋鹿(照片由大提頓國家公園提供)。根據美國「環境責任公職人員組織」(PEER)29日公布的統計數字,美國黃石公園、優勝美地和大提頓國家公園中,數以百計的野生動物慘死遊客車輪下。美國國家公園署對此毫無相關政策或規範,僅讓各個國家公園各自管理。

國家公園中野生動物車禍死亡數字不斷攀升,大提頓國家公園已撥出經費分析和研擬解決方案,黃石公園則未提出任何預防措施。

PEER依據《資訊公開法》從各國家公園蒐集的數據顯示,黃石公園平均灰熊車禍死亡數從2000年起十年翻漲一倍,同時期野牛和黑熊車禍死亡數也增加50%。自從黃石公園引進灰狼後,麋鹿、鹿和其他有蹄類動物車禍死亡數隨整體族群數量下降而減少,不過光是2011年就有5隻狼車禍死亡。而優勝美地國家公園從1995年起,已發生300起黑熊車禍,不過沒有其他物種的車禍數據。

隨著大提頓國家公園的野生動物車禍越來越頻繁,園方開始追蹤24個物種的車禍記錄,並分析車禍發生條件-時間、交通流量和車速以及肇事車輛的牌照。園方分析師發現,四分之一的肇事駕駛為本地人,大多是通勤者而非遊客。

PEER執行董事Jeff Ruch指出,「國家公園的野生動物車禍對保育工作的阻礙越來越大」,而且發生原因相當複雜多變。「有時中央分隔島上的植物會吸引動物跨越馬路,因而釀成車禍,死亡動物的屍體又引來食腐動物,可能再次發生慘劇。」Ruch說。雖然三個國家公園發生野生動物車禍的情況類似,他們的應變方式卻大大不同。

黃石公園馬路上的路標(照片由Scott Bothwell提供)。資料指出大提頓國家公園主動積極地嘗試和實施許多解決方案,包括在車禍頻率最高的夜間實施減速規範和各式各樣的路旁標示。「野生動物車禍有顯著的仲夏高峰期,和觀光客的湧入有關係,顯示野生動物車禍數量隨著交通流量變動。」大提頓國家公園分析道。

根據大提頓國家公園數據,「絕大部分的野生動物車禍發生在無雪季節(5至10月),統計分布各個物種不同。麋鹿的顛峰期在6月,叉角羚在7月,鹿則在8月。」

優勝美地2005年曾發起一個遊客教育計畫,在所有有熊發生車禍的地點樹立紅色的標示牌。儘管2005年後熊車禍數字持續升高,園方並沒有深入研究此計畫的成效,甚至還有紅色標示牌被偷走的情形。

黃石公園則沒有針對野生動物車禍採取任何因應措施。園方還曾實施過道路拓寬和增加慢車道等道路工程,導致車速變快。該公園除了瀕危物種法案所要求的檢討報告外,沒有任何研究野生動物車禍或研擬相關對策的紀錄。

PEER正在著手擬訂公園管理者和野生動物保護區經理的指導手冊,詳細列出有效減少野生動物車禍的方法。

Drivers in U.S. National Parks Turn Wildlife Into Road-Kill
WASHINGTON, DC, July 29, 2013 (ENS)

Wild animals in national parks are dying by the hundreds under the wheels of visitors’ cars, according to road-kill records from Yellowstone, Yosemite and Grand Teton national parks released today by Public Employees for Environmental Responsibility, PEER.

The National Park Service has no policies or guidance addressing road-kill, so individual parks are left on their own.

As wildlife-vehicle collisions continue to climb in national parks, Yellowstone takes no preventative measures, while Grand Teton invests financial resources to analyze and reduce these usually fatal interactions.

Documents obtained by PEER under the Freedom of Information Act show that  in Yellowstone National Park, the average number of grizzly bear deaths from vehicle collisions has doubled in the decade since 2000, while collisions involving bison and black bears have risen nearly 50 percent during the same period. Since the introduction of wolves to Yellowstone, road-kill of elk, deer and other ungulates has fallen along with their populations, but wolves now figure in collisions with five wolves killed in 2011 alone.

Yosemite National Park has had 300 collisions with black bears since 1995 but does not systematically collect data on other species, the park reports.

Wildlife are increasingly common casualties of motor vehicle collisions in Grand Teton National Park. Grand Teton tracks vehicle impacts for 24 different species and analyzes the circumstances surrounding accidents – time of day, traffic volume and speed, as well as the car’s license plate. Park analysts discovered that roughly a quarter of the drivers were local residents, who often were commuting rather than sightseeing.

“Road-kill in national parks is a growing conservation failure,” said PEER Executive Director Jeff Ruch, pointing out that the causes of road-kill, other than cars themselves, are varied and complex.

“In some cases, vegetation in the median strip functions like a salad bar drawing animals into harm’s way. Once hit, the resulting carcass attracts scavengers who, in turn, get hit by passing cars,” said Ruch.

While there are similar patterns among these three national parks, their response to vehicular wildlife mortality could not be more different.

Records show that Grand Teton has proactively implemented and tested an array of mitigation measures, including reducing speed limits at night, when most collisions occur, and variable message signs.

“There was a distinct mid-summer peak in WVCs [wildlife-vehicle collisions] that coincided with a peak in visitation, suggesting the number of WVCs is a function of traffic density,” the Grand Teton analysis states.

“The majority of collisions occurred during the snow free months (May-October). Patterns of WVCs varied by species. Collisions with elk peaked in June while pronghorn peaked in July, and those involving deer peaked in August,” according to Grand Teton records.

Yosemite launched a visitor education campaign called “Red Bear, Dead Bear” in 2005, which places red signs along roadways where bears have recently been hit. The park has not studied the program’s effectiveness, although bear deaths continued to rise after 2005, as have the number of red bear signs stolen.

Yellowstone has taken no steps to minimize road kill. The park has made road improvements which have led to higher vehicle speeds, such as widening roads and increasing the number of pull-outs for slower traffic. The park had no record of any study or planning on the issue, aside from reviews required under the Endangered Species Act.

PEER is developing a best practices guide for park superintendents and wildlife refuge managers, detailing the techniques which have successfully reduced road-kill.

※ 全文及圖片詳見:ENS