國家地理:溫室效應(yīng)導(dǎo)致花種減少

In the Rocky Mountains of Central Colorado, the forces of nature create a landscape of alpine lakes, high-altitude ponds teeming with life and mountain meadows bursting with wild flowers. It is amidst these beautiful wildflower fields that one scientist has already found alarming evidence about the potential impact of global warming. John Hart, a professor of Environmental Science at the University of California, Berkley, runs an experiment to determine what would happen if the temperature was just three degrees warmer here year around, like the forecasted effect of global warming.
“That heating effect will induce dramatic effects on these subalpine meadows, causing loss of plant seed we especially value here, the flowering plants.”
John Hart has come here each summer since the 1970s, examining factors affecting life in this fragile ecosystem.
“This heating is actually quite subtle. We are not heating a lot. It’s only a few degrees, but it’s causing the flowering plants to produce fewer flowers and to grow less abundantly.”
His setup is relatively simple. Low-power electric heaters suspended above a mountain meadow heat the ground and the plant life beneath, three degrees warmer than the surrounding area. The heaters are automatically and precisely controlled, they have been on constantly, day and night, winter, spring, summer and fall since 1991. In his global warming experiment, he suspended heaters in a grid pattern to create heated plots, then unheated plots, back and forth, so he can judge the effects side by side. The difference, three degrees of separation makes in flowers and sagebrush, is easy to see.
“They suck juices out of the plant.”
In the unheated natural area, sagebrush is a source of moisture for an army of thirsty insects. They keep sagebrush under control.
“So they have little mouthpieces that can suck away at the nutrient.”
But just a few feet away, sagebrush under the heater grows far better with fewer bugs.
“...much more rapidly, we found that the heating is causing profuse growth of the sagebrush.”
While that’s good for the sagebrush; it’s not good for its plant neighbors. Flowers feel the effect too. In natural areas, flowers grow thick as they always do here, but a few feet away, where it’s three degrees warmer, flowers are not as abundant.
“The meadows, instead of looking lush and strewn with flowers, are now actually rather arid.”
If global warming, or long-term climate change, does increase the year-around temperature here just a few degrees, John Hart predicts, in decades to come, flowers could be crowded out by sagebrush.
“Global warming is more than just an ecological catastrophe; it would be a human catastrophe in all of its dimensions.”
參考中文翻譯：
科羅拉多州中部巍峨的高山上，自然的力量創(chuàng)造了一幅美麗的風(fēng)景畫，有著高山湖，充滿生命的高海拔池塘，長滿野花的高山草原。在這些美麗的野花中，一位科學(xué)家發(fā)現(xiàn)了全球氣候變暖的潛在影響的有力證據(jù)。John Hart是加利福尼亞大學(xué)環(huán)境科學(xué)的教授。他組織了一個(gè)實(shí)驗(yàn)，觀察如果這里一年之內(nèi)氣溫升高3度會(huì)有什么情況發(fā)生，就好象全球氣候變暖的預(yù)報(bào)。
“熱效應(yīng)會(huì)對(duì)這些亞高山帶的草原產(chǎn)生劇烈的影響，造成我們非常珍惜的開花類植物的減少。”
從上世紀(jì)70年代開始，John Hart每年夏天都會(huì)來這里，檢查影響脆弱的生態(tài)系統(tǒng)的因素。
“加熱量其實(shí)很微小，我們沒有加熱很多。僅僅幾度的變化，就會(huì)導(dǎo)致開花類作物開花量減少，不像以前那樣豐富。”
他的設(shè)備相對(duì)來說很簡單。低功率的電加熱器懸掛在高山草原上給地面和下面的植物加熱，比周圍環(huán)境溫度高3度。加熱器是自動(dòng)化的，溫控非常精確。從1991年開始，加熱器就春夏秋冬日日夜夜的懸掛在那里。在他的全球變暖實(shí)驗(yàn)中，他按照格子狀懸掛加熱器，以組成加熱區(qū)和非加熱區(qū)，來來回回，這樣來判款交互影響。3度的差別給花和山艾樹造成的差別一目了然。
“他們從植物里吸取汁液。”
在沒有加熱的自然區(qū)域，山艾樹是很多昆蟲的水源。他們使山艾樹的數(shù)目受到控制。
“他們并沒有吸取里面的營養(yǎng)。”
但是就在幾英尺之外，收到加熱的山艾樹生長狀況好很多，蟲子很少。
“我們發(fā)現(xiàn)，加熱使山艾樹生長速度過快。”
雖然這樣對(duì)山艾樹比較好，但是對(duì)鄰近的植物造成威脅?；ㄒ哺惺艿搅擞绊?。在自然區(qū)域，花張的比較厚密，溫度高3度的幾英尺之外，花開的就沒有那么繁盛。
“草地沒有看上去蒼翠繁茂，鮮花盛開，反而變成了不毛之地。”
John Hart預(yù)測，如果全球變暖或者長期的氣候變化導(dǎo)致這里的全年平均氣溫升高幾度，未來的幾十年之內(nèi)，鮮花會(huì)被山艾樹吞噬。
“全球變暖并不只是生態(tài)災(zāi)難，對(duì)人類來說，也是一個(gè)巨大的災(zāi)難。”