新型真菌隨人類行為擴散 全球蜜蜂持續消失 | 台灣環境資訊協會-環境資訊中心

新型真菌隨人類行為擴散 全球蜜蜂持續消失

建立於 2011/03/15
摘譯自2011年3月10號ENS肯亞報導;陳巾眉編譯;蔡麗伶審校

美國科學家發現一種真菌會攻擊瑪諾拉蟎。蜜蜂背上有一隻蟎。圖片來自:Steven Ausmus / USDA。聯合國在10日發表的新報告中提出警訊,若人類再不改變行為模式,蜜蜂數量持續減少,造成全球大部分糧食作物缺乏授粉者的災難將會持續。引起蜜蜂族群減少的原因多達十多項,包括開花植物消失、廣泛使用損害記憶力的殺蟲劑、空氣汙染和氣候變遷等因素。

報告指出,對蜜蜂以及其他傳播花粉昆蟲造成致命威脅的新型真菌病原體正全面蔓延,因為全球化以及國際貿易迅速成長,使得真菌病原體得以傳播到世界各地。

「供應世界上90%糧食的100種作物,其中70種是藉由蜜蜂傳授花粉。」聯合國環境規劃署負責人阿史坦納(Achim Steiner)指出。「人類如何發揮人道管理自然資源,包括傳授花粉的生物,將決定我們21世紀的共同未來」。

若缺乏進一步的的保育,蜜蜂賴以維生的兩萬種開花植物將在十年內消失。一項英國與荷蘭的共同研究發現,從1980年代起,薄荷、碗豆和多年生的主要野花族群數量已經減少70%。

越來越廣泛施用農藥對蜜蜂具有危害性,造成免疫系統功能減弱。研究顯示,在數種殺蟲劑和殺菌劑共同作用下,對蜜蜂的毒害性提高了一千倍。

此兩種藥劑也會影響蜜蜂的飛行方向感、記憶力與大腦代謝活動,農藥也可能會除掉蜜蜂和一些授粉昆蟲幼蟲的蜜源植物。

空氣汙染也會干擾蜜蜂找到蜜源的能力,空氣汙染使得植物傳遞出氣味分子的距離,在19世紀時可達800公尺,如今只能傳遞不到200公尺。

電力輸送網的電磁波也有可能改變蜜蜂的行為,因為蜜蜂腹部具有小型的含鉛晶體。

其他影響因素包括寄生蟲和蟎類,像是瑪諾拉蟎吸食蜜蜂體液為生,蜂巢小甲蟲會破壞儲存蜂蜜和花粉的蜂巢。原本這類影響只發生在撒哈拉沙漠以南,現在已經擴及到北美洲和澳洲,預計將會蔓延至歐洲。

中上方為非洲化蜜蜂。圖片來自:Scott Bauer / USDA。蜜蜂也會受到外來種競爭影響,像是美國的非洲化蜜蜂(Africanized bee, 人為造成歐洲蜂和非洲蜂的雜交種)以及亞洲大黃蜂會攻擊並吃掉歐洲蜂。

如果不解決造成廣泛影響的氣候變遷,將加劇各種層面的影響。像是改變植物的開花週期以及降雨模式,進而影響蜜源供應的質量。

「人類以為21世紀的科技能夠戰勝自然力量,蜜蜂減量的問題突顯了地球上70億人口深深依賴自然資源。」施泰納呼籲世人重視大自然所提供相當於數萬億美元的資源,如蜜蜂產蜜授粉的各種經濟產值。

第20屆地球高峰會議即將在2012年於巴西里約舉行(紀念里約高峰會滿20周年),史泰納呼籲世人重新投入並重視自然提供的寶貴資源,「像是替作物傳授花粉的蜜蜂」。

Bees Feel the Stings of a Dozen Deadly Things
NAIROBI, Kenya, March 10, 2011 (ENS)

The disastrous decline in bees that pollinate most of the world's food crops will continue unless humans profoundly change their ways, warns a United Nations report released today. More than a dozen factors are linked to the worldwide loss of bees, from the disappearance of flowering plants and the use of memory-damaging insecticides to the global spread of pests, air pollution and climate change.

New kinds of virulent fungal pathogens that can be deadly to bees and other pollinators are now showing up worldwide, migrating from one region to another due to shipments linked to globalization and rapidly growing international trade, the report finds.

"Of the 100 crop species that provide 90 percent of the world's food, over 70 are pollinated by bees," said UN Environment Programme Executive Director Achim Steiner today. "The way humanity manages or mismanages its nature-based assets, including pollinators, will in part define our collective future in the 21st century."

Some 20,000 flowering plant species upon which many bee species depend for food could be lost over the coming decades without greater conservation efforts. An Anglo-Dutch study has found that since the 1980s, there has been a 70 percent drop in key wildflowers among them the mint, pea and perennial herb families.

Meanwhile the increasing use of chemicals in agriculture is being found to damage bees, weakening their immune systems, with laboratory studies showing that some insecticides and fungicides can act together to be 1,000 times more toxic to bees.

They can also affect the sense of direction, memory and brain metabolism, and herbicides and pesticides may reduce the availability of plants bees need for food and for the larval stages of some pollinators.

Air pollution, too, may be interfering with the ability of bees to find flowering plants and thus food, with scents that could travel over 800 meters in the 1800s now reaching less than 200 meters from a plant.

Electromagnetic fields from sources such as power lines might also be changing the behavior of bees who are sensitive as they have small abdominal crystals that contain lead.

Another factor concerns parasites and pests, such as the Varroa mite which feeds on bee fluids, and the small hive beetle, which damages honeycombs, stored honey and pollen. Endemic to sub-Saharan Africa, it has spread to North America and Australia and is expected to reach Europe.

Bees may also be suffering from competition by alien species such as the Africanized bee in the United States and the Asian hornet which feed on European honey bees.

Looming over all this is climate change which, left unaddressed, may aggravate the situation in various ways, including by changing the flowering times of plants and shifting rainfall patterns, in turn affecting the quality and quantity of nectar supplies.

"Human beings have fabricated the illusion that in the 21st century they have the technological prowess to be independent of nature. Bees underline the reality that we are more, not less, dependent on nature's services in a world of close to seven billion people," Steiner said, calling on the world to factor in the often invisible multi-trillion dollar services provided by nature.

As the world prepares for Rio+20, the meeting in Rio de Janeiro, Brazil, next year marking the 20th anniversary of the Rio Earth Summit, Steiner called for investment and re-investment in nature-based services, "including pollination from insects such as bees."

全文及圖片詳見:ENS報導

※ 本文與合作刊登