非洲白犀牛復育成功 另一亞種卻黯然絕種 | 台灣環境資訊協會-環境資訊中心

非洲白犀牛復育成功 另一亞種卻黯然絕種

2008年06月20日
摘譯自2008年6月17日ENS瑞士,格蘭報導;丁秋仁編譯;蔡麗伶、禾引審校

朗巴國家公園內的北非白犀牛。圖片來源:Kes & Fraser Smith在保育工作的推動下,大部分的非洲犀牛族群數量已有所增加,但絕多數犀牛專家卻推判北非白犀牛已經絕種。

2006年時,曾有人目擊4頭北非白犀牛亞種,但此後在其棲息的剛果國家公園內,卻再也沒有發現北非白犀牛的田野調查記錄。

據世界自然保育聯盟(IUCN)非洲犀牛專家團隊(the African Rhino Specialist Group)所提供的數據顯示在非洲大陸共有超過21,000隻犀牛。其中白犀牛(Ceratotherium simum)亞種總數已從2005年所發現的14,540頭,增加至2007年的17,480頭,然而另一支亞種──北非白犀牛(Ceratotherium simum cottoni),則被列在瀕絕物種的極危名單,數量幾近絶滅。

北非白犀牛現階段正於剛果民主共和國內的加蘭巴國家公園(Garamba National Park)受到保護,2003年4月時曾尋獲30隻北非白犀牛,但因盜獵猖獗,最近一次的發現記錄是在2006年8月所確定的4隻。

非洲黑犀牛。圖片來源:Andrew Gell反觀南非白犀牛亞種數量的逐年增加,被視為保育成功的案例。19世紀末,南非白犀牛一度不樂觀地被誤以為絕種,直至1985年,才於南非夸祖魯-納塔爾省(Kwazulu-Natal)發現為數不到100隻的小族群。在經歷一世紀以來的管理與保護後,南非白犀牛是當今唯一一支非瀕絕的族群。

另一方面,雖然非洲黑犀牛(Diceros bicornis)仍列名於世界自然保育聯盟的極危紅名單,但保育工作在增加數量上亦有斬獲,2005年時記錄到3,730隻,兩年後(2007)已提高至逾4,180隻。

非洲黑犀牛主要分布在辛巴威、南非、納米比亞與肯亞四國,且在數個活動範圍內,數量皆呈成長趨向。所有國家的犀牛繁殖數量逐年上升,唯獨辛巴威的記錄顯示略為下降。

價值不菲的犀牛角常是盜獵者主要的盜取目標,讓犀牛因此成了無辜的槍下亡魂,儘管許多國家已下令嚴格禁止,不過在剛果與辛巴威兩國,犀牛數量減少與盜獵仍有直接關連。

領導非洲犀牛專家團隊的布魯克斯(Martin Brooks)博士表示,「除了不可或缺的盜獵禁令外,建議再搭配有效的犀牛保育工作,包括密集觀察與生物管理,確保每年繁殖率可達5%,屆時特定足夠的數量將可再建立新的族群」。

布魯克斯博士接著說:「其中一項工作重點就是透過世界自然基金會(WWF)野生物分布範圍擴大計畫,將重要的黑犀牛創始種群,成功分置於南非的社區土地,並希望這項方法可適用於其他地區,以提升農村社區對犀牛族群的認同感與保護。」

在犀牛保育研討會中,專家們不但訂立保育工作的優先事項,也為合法與非法買賣犀牛角的挑戰,提出不同的解決方式。北非白犀牛並非處於絕種邊緣的唯一亞種,據世界自然基金會非洲犀牛計畫指出,西非黑犀牛(D. bicornis longipes)的處境一樣危險,而被歸類於可能絕種的名單。

African Rhino Numbers Rise, Yet One Type Sinks Into Extinction
GLAND, Switzerland, June 17, 2008 (ENS)

Populations of most African rhinos are increasing as a result of conservation efforts, but one sub-species, the Northern white rhino, may already be extinct, the world's most expert rhino specialists said today. Just four animals were counted in 2006, but none of these could be found during the most recent fieldwork in the Congolese park where they lived.

There are now more than 21,000 rhinos across Africa, according to figures complied by the African Rhino Specialist Group of the International Union for the Conservation of Nature, IUCN. Numbers of the white rhino, Ceratotherium simum, have increased from 14,540 animals counted in 2005 to 17,480 animals found in 2007, but one of its two subspecies, the Northern white rhino, Ceratotherium simum cottoni, is listed as Critically Endangered and is on the brink of extinction.

Now, the Northern white rhino is restricted in the wild to Garamba National Park in the Democratic Republic of Congo and the only remaining population was reduced by poaching from 30 in April 2003 to only four confirmed animals by August 2006.

By contrast, the other subspecies, the Southern white rhino, is considered one of conservation's greatest success stories. Thought to be extinct in the late 19th century, in 1895 a small population of less than 100 animals was discovered in Kwazulu-Natal, South Africa. After more than a century of protection and management, the southern white rhinos are now the only non-endangered rhinos.

Numbers of the African black rhino, Diceros bicornis, have increased from 3,730 animals found in 2005 to 4,180 counted in 2007, although this species still remains Critically Endangered on the IUCN Red List. The majority of African black rhino can be found in four countries - Zimbabwe, South Africa, Namibia and Kenya - and there are increasing numbers in a number of other range states. All countries with breeding populations have recorded increases, except Zimbabwe, whose numbers are slightly down.

Poaching for rhino horn remains the main threat to rhino survival, and while under control in many countries it has been responsible for losses in both the Democratic Republic of Congo and Zimbabwe. "Even though protection from poaching is critical, effective rhino conservation must also include intensive monitoring and biological management to ensure annual growth rates of at least five percent per year so that surplus rhinos are made available to create new populations," says Martin Brooks, chair of the African Rhino Specialist Group.

"One of the highlights," says Dr. Brooks, "was the first ever introduction of a significant founder population of black rhino to community land in South Africa, made possible through the WWF Wildlife's range expansion project, and hopefully this approach can be applied elsewhere to enhance rhino ownership by rural communities."

Workshops were also held to identify conservation priorities and to address challenges relating to legal and illegal trade. The Northern white rhino is not the only subspecies that is on the brink of extinction. The West African black rhino, D. bicornis longipes, is classified as Probably Extinct, according to the WWF African Rhino Programme.

全文及圖片詳見 ENS