【媒库文选】大象和猴子正以人类做不到的方式对抗气候变化

2019-09-04 14:40   参考消息网  

Elephants and Monkeys Are Fighting Climate Change in Ways Humans Can't

大象和猴子正以人类做不到的方式对抗气候变化

Marlene Cimons 马琳·西蒙斯

Mother Nature has it figured out. She's designed a master scheme that connects plants and animals, all working in concert to keep every living thing in balance. Imagine a stack of dominoes—knock down one of them, and the rest will tumble. The same can happen in nature.

This is especially evident in places like central Africa and in South American tropical rainforests where certain animals—from the world's largest to its smallest—help keep trees safe and healthy, which is critical as trees absorb vast amounts of planet-warming carbon pollution.

Recent research warns that losing the creatures that nurture trees puts forests in danger. This, by extension,is helping to accelerate dangerous climate change.

In central Africa, for example, elephants eat fast-growing trees, making room for those that grow more slowly. The slow-growing trees—with their very dense wood—store more carbon than their thinner, faster-developing counterparts. Without elephants, more carbon would accumulate in the atmosphere, worsening climate change, according to a new study that used computer models to project what could happen if elephant populations continue to dwindle or become extinct.

“Africa may once have contained 10 million elephants from the Mediterranean to the Cape, in every habitat except extreme desert. In 1970, there may have been a million left. By the end of the 1980s, there were half that number, mostly killed for the ivory trade,”said Stephen Blake, assistant professor of biology at St. Louis University, and author of the study, which appears in the journal Nature Geoscience.

By killing elephants, poachers rob slow-growing trees of their guardian. They also slow the growth of new trees. Elephants blaze trails and disperse seeds as they forage.“Elephants are basically the gardeners of the forest,”Blake said.“They disperse over 100 species of seeds, and disperse more of them over longer distances that other dispersers.”

Similarly, some of the world's littlest creatures also help replenish forests, although they don't face the grave risks that elephants encounter. Tiny tamarins that live in Peruvian rainforests eat fruits from trees, then poop out the undigested seeds in degraded former pastures—land cleared by humans for grazing water buffalo—effectively planting trees.

Scientists showed that two types of these squirrel-sized monkeys—moustached and black-fronted tamarins—are seeding new forests. This is vital because—like the forests of central Africa—tropical rainforests also store carbon, and are home to a vast number of plants and animals.

The scientists tracked seeds from the animals' feces deposited in the new forest and identified eight different plant species found in the main rainforest.“Tamarins can play a role for the natural regeneration of disturbed areas,”said Eckhard W. Heymann, a scientist at the German Primate Center.

However, their contribution, while important, usually isn't enough to regenerate large tracts.“So it is better to protect the forests—which also protects the animals living there—than to rely on the services [of tamarins].”Moreover, climate change may be altering the plants that tamarins eat, changing when they produce leaves, flowers, and fruits. This could limit tamarins' ability to seed new forests.

Blake, who has spent nearly 20 years in Africa working in elephant research and conservation, laments their fate, describing them as “a complex society of intelligent, caring, emotional animals who respect their grandmothers and mourn their dead,” and condemns those who neglect their duty to save them.

“We will go to Mars—there is no doubt—humans are too smart not to,”he said.“Yet we do not have the wisdom to protect elephants and their forest environment that do so much for our physical, spiritual, and emotional well-being.”

大自然自有办法。它设计了一个将植物和动物联系起来的卓越方案,让它们协力保持所有生物的平衡。试想有一列多米诺骨牌,推倒其中一块,剩下的将会倒下。同样的情况在自然界也会发生。

这在非洲中部和南美热带雨林等地尤其明显,在那些地方,某些动物帮助保持树木的安全和健康,其中既有全世界最大的动物,也有最小的动物。这一点至关重要,因为树木吸收大量能导致地球变暖的碳污染。

最近的研究警告称,失去那些能养护树木的动物会令森林陷于危险。延伸开来说,这会加速危险的气候变化。

例如,在非洲中部,大象会吃生长迅速的树,从而为生长较慢的树留出空间。那些生长缓慢的树木的木材密度很高,相较于木材密度更小、生长更快的树木,它们能储存更多的碳。一项新研究利用了计算机模型来预测如果大象继续减少或灭绝的话可能会发生什么,该研究显示,如果没有大象,大气中会累积更多的碳,从而加剧气候变化。

圣路易斯大学的生物学助理教授、《自然·地球科学》月刊上这份研究报告的作者斯蒂芬·布莱克说:“从地中海到好望角,非洲可能曾有1000万头大象,它们分布在除条件极其恶劣的沙漠之外的每处栖息地。1970年可能还有100万头。到上世纪80年代末,它们的数量又减少了一半,主要因为象牙贸易被杀。”

偷猎者杀死大象会令生长缓慢的树木失去守护者。他们还令新树生长放慢。大象觅食时会开辟小径并传播种子。布莱克说:“从根本上说,大象是森林的园丁。它们能传播100多种种子,并且与其他种子传播者相比,它们能将更多的种子传播到更远的地方。”

同样,一些世界上最小的动物也能帮忙植树造林,尽管它们并未面临大象遭遇的那些严重风险。生活在秘鲁热带雨林的小柽柳猴会吃树上的果子,然后将未消化的种子随粪便排到曾为牧场、后来退化的土地,从而在其上种植树木。人类为了养水牛而清理了那些土地。

科学家表明,这些松鼠大小的猴子中有两种——长须柽柳猴和黑额柽柳猴正在播种新的森林。这至关重要,因为与非洲中部的森林一样,热带雨林也能储存碳,并且是大量动植物的栖息地。

科学家们对这些动物遗留在新森林的粪便中的种子进行了追踪,发现了存在于最大雨林中的八种植物。德国灵长类动物研究中心的科学家埃克哈德·海曼说:“柽柳猴可以对受干扰区域的自然再生发挥一定作用。”

然而,它们的贡献虽然重要,但通常不足以再造大片树林。“所以,与其依靠(柽柳猴的)帮助,不如保护森林,这也能保护生活在那里的动物。”此外,气候变化可能正改变柽柳猴所吃的植物,改变它们长叶、开花和结果的时间。这可能会限制柽柳猴播种新林的能力。

在非洲从事大象研究和保护工作近20年的布莱克对它们的命运表示痛惜,称它们是“一个由有智慧、有爱心、有情感的动物组成的复杂社群,它们会尊重祖母并哀悼死去的同类”,他谴责那些忽视了拯救大象责任的人。

他说:“我们会登上火星,这一点毫无疑问,人类太聪明了,不会做不到。但我们没有足够的智慧来保护大象及其森林环境,它们对我们的身体、精神和情感健康大有助益。”(李莎译自美国《大众科学》月刊网站8月13日文章)

广告

扫描二维码 便捷订阅《参考消息》