氣候變暖讓灰熊棄葷從素改吃漿果

灰熊本是食肉動(dòng)物，但是現(xiàn)在阿拉斯加科迪亞克島的灰熊卻放棄了鮭魚(yú)而轉(zhuǎn)而以漿果為主食，變成了“素食者”，這是怎么回事呢?

Grizzly bears have stopped eating salmon in favour of elderberries after being forced to make a choice due to climate change. Warming temperatures meant that the berries are ripening earlier than usual, at exactly the same time as the freshwater streams on Alaska’s Kodiak Island are overflowing with sockeye salmon.

由于氣候變化的影響，灰熊被迫做出艱難抉擇，放棄鮭魚(yú)改吃接骨木果。溫暖的氣候使得漿果成熟期提前，與此同時(shí)，阿拉斯加科迪亞克島的淡水河流里也擠滿了紅鮭。

The island's brown bears typically feed first on salmon in early summer, followed by elderberries later in the season, in late August and September.

往年，島上的棕熊在夏初先吃了鮭魚(yú)，然后在八月末和九月吃接骨木果。

"What you have is a scrambling of the schedule," said William Deacy, a biologist at Oregon State University that studied the phenomenon.

研究這個(gè)現(xiàn)象的俄勒岡州立大學(xué)的生物學(xué)家威廉•迪西稱：“如今的生物成熟期十分混亂。”

"It's essentially like if breakfast and lunch were served at same time and then there is nothing to eat until dinner.

“這就好比早餐和午餐同時(shí)送上來(lái)，那么晚餐前就什么都沒(méi)得吃了。”

"You have to choose between breakfast and lunch because you can only eat so much at a time."

“你必須在早餐和午餐間做抉擇，因?yàn)槟阋淮沃荒艹阅敲炊唷?rdquo;

The study found that during the unusually warm summer of 2014, the bears, which would traditionally kill up to 75 percent of the salmon, were nowhere to be seen near the streams.

研究發(fā)現(xiàn)，在2014年，夏季異常溫暖，但流水旁卻不見(jiàn)灰熊的蹤影。照往常來(lái)說(shuō)，它們這時(shí)候可要吃掉高達(dá)75%的鮭魚(yú)。

Instead, they were in the hills busy munching on berries, which contain less protein and therefore take less energy to break down, causing them to gain weight more quickly.

但是，它們一反常態(tài)，跑到山上大吃漿果。漿果里面的蛋白質(zhì)含量低，消化分解所需能量少，因此它們長(zhǎng)胖的速度也加快了。

Biologists warned that changes caused by a warming planet were behind the bears' unusual behavior and could affect the entire ecosystem.

生物學(xué)家們警告稱，灰熊不尋常的行為背后反映的是全球變暖所帶來(lái)的變化，可能會(huì)影響整個(gè)生態(tài)系統(tǒng)。

The researchers found that the forests around the streams suffered because the bears’ fish carcasses were no longer there to enrich the soil.

研究人員發(fā)現(xiàn)，沒(méi)有灰熊吃剩的魚(yú)骸來(lái)給土壤增肥，河流周?chē)纳忠呀?jīng)受到了影響。

"Bears switched from eating salmon to elderberries, disrupting an ecological link that typically fertilizes terrestrial ecosystems and generates high mortality rates for salmon," the study said.

研究表明：“灰熊不吃鮭魚(yú)改吃接骨木果的行為不僅破壞了滋養(yǎng)陸地生態(tài)系統(tǒng)的生態(tài)鏈，還促成了鮭魚(yú)的高死亡率。”

On average, red elderberries are said to be ripening two and a half days earlier every decade.

據(jù)稱，平均每十年，紅接骨木果成熟的時(shí)間會(huì)提前兩天半。

If the pattern continues, they will regularly overlap with the salmon by 2070.

如果再這樣下去，到2070年，鮭魚(yú)和接骨木果的成熟期將會(huì)定期重合。

The study was published in the Proceedings of the National Academy of Sciences.

這項(xiàng)研究成果已在《美國(guó)科學(xué)院學(xué)報(bào)》上發(fā)表。