野生瀕危青蛙 再度現身南加州 | 台灣環境資訊協會-環境資訊中心

野生瀕危青蛙 再度現身南加州

2009年07月27日
摘譯自2009年7月23日ENS美國,加州,聖地牙哥報導;張桂芳編譯;蔡麗伶審校

黃腿山蛙。Eugene van der Pijll 攝,USGS 提供。原本被認為是幾乎絕跡的南加州原生青蛙,最近在加州聖貝納迪諾國家森林公園(San Bernardino National Forest)靠近愛德懷鎮(Idyllwild)附近的兩條溪流中再度現身。

黃腿山蛙(Rana muscosa)在聯邦瀕危物種清單榜上有名,被世界自然保育聯盟(IUCN)的瀕危物種紅皮書列為極度瀕危的物種。直到上個月研究人員估計野生環境中只剩122隻黃腿山蛙。

今年6月,兩個各自抱著不同目標的科學團隊分別在聖荷森托荒野(San Jacinto Wilderness)發現了黃腿山蛙。

他們在聖荷森托(San Jacinto)山區的塔克孜(Tahquitz)河和柳樹(Willow)溪中發現這些青蛙,兩個地點相距約2.5英里之遠。至於該地區青蛙的數量則未確定。

再度發現這些青蛙對於透過棲地保護及修復、人工繁殖、野放等方法來達到野外黃腿山蛙復育的政府和非盈利機構合作夥伴而言,的確是意外的收穫。

聖地牙哥(San Diego)動物園開先例,進行人工培育黃腿山蛙的工作。它們最近才剛從蝌蚪蛻變成小青蛙。工作人員的目標是先用人工繁殖的方式培育黃腿山蛙,爾後再將他們野放回原棲地。

基於補償的緣故,美國加州運輸署(Caltrans)出資協助在聖伯納底諾(San Bernadino)山區的330號州道,靠近黃腿山蛙棲地,穩固一處斜坡的緊急施工工程。

加州漁業與動物部(California Department of Fish and Game)正在進行一項有利於安吉樂斯(Angeles)國家森林内小石溪中瀕危黃腿山蛙的移鱒計劃。

鱒魚是在1800年代末期為休閒漁釣而被全面引入湖泊和溪流。然而,蝌蚪往往淪為非本地魚類如鱒魚的腹中物。黃腿山蛙可能花上兩年的時間才長成成蛙,因此之間很長一段時間容易成爲捕食魚類生物的獵物。

小石溪中某一段的鱒魚數量在減少當中,同時那段溪流中的青蛙數量也呈現成長的態勢,因此證明了這種做法是可行的。

由於棲息地消失、氣候變遷效應、農藥污染、致命真菌擴散等原因,全球的青蛙和其他的兩棲動物數量越來越少。

Wild Populations of Endangered Frog Found in Southern California
SAN DIEGO, California, July 23, 2009 (ENS)

A Southern California native frog believed to be nearly extinct has been rediscovered on two creeks in the San Bernardino National Forest near Idyllwild.

The - mountain yellow legged frog, Rana muscosa, is on the federal Endangered Species List and is classed as Critically Endangered by the IUCN Red List of Threatened Species. Until last month researchers had estimated only 122 adult mountain yellow-legged frogs remained in the wild.

In June, two separate groups of scientists pursuing different goals each discovered mountain yellow-legged frogs in the San Jacinto Wilderness.

The frogs were spotted at two locations about 2.5 miles apart in the Tahquitz and Willow creeks in the San Jacinto Mountains. The number of frogs in the area has not yet been determined.

This rediscovery is a windfall for government and nonprofit partners working to increase the number of mountain yellow-legged frogs in the wild by means of habitat protection and restoration as well as a captive breeding and release program.

The San Diego Zoo was the first to breed a mountain yellow-legged frog in captivity. That animal has recently morphed from a tadpole into juvenile frog. The goal of the program is to breed mountain yellow-legged frogs in captivity and return them to their native habitat.

The frog recovery effort is funded by Caltrans to compensate for emergency work to stabilize a slope near the frogs' habitat on state Route 330 in the San Bernadino Mountains.

The California Department of Fish and Game is working towards completion of a trout removal project to benefit the endangered mountain yellow-legged frog in Little Rock Creek in the Angeles National Forest.

Trout were introduced to lakes and streams throughout the region in the late 1800s to benefit recreational fishers. However, tadpoles often become prey to non-native fish such as trout and at the tadpole stage, mountain yellow-legged frogs can take up to two years to mature, so are vulnerable to fish predation for a long period of time.

Trout populations have been reduced in one section of Little Rock Creek and as a result, frogs in that section have increased, demonstrating the success of this approach.

Globally, frogs and other amphibians are on the decline because of habitat loss, the effects of climate change, pesticide contamination and the spread of a deadly fungus.