科学美国人60秒 SSS 恢复河流生态系统只需注水（在线收听）

This is Scientific American's 60-second Science, I'm Jason Goldman.

这里是科学美国人——60秒科学系列，我是苏杰森·戈德曼。

In the 1800s, many rivers in the American West were diverted for irrigation or dammed for generating electricity.

在19世纪，美国西部的许多河流改道用于灌溉或筑坝发电。

So rapidly expanding cities began tapping into groundwater. Add climate change into the mix, and you can see how an already arid desert can become even more parched.

因此，快速扩张的城市开始开采地下水。再加上气候变化，你就会发现原本就干旱的沙漠变得更加干旱。

The banks of the Santa Cruz River in southeastern Arizona were described in 1855 as “covered with poplars and willows, ash trees and plantains, oaks and walnut trees.” But a century later the river was gone.

1855年，亚利桑那州东南部的圣克鲁斯河的河岸被描述为“覆盖着杨树、柳树、白蜡树、大蕉树、橡树和核桃树。” 但一个世纪后，这条河消失了。

“But It was the original river of Tucson and the reason the city is here.”

“不过这是图森的原始河流，也是这座城市存在的原因。”

Ecologist Michael Bogan from the University of Arizona.

来自亚利桑那大学的生态学家迈克尔·博根。

Seventy years after it ran dry, the city of Tucson decided to release treated wastewater back into the riverbed—around 2.8 million gallons each day.

在它干涸70年后，图森市决定将处理过的废水排放回河床——大约每天280万加仑。

Bogan went to participate in the festivities when the valves were opened in June 2019.

2019年6月阀门打开时，博根参加了庆祝活动。

“Everybody was splashing around in the water, excited to see water back in the river. And what I immediately got sidetracked with was the number of dragonflies that I was seeing.”

“每个人都在水里戏水，看到水又流回到河里，都很兴奋。我马上就转移了注意力，因为我看到了蜻蜓的数量。”

Within a few hours, Bogan counted seven different species of dragonflies. He even saw dragonflies and damselflies mating and laying eggs—at a river that had not existed earlier that day.

几小时内，博根数出了七种不同种类的蜻蜓。他甚至看到蜻蜓和豆娘河流里交配和产卵，这条河流当天早些时候还不存在。

“And so I was like, ‘Oh my gosh, I need to study this. This is so cool, that these species are coming back so fast.’”

“所以我就想，‘哦，我的天哪，我需要研究这个。 这太酷了，这些物种回归得如此之快。’”

Just three months later, the Bogan’s team had documented roughly the same abundance and diversity of dragonflies that they’d seen in other parts of the river that have been flowing for years.

仅仅三个月后，博根的团队就记录了蜻蜓的数量和多样性，与他们在河流其他地区看到的数量和多样性大致相同。

Also abundant were mayflies and caddis flies. These invertebrates are indicators of a healthy aquatic ecosystem.

也有大量的蜉蝣和石蛾。这些无脊椎动物是健康水生生态系统的标志。

The results are published in the journal PeerJ.

研究结果发表在PeerJ杂志上。

“Most important is: just add water to these ecosystems. The species will find a way to get back there if you just put water back into these systems that we’ve dried up.

“最重要的是：只需为这些生态系统加水。如果你把水放回我们已经干涸的这些系统中，这些物种就会找到回到那里的方法。

The longer you can put water, and the more water you can put in, that’s great for creating a more diverse habitat and a greater abundance of species.

你放水的时间越长，可以流入的水就越多，这对于创造一个更多样化的栖息地和更丰富的物种是很好的。

But really, the simple answer is: just add water; that’s all we have to do to restore a lot of species.”

但实际上，简单的答案是:只需要加水; 这就是我们恢复许多物种所要做的一切。”

Still, this is a manufactured ecosystem. It’s not as if this artificially charged river is identical to the natural one that existed a century ago.

尽管如此，这是一个人造的生态系统。这条人工充电的河流与一个世纪前存在的自然河流并不相同。

“We like to call them managed ecosystems.

“我们喜欢称它们为受管理的生态系统。

Because they are...they do have a lot of natural aspects, these species are coming in there on their own. But they rely on, in this case, the City of Tucson and Tucson Water for releasing that water.

因为它们,它们确实有很多自然方面的原因，这些物种是自己进来的。但在这种情况下，他们依靠图森市和图森水公司来释放这些水。

Without the city doing that, they would have nothing.”

如果没有城市这样做，他们将一无所有。”

Bogan calls on urban planners and city officials to collaborate with ecologists and biologists to maximize the beneficial effects of biodiversity while still achieving the goals of urban development.

博根呼吁城市规划者和城市官员与生态学家和生物学家合作，在实现城市发展目标的同时，最大限度地发挥生物多样性的有益影响。

Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

谢谢大家收听科学美国人——60秒科学。我是苏杰森·戈德曼。