?The birds are arriving in the Arctic up to 13 days earlier than they used to. But at a cost: hunger.這些鳥比過去提前了13天到達(dá)北極,為此付出的代價(jià)是:饑餓。 撰文\播音:安妮·斯尼德(Annie Sneed) 翻譯:張朵兒
? Every spring, a bird called the barnacle goose migrates from the coast of the North Sea to the Russian Arctic, where it breeds. That’s a 3000-kilometer trip. Along the way, the geese usually take pit stops to rest and refuel. ?But the Arctic spring has been arriving earlier and earlier. 每年春天,一種名叫白頰黑雁的鳥會(huì)從北海沿岸遷徙到俄羅斯北部北極圈以內(nèi)的地區(qū),并在那里繁殖。這是一場(chǎng)長(zhǎng)達(dá)3000公里的旅程。一路上,它們通常會(huì)中途休息和補(bǔ)充能量。但是北極的春天來得越來越早了。
? So researchers analyzed six years of barnacle goose migratory tracking data. To try to figure out if these geese—and other species like it—can adapt their migration, to stay in sync with the changing seasons. 研究人員分析了白頰黑雁六年的遷徙追蹤數(shù)據(jù),試圖弄清楚這些鳥類及其他相似物種的遷徙是否與季節(jié)變化保持同步。
? ?“Then we used satellite images to see when snow was melting in the Arctic, and then we could relate the timing of the birds to the snow melt.” Bart Nolet, an ecologist at the University of Amsterdam. “我們使用衛(wèi)星圖像來觀察北極的雪什么時(shí)候融化,然后我們可以將鳥類的遷徙期與雪融化的時(shí)間聯(lián)系起來。”阿姆斯特丹大學(xué)的生態(tài)學(xué)家巴特?諾萊特(Bart Nolet)說。
? Nolet and his colleagues found that the geese did not leave their wintering grounds sooner to match the earlier Arctic spring. But they did speed up their trip—by skipping many of their usual stopovers. The birds arrived in the Arctic up to 13 days earlier than they used to. But at a cost. 諾萊特和他的同事們發(fā)現(xiàn),黑雁不會(huì)提前離開他們過冬地方,來配合北極的早春。但是他們確實(shí)會(huì)跳過許多以往的停留地點(diǎn)近而加快他們的行程。這些鳥比過去提前了13天到達(dá)北極,但這是有代價(jià)的。
? ?“So in a normal year, they start laying their eggs right after arrival. But now they spent more than a week foraging before they laid their eggs…. So in effect, they weren’t that much earlier than would have been the case. As a result, the chicks that hatch from the eggs in that early year, they survive much less than normal. Probably because they missed the food peak, which is a combination of very high quality in the grass, and enough grass around. And that food peak is around three weeks after snow melt, but now they were a few weeks later.” “在正常的一年中,他們?cè)诘诌_(dá)后會(huì)立即開始產(chǎn)卵。但是現(xiàn)在,他們?cè)诋a(chǎn)卵前花了一個(gè)多星期的時(shí)間覓食......?所以實(shí)際上,他們的產(chǎn)卵時(shí)間并沒有比往常早多少。因此,孵化出的幼鳥,存活率遠(yuǎn)低于正常水平??赡苁且?yàn)?/span>這樣孵化出的幼崽錯(cuò)過了草地面積充裕且草質(zhì)高的食物高峰期。食物高峰期約為雪融化后的三周,但現(xiàn)在孵化出的幼崽時(shí)已經(jīng)遲了食物高峰期幾周。”
? With devastating effects. 這將帶來毀滅性的影響。
? ?“We looked at the daily survival of the goslings... If you calculate it over the whole month, then it’s quite dramatic, they decrease from 20 percent to only 2 percent surviving. It basically means that not many goslings are surviving in such a year.” The study is in the journal Current Biology. [Thomas K. Lameris et al., Arctic Geese Tune Migration to a Warming Climate but Still Suffer from a Phenological Mismatch] “我們研究了小雁每日的生存情況......如果你按整個(gè)月計(jì)算,那么情況非常帶有戲劇性,小雁的存活率從20%減少到了只有2%。這意味著在這一年里沒有多少小雁存活下來。”這項(xiàng)研究發(fā)表在《當(dāng)代生物學(xué)?》雜志上。
? So why don’t the geese just leave their wintering grounds earlier? 那么大雁為什么不早點(diǎn)離開他們的越冬地呢?
? ?“When it’s an early spring in the Arctic, it’s not necessarily an early spring in the wintering area.?So the birds cannot use any cue that’s related to what’s early or late spring to leave.” “當(dāng)北極進(jìn)入早春時(shí),越冬地不一定也是早春。因此,鳥類無法得到任何與早春或晚春相關(guān)的提示信息。”
? But Nolet does think there’s some hope they might be able to adapt. “We know that the goslings learn their migration from their parents, so there’s a lot of learned behavior in it. So it may well be that in the course of time, some birds discover that they have to depart earlier from their wintering areas to be able to time their migration perfectly, and match it with the Arctic.” 但諾萊特仍然對(duì)鳥類的適應(yīng)抱有希望。“我們知道小雁從他們的父母那里學(xué)習(xí)遷徙,還包括更多的學(xué)習(xí)行為。因此,隨著時(shí)間的推移,有些鳥類會(huì)發(fā)現(xiàn)它們必須早早地離開它們的越冬地才能完美地完成遷徙,從而與北極的變化相適應(yīng)。”