七个世界，一个星球（2019）

Seven Worlds, One Planet S01E03

Part 3 Nov. 26, 2024, 8:46 p.m.

依赖于这片清澈的水源
relies on these waters remaining clear.
但是今天南美河流的未来充满了变数
But today, the future of South America's rivers has become uncertain.
人类生活依赖于河流随着人口的增长人们逐渐将河流
As the human population has grown, people have become more and more reliant
视为现代生活不可或缺的基础
on its rivers for one of the essentials of modern life.
例如电力
Power.
现在南美能源的三分之二来自水力发电
Two-thirds of South America's energy now comes from hydroelectricity.
南美洲对水力的依赖程度远超世界其它地区
No other region on Earth is so dependent upon it.
倘若水坝管理不当可能会导致更为严重的问题
But the way these dams are managed can cause problems farther downriver.
这里是伊瓜苏瀑布
These are the Iguazu Falls.
如果上游的水坝开闸放水伊瓜苏瀑布的规模就会扩大一倍
If the dams upriver suddenly release their excess, Iguazu can double in size.
这会给生活在附近的动物带来极大的灾难
And that can cause major problems for animals that live here.
这是大黑雨燕
These are great dusky swifts.
它们飞到汹涌澎湃的洪流附近
They fly alarmingly close to the thundering torrent...
然后就消失了
...and then vanish.
它们能够神奇地穿越水幕
Miraculously, they're able to fly right through the curtain of water.
它们之所以铤而走险是因为它们的筑巢地就位于瀑布水幕后的岩壁上
And they do so because they've built their nests behind the thundering curtain.
像卡拉卡拉鹰这样的天敌不能跟随它们穿越瀑布
Their enemies - falcons, like this caracara - can't follow them.
因此这群雨燕的雏鸟是安全的
So the swift chicks are safe.
但是现在人类活动为雨燕带来了新的困难
But now humans have created new problems for the swifts.
就在这群雏鸟学习飞行时
Just as some of the chicks are starting to fly,
大坝为了避免水位过高而开闸放水
the spill over the dams is released in full force.
激增的水量迫使雨燕父母放弃了最后的栖息地
As the torrent grows, parents give up on the last perches.
雏鸟孤零零地留在了后面
Now the chicks are alone.
它们还没有长出像父母那样的防水羽绒
But they don't yet have their parents' waterproof feathers.
每年突如其来的洪流都会带走不少雏鸟的性命
Every year, the sudden surges of water sweep some to their death.
除了滚滚洪水这群雏鸟还没有见过外面的世界
The chicks have never seen the world beyond the falling waters.
除非它们找到飞出瀑布的办法否则只有死路一条
Unless they can find a way through, they will not survive.
不可思议的是在本能的驱使下
Amazingly, driven by blind instinct,
一些雏鸟确实能够逃出去
chicks do manage to power their way through.
这群非凡的鸟儿在绝境之中迎来了一线生机
These remarkable birds have colonised a niche in which few can survive.
然而它们的未来乃至南美洲所有野生动植物的未来
Yet their future, and that of all wildlife in South America,
需要我们在这片富饶而多样的土地上小心翼翼地权衡
will depend on us striking a balance between the needs of humans and animals,
人类与动物不同的需求
on the richest and most diverse continent on Earth.
下集预告
Next time...
一个在恐龙时代
...a continent marooned
被放逐的大洲
during the time of the dinosaurs,
而随之飘流者
where the castaways...
样貌奇特与众不同
...are like nothing else on Earth.
澳洲
Australia.