如何与其他动物分享地球

如何与其他动物分享地球

Earth is a big place, but size isn't everything. The planet's richest ecosystems are in rapid decline, forcing us to acknowledge the elephant in the room: Elephants, along with countless other creatures worldwide, are running out of room.

地球是一个很大的地方，但大小并不是一切。地球上最丰富的生态系统正在迅速衰落，这迫使我们认识到一个显而易见而又被忽略的事实:大象，以及世界上无数其他生物，正在耗尽空间。

A young lion looks toward the Nairobi skyline from Nairobi National Park in Kenya. (Photo: Tony Karumba/AFP/Getty Images)

Like climate change, mass extinction is a global problem. It threatens wildlife all over the world, from iconic rhinos, lions and pandas to obscure amphibians, shellfish and songbirds. And while it will take lots of local efforts to save those animals, it will also take a bigger, more ambitious approach than we've used in the past.

与气候变化一样，大规模灭绝也是一个全球性问题。它威胁着世界各地的野生动物，从标志性的犀牛、狮子和熊猫，到鲜为人知的两栖动物、贝类和鸣禽。虽然拯救这些动物需要很多当地的努力，但它也将采取比我们过去使用的更好、更有野心的方法。

According to many scientists and conservationists, our best strategy is surprisingly simple — at least in theory. To avoid a catastrophic loss of biodiversity, we need to set aside half of Earth's surface area for wildlife. That might sound like a big sacrifice at first, but upon closer inspection, it's still an incredibly sweet deal for us: One species gets half the planet, and all other species must share the other half.

根据许多科学家和环保人士的说法，我们最好的策略出奇地简单——至少在理论上是这样。为了避免生物多样性的灾难性损失，我们需要留出地球表面一半的面积给野生动物。一开始，这听起来像是一个巨大的牺牲，但仔细观察，这对我们来说仍然是一个令人难以置信的甜蜜交易:一个物种得到了地球的一半，而所有其他物种必须分享另一半。

The Amazon rainforest spans 40% of South America and hosts one in 10 of Earth's known species. (Photo: Shutterstock)

Half an Earth is better than none

半个地球总比没有好

Today, protected areas cover about 15% of Earth's land area and 3% of its oceans, according to the U.N. Environment Program. Raising that to 50% would be no small feat, but it's not like we'd need to start from scratch. We would, however, need to move a little more quickly than we have so far.

根据联合国环境规划署(U.N. Environment Program)的数据，如今，保护区覆盖了地球陆地面积的15%，海洋面积的3%。将这一比例提高到50%将是一个不小的成就，但我们并不需要从零开始。然而，我们需要比目前更快地采取行动。

A gray heron wades through reeds at a 100-acre urban wetland in London. (Photo: Dan Kitwood/Getty Images)

Missing forests for trees

为树木而失去森林

About 60% of the U.S. Southeast was once longleaf pine forest, for example, which spanned 90 million acres from modern-day Virginia to Texas. After 300 years of land change for timber, agriculture and urban development, less than 3% of the region's signature ecosystem is left. A lot of biodiversity still persists in its remaining pockets — including up to 140 plant species per square kilometer — but large animals like Florida panthers and black bears are frequently killed by road traffic as they try to improvise their own makeshift wildlife corridors.

例如，美国东南部约60%的地区曾经是长叶松林，从现在的弗吉尼亚到德克萨斯州，这片松林占地9000万英亩。经过300年为木材、农业和城市发展而改变的土地，该地区标志性的生态系统只剩下不到3%。许多生物多样性仍然存在于其剩余的区域——包括每平方公里多达140种植物——但是像佛罗里达黑豹和黑熊这样的大型动物在试图临时搭建自己的野生动物走廊时经常被公路交通撞死。

A sign in Everglades National Park warns motorists to watch for Florida panthers. (Photo: Everglades NPS)

Because ecosystems are so interwoven, the loss of one species can start a horrible chain reaction. When the American chestnut tree was driven to near extinction 100 years ago by an invasive Asian fungus, Wilson notes, "seven moth species whose caterpillars depended on its vegetation vanished, and the last of the passenger pigeons plunged to extinction." Similarly, the modern decline of monarch butterflies is largely linked to the decline of milkweed, on which their larvae rely for food.

由于生态系统是如此的相互交织，一个物种的消失可能会引发可怕的连锁反应。威尔逊指出，100年前，一种入侵的亚洲真菌将美洲栗树逼到了濒临灭绝的境地，“七种依赖栗树生长的毛虫的蛾子消失了，最后一种信鸽也濒临灭绝。”同样，帝王蝶数量的减少在很大程度上与马利筋数量的减少有关，马利筋是帝王蝶幼虫的食物来源。

Even for urban-adapted birds, air pollution and climate change can pose grave threats. (Photo: Frederic Brown/Getty Images)

How the other half lives

另一半是如何生活的

Although we need to think bigger about habitat conservation, preserving tracts of wilderness is still a local struggle. If we set aside enough half-yards, half-towns, half-nations and half-regions for nature, Half-Earth should start to take care of itself.

尽管我们需要从更大的角度来考虑栖息地保护问题，但保护大片荒野仍然是一场地方性的斗争。如果我们留出足够的半码，半城镇，半民族和半地区的自然，半地球应该开始照顾自己。

Half-Earth, therefore, isn't so different from today's Earth. We're already doing many of the right things, as Wilson recently told the University of California-Berkeley's "Breakthroughs" magazine. We still have a few big biodiversity zones left, and others that could still recover. We just need to protect as many wilderness areas as we can, fill in gaps wherever possible and do no further harm.

因此，半地球与今天的地球并没有太大的不同。正如威尔逊最近对加州大学伯克利分校的《突破》杂志所说，我们已经在做许多正确的事情。我们仍然有一些大的生物多样性区域，其他的仍然可以恢复。我们只需要保护尽可能多的荒野地区，尽可能地填补空白，不再造成进一步的伤害。