澳洲特有生物 將面臨「不會停止」的氣候風險 | 環境資訊中心

澳洲特有生物 將面臨「不會停止」的氣候風險

2012年09月24日
摘譯自2012年9月19日ENS澳洲,雪梨報導;沈瑞筠編譯;蔡麗伶審校

澳洲維多利亞的桉樹林(照片由Fir0002/Flagstaffotos提供)澳洲國家科學機構發現,氣候變遷對澳洲特有的植物、動物及生態系的衝擊將導致物種滅絕及生態系服務喪失,敦促生物多樣性保育工作必須思考新的方向。

本研究由澳洲科學與工業研究組織(CSIRO)進行,他們模擬整個澳洲陸塊並對佔澳洲近80%的四個主要生物群系進行精密生態分析。

研究主持人Michael Dunlop博士表示,「到2030年時,氣候變遷會開始改變澳洲自然地景;到了2070年,生態的衝擊將是非常顯著及廣泛的。我們環境中現存的動植物將會消失,我們的孫子輩將會看到與我們目前所見完全不同的地景。」

CSIRO的研究人員分析四個主要生物群系詳細的氣候變化影響及適應機制,這四個生物群系分別是:澳洲乾燥區的丘陵草原、熱帶莽原草地及林地、溫帶草原及森林、及主要是開闊的桉樹林的南澳硬葉森林。

這項研究呈現:當對受威脅物種的管理及停止生物群系的改變越來越困難時,澳洲公眾及科學家們需要重新思考保護生物多樣性的意涵,

Dunlop博士表明,「比起試圖阻止生態變遷,我們更需要提供給多樣性最大的機會來適應變遷的環境。」

http://farm9.staticflickr.com/8448/7821836014_44e3e448ab_m.jpg澳洲擁有一百萬種原生生物,超過80%的開花植物、哺乳動物、爬蟲類或是蛙類、多數的淡水魚及幾乎一半的鳥類為澳洲特有的物種

在棲地改變、過度開發、污染、外來種入侵及氣候變遷的壓力下,澳洲的生物多樣性已急遽的下降,下降的速率可能是全世界最快速的。

澳洲在全世界有最糟的哺乳動物滅絕紀錄:在過去200百年間共有27種哺乳動物滅絕。

此外,超過1500種哺乳動物、鳥類、爬蟲類、兩棲動物及植物名列聯邦法律的瀕絕名單中,澳洲政府也確認出3000個瀕臨滅絕的生態系。

Dunlop指出,氣候變遷將會加強現存對生物多樣性的威脅:如棲地清除、抽取水或是外來種問題。

未來氣候變遷對農業、水資源供給及電力供應所產生的影響,都將施壓於物種及生態系上。Dunlop認為,「這些外在的其他威脅會降低原生物種及生態系因應氣候變遷的能力。」

澳洲新南威爾士省Callala灣的深紅玫瑰鸚鵡。目前這種鸚鵡已不再面臨瀕臨滅絕的處境。(照片由網友Wardie44B拍攝)研究人員表示,在氣候變遷議題浮出檯面前,過去多數的保育目標著重於生物多樣性保存,或是恢復一些退化地區至舊觀、或在特定範圍內維持現況。然而,氣候變遷將「對許多物種(無論是遺傳、豐富度及分佈的角度)或是生態系統的組成、結構與功能,都會啟動持續及無法阻擋的改變」。

這份研究表示,雖然這些變遷中的變化「基本上是無法阻擋的」,在特定的情況下,妥善的管理可能會產生一些影響、降低部分損失。Dunlop認為,「我們需要改變引導管理政策的公眾期望、政策方針及科學研究。可適應大尺度生態變化的靈活策略也將是必須的;等到生態改變明顯且普遍時再來因應就將太遲了。」

本研究發現,在氣候變遷影響下,國家保育系統將持續成為有效的保育工具,但私人土地的棲地保留將對物種及生態系適應扮演越來越重要的角色。

根據這份CSIRO的報告,「就澳洲生物多樣性而言,火本身並非一項威脅;但變動的火災模式似乎將成為生態改變的趨動力。在澳洲多數地區,乾旱將導致火災季節的延長且天氣型態孕育出可產生強烈火災的環境。」

本研究由澳洲政府永續環境水及族群部門(Department of Sustainability, Environment, Water, Population and Communities)、氣候變遷及能源效率部門(Department of Climate Change and Energy Efficiency)及澳洲科學與工業研究組織氣候適應旗艦計畫(CSIRO Climate Adaptation Flagship)贊助。

Australia’s Unique Species Face ‘Unstoppable’ Climate Danger
SYDNEY, Australia, September 19, 2012 (ENS)

The impact of climate change on Australia’s unique plants, animals and ecosystems will cause extinctions and lost ecosystem services and require new ways of thinking about biodiversity conservation, finds Australia’s national science agency.

Conducted by the Commonwealth Scientific and Industrial Research Organization, CSIRO, the study modeled 100 percent of Australia’s land mass and did detailed ecological analyses of four priority biomes, covering around 80 percent of Australia.

“Climate change is likely to start to transform some of Australia’s natural landscapes by 2030,” said lead researcher Dr. Michael Dunlop. “By 2070, the ecological impacts are likely to be very significant and widespread.”

“Many of the environments our plants and animals currently exist in will disappear from the continent,”  he said. “Our grandchildren are likely to experience landscapes that are very different to the ones we have known.”

The CSIRO researchers analyzed in detail climate impacts and adaptation options in four biomes: hummock grasslands of the arid interior of Australia; tropical savanna woodlands and grasslands; temperate grasslands and grassy woodlands; and southeastern Australia’s sclerophyll forests, which are open eucalypt woodlands.

The study suggests the Australian community and scientists need to start a rethink of what it means to conserve biodiversity, as managing threatened species and stopping ecological change becomes increasingly difficult.

“We need to give biodiversity the greatest opportunity to adapt naturally in a changing and variable environment rather than trying to prevent ecological change,” Dr. Dunlop said.

Australia contains one million different native species. More than 80 percent of the country’s flowering plants, mammals, reptiles and frogs are unique to Australia, along with most of its freshwater fish and almost half of its birds.

But under pressure from habitat change, overexploitation, pollution, invasive alien species and climate change, Australia’s biodiversity is already in steep decline, possibly faster than anywhere else in the world.

Australia has the worst mammal extinction record in the world – 27 mammals have become extinct in the last 200 years.

In addition, more than 1,500 mammals, birds, reptiles, amphibians and plants are listed as threatened with extinction under federal legislation. The Australian government also has identified 3,000 ecosystems facing extinction.

Dr. Dunlop said climate change will magnify existing threats to biodiversity, such as habitat clearing, water extraction and invasive species.

Future climate-driven changes in agriculture, water supply and electricity supply, could add to the pressure on species and ecosystems.

“These other threats have reduced the ability of native species and ecosystems to cope with the impacts of climate change,” Dr. Dunlop said.

Before concerns about climate change, most conservation objectives were focused on preserving biodiversity as it is, or restoring it to some prior condition from a current degraded state, or at best allowing some fluctuation within defined bounds, the study says.

However, the study finds, climate change will “drive continual and directional changes in the genetics, abundance and distribution of many species and in the composition, structure and function of ecosystems.”

Although most of these changes will be “essentially unstoppable,” the study says, in some situations management may be able to have some influence on how the changes unfold and may be able to reduce some of the losses.

“This could need new expectations from the community, possibly new directions in conservation policy, and new science to guide management,” Dr. Dunlop said.

“To be effective we also need flexible strategies that can be implemented well ahead of the large-scale ecological change. It will probably be too late to respond once the ecological change is clearly apparent and widespread,” he said.

The study found the National Reserve System will continue to be an effective conservation tool under climate change, but conserving habitat on private land will be increasingly important to help species and ecosystems adapt.

“While fire per se is not a threat to most Australian biodiversity, altered fire regimes are likely to be a significant driver of ecological change and a potentially driver of additional human impact. Drying is likely to lead to longer fire seasons and more weather capable of supporting intense fires across much of Australia,” according to the CSIRO report.

The study was funded by the Australian Government Department of Sustainability, Environment, Water, Population and Communities, the Department of Climate Change and Energy Efficiency and the CSIRO Climate Adaptation Flagship.

※ 全文及圖片詳見:ENS