全世界1/5種植物難保! 10月生物多樣性峰會路艱難 | 台灣環境資訊協會-環境資訊中心

全世界1/5種植物難保! 10月生物多樣性峰會路艱難

2010年10月01日
摘譯自2010年9月29日ENS英國,倫敦報導;段譽豪編譯;蔡麗伶審校

植物學家洛夫勒(Linda Loffler)與來自南非的瀕臨滅絕山藥,Dioscorea strydomiana。由於被認為對癌症具有療效,有200種植物被採集者鎖定,切下它們的塊莖。(圖片來源:John Burrows,皇家植物園,邱園)生物多樣性專家在首次對全世界大約38萬種植物滅絕風險分析後,於9月29日發表報告指出,每5種植物就有一種面臨滅絕危機。大部分受威脅的物種都是熱帶種類。而最大的威脅來自人類活動造成的棲地破壞,主要是將自然棲地改造城農地或是畜養牲畜之用。

這份報告是為了各國政府將在10月中,於日本名古屋所舉辦的聯合國生物多樣性高峰會作準備,屆時將訂定新的保育目標。

英國環境大臣斯皮爾曼(Caroline Spelman)表示,「對下個月要在名古屋舉辦的國際生物多樣性會議而言,這份報告出現的時機十分重要,全世界有1/5的植物因為人類活動而面臨滅絕的消息,令人十分不安。植物對人類的生存至關重要,提供了食物、飲水以及藥物,也能減輕並調適氣候變遷。」英國皇家植物園(邱園)主任霍珀教授(Stephen Hopper)則表示,「這是第一次我們對全球植物的滅絕風險有清楚的認識。」

2010生物多樣性目標  延至2020

來自邱園、美國自然史博物館以及IUCN專家小組的科學家們,對具有世界代表性的植物進行了一項評估,以響應聯合國的2010國際生物多樣性目標。

2010年生物多樣性目標訂於2002年4月訂定,生物多樣性公約締約國承諾,要在2010年以前大幅降低全球生物多樣性的流失,不論是在全球、區域或是國家尺度上,以扶助貧窮的方式造福全地球上的生命。 這項目標已經在永續發展世界峰會以及聯合國大會中通過,並成為千禧發展目標(Millennium Development Goals)下的一個新目標。

但是在4月份的一份報告結論指出,有30項指標顯示世界各國領導人未能在2010年以前減少生物多樣性的流失,反而眼睜睜的看著生物多樣性下降。

下個月在名古屋的會議將嘗試設定新的2020年生物多樣性目標,在2020年以前阻止生物多樣性的喪失以及生態系的退化,並且在可行的範圍內將之恢復。「所討論的2020生物多樣性目標雖然龐大,但是考量生物多樣性隨著時間的流失,我們必須更加努力。」霍珀說。「植物是生物多樣性的基礎,它們在不確定的氣候、經濟以及政治時代上的重要性已經被忽視太久。」

生物受威脅持度:兩棲、珊瑚>植物=哺乳類>鳥類

29日公佈的評估顯示,植物受到的威脅程度與哺乳動物相當,比鳥類要嚴重,但是沒有兩棲類和珊瑚嚴重。

為了準確評估植物在全世界各地的狀況,科學家針對一般及珍稀的物種都進行了評估。

受到最大威脅的棲地是熱帶雨林。這項研究指出,目前因熱帶雨林流失加快所產生的碳排放,佔了全球的20%。

裸子植物所面臨的威脅是最大的。這些植物的種子裸露沒有果實保護,包括針葉樹、蘇鐵、銀杏和熱帶常綠喬木、灌木和藤本植物等稱為買麻藤(gnetales)。這些植物的種子烘烤後可以食用,葉片也可以作為蔬菜,有些則具有醫藥用途。

「科學家估計,全世界可能有500萬到5000萬種植物,但現在人類發現的只有不到200萬種,利用新的方法,我們可以改進評估開花植物種類數目的方法,並計算還有多少種類仍不為人知。」英國劍橋微軟研究所的報告主要作者亞伯(Lucas Joppa)如此表示。

這株矮棕櫚Dypsis brevicaulis來自馬達加斯加,受到森林的破壞的威脅。野外發現的植株數:不到50株。(圖片來源:John Dransfield,皇家植物園,邱園)

根據皇家植物園的世界植物科名清單資料,科學家算出開花植物的數目,比先前估計的要多出10%至20%。這項研究成果發表在《皇家學會論文集B》(Proceedings of the Royal Society B)。

科學家們不斷的發現新的植物。邱園的科學家過去一年在喀麥隆大片的熱帶雨林內,發現了250種新發現或是新描述的植物物種。

其中最高大的植物是由麥金德博士(Barbara Mackinder)命名的Berlinia korupensis,高達42公尺。這種與豌豆同類的植物會開美麗的白花並結出巨大的豆莢,在成熟時裂開將種子推離母株。

這次在喀麥隆魯普國家公園(Korup National Park)的調查顯示,這種植物極其稀有。「我們的調查中只發現了17株,」邱園的伯特(Xander van der Burgt)說。「儘管魯普國家公園受到保護,但是Berlinia korupensis仍然因為人類對公園產生的壓力而瀕臨滅絕。」

29日公佈的評估結果已經登錄到植物紅皮書採樣指數(Sampled Red List Index for Plants)內,這個指數分析了大量來自世界各地的植物樣本。

植物紅皮書採樣指數是IUCN(世界自然保育聯盟)權威性的紅皮書的一部分,紅皮書是世界各地學者專家付出努力,建立的一套監視世界各主要動植物以及真菌族群變化的工具。

霍珀表示,「我們不能坐視植物消失-植物是地球上所有生命的基礎,提供乾淨的空氣、水、食物與能源。所有的動物與鳥類都依賴植物生存,我們人類也是。現在比以往更需要取得扭轉生物多樣性流失的工具,而植物紅皮書採樣指數對保育人士以及科學家而言,就是這樣的工具之一。」

One-fifth of All Plant Species at Risk of Extinction
LONDON, UK, September 29, 2010 (ENS)

One in every five of the world's plant species is threatened with extinction, biodiversity experts said today in the first global analysis of extinction risk for the world's estimated 380,000 plant species.

Most of the threatened species are found in the tropics, the report shows. The greatest threat is habitat loss caused by human activities, mostly the conversion of natural habitats for agriculture or livestock use.

The analysis was released today as governments prepare to meet in Nagoya, Japan in mid-October to set new conservation targets at the United Nations Biodiversity Summit.

"This report comes at an important time in the lead up to the major international biodiversity meeting in Nagoya next month," said UK Environment Secretary Caroline Spelman. "It is deeply troubling that a fifth of the world's plants are facing extinction because of human activity. Plant life is vital to our very existence providing us with food, water, medicines, and the ability to mitigate and adapt to climate change."

For the first time we have a clear global picture of extinction risk to the world's known plants," said Professor Stephen Hopper, director of the Royal Botanic Gardens, Kew.

Scientists from the Kew, the Natural History Museum and the IUCN Specialist Groups assessed a representative sample of the world's plants, in response to the United Nations' International Year of Biodiversity and the 2010 Biodiversity Target.

The 2010 Biodiversity Target was set in April 2002, when the governments that are Parties to the Convention on Biological Diversity committed themselves to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national levels as a contribution to poverty alleviation and to the benefit of all life on Earth.

This target was endorsed by the World Summit on Sustainable Development and the United Nations General Assembly and was incorporated as a new target under the Millennium Development Goals.

But in April, a report on over 30 indicators concluded that world leaders have failed to reduce the global rate of biodiversity loss by 2010 and have instead overseen biodiversity declines.

Next month the meeting in Nagoya will attempt to set a 2020 biodiversity target that will likely be to halt biodiversity loss and the degradation of ecosystems services by 2020, and to restore them wherever feasible.

"The 2020 biodiversity target that will be discussed in Nagoya is ambitious, but in a time of increasing loss of biodiversity it is entirely appropriate to scale up our efforts," said Hopper. "Plants are the foundation of biodiversity and their significance in uncertain climatic, economic and political times has been overlooked for far too long."

The assessment released today shows that plants are more threatened than birds and as threatened as mammals, but plant species are less threatened than amphibians or corals.
Both common and rare species were assessed in order to give an accurate picture of how plants are faring around the world.

The most threatened habitat is tropical rainforest. The study points out that the current rate of loss of tropical forest accounts for 20 percent of global carbon emissions.

Gymnosperms are the most endangered plant group. These seed-bearing plants whose seeds do not form inside fruits but outside, include conifers, cycads, ginkgo and the tropical evergreen trees, shrubs and lianas called gnetales. Many of these gnetum species are edible, as the seeds are roasted, and the foliage is used as a vegetable. Some are valued as herbal medicine.

"Scientists have estimated that, overall, there could be between 5 million and 50 million species, but fewer than two million of these species have been discovered to date," said lead author Lucas Joppa of Microsoft Research in Cambridge, UK. "Using novel methods, we were able to refine the estimate of total species for flowering plants, and calculate how many of those remain undiscovered."

Based on data from the online World Checklist of Selected Plant Families at the Royal Botanic Gardens, Kew, the scientists calculated that there are between 10 and 20 percent more undiscovered flowering plant species than previously estimated. The study was published in the journal "Proceedings of the Royal Society B."

Scientists are continually discovering plant species previously unknown to science. Among the more than 250 new species discovered or described by Kew scientists in the past year are massive flowering trees in the rainforests of Cameroon.

The tallest is the Berlinia korupensis, named by Dr. Barbara Mackinder, which stands 42 meters in height. A member of the pea family, the Berlinia bears beautiful white flowers with enormous pods that explode when ripe, propelling the seeds away from the mother tree.

Surveys of the Cameroon's Korup National Park show that this tree is extremely rare. "We found just 17 trees in our surveys," said Kew's Xander van der Burgt. "Even though Korup is protected, Berlinia korupensis is critically endangered due to human pressures on the park."

The assessment released today adds to the Sampled Red List Index for Plants, which analyzes a large sample of plant species that collectively represent of all the world's plants.

The Sampled Red List Index for Plants is part of the IUCN's authoritative Red List of Threatened Species, a worldwide effort to create a tool to monitor the changing status of the world's major groups of plants, fungi and animals.

"We cannot sit back and watch plant species disappear - plants are the basis of all life on Earth, providing clean air, water, food and fuel," Hopper said. "All animal and bird life depends on them and so do we. Having the tools and knowledge to turn around loss of biodiversity is now more important than ever and the Sampled Red List Index for Plants gives conservationists and scientists one such tool."

全文及圖片詳見:ENS報導