Sea Otters Help Save California's Wetlands

2024-02-08

00:00 / 00:00
复读宝 RABC v8.0beta 复读机按钮使用说明
播放/暂停
停止
播放时:倒退3秒/复读时:回退AB段
播放时:快进3秒/复读时:前进AB段
拖动:改变速度/点击:恢复正常速度1.0
拖动改变复读暂停时间
点击:复读最近5秒/拖动:改变复读次数
设置A点
设置B点
取消复读并清除AB点
播放一行
停止播放
后退一行
前进一行
复读一行
复读多行
变速复读一行
变速复读多行
LRC
TXT
大字
小字
滚动
全页
1
  • At one point, it was nearly impossible to see sea otters along the west coast of the United States.
  • 2
  • The animals were hunted nearly to extinction in the 1800s. People paid for their fur.
  • 3
  • At one point, only about 2,000 remained. Most lived in the waters off Alaska.
  • 4
  • But by the 1980s, the animals started to recover.
  • 5
  • Three programs helped increase their population in northern California.
  • 6
  • First, hunters were banned from killing the otters.
  • 7
  • Next, an environmental program restored the wetlands where the otters once lived.
  • 8
  • And finally, California's Monterey Bay Aquarium began to raise otters and release them into the wild.
  • 9
  • For about 40 years, the animals have been back in the seaside area called Elkhorn Slough.
  • 10
  • It is between Monterey and San Francisco.
  • 11
  • Brent Hughes is studying how the otters' return affected the environment.
  • 12
  • He is a marine ecologist at nearby Sonoma State University.
  • 13
  • He recently published a report in the science journal Nature.
  • 14
  • Hughes and his team looked at a wetland area called a tidal estuary.
  • 15
  • The researchers found that the otters perform a service that keeps the area from eroding -- or wearing away.
  • 16
  • Hughes said the otters feed on a destructive shellfish called the striped shore crab.
  • 17
  • The crabs dig into the mud and sand and bite the roots of a marsh grass known as pickleweed.
  • 18
  • Pickleweed holds the soil in place during coastal flooding.
  • 19
  • The holes the crabs make cause the area to look like "Swiss cheese," Hughes said.
  • 20
  • Swiss cheese is a kind of cheese with many holes.
  • 21
  • For the new study, researchers examined erosion rates dating back to the 1930s.
  • 22
  • The historical data help the researchers understand the effects of sea otters' return to the area.
  • 23
  • The researchers also set up fences that prevented the otters from entering certain areas for three years.
  • 24
  • In the fenced-off section of the estuary, the scientists say the soil eroded much more quickly.
  • 25
  • Hughes said the otters "don't completely reverse erosion but slow it down to natural levels."
  • 26
  • The otter study is one of several research projects that follow what happens to an area when a top predator returns after a long period of time.
  • 27
  • A famous past study looked at the return of gray wolves to Yellowstone National Park.
  • 28
  • The wolves hunted elk and moose that ate small trees along riverbanks.
  • 29
  • With fewer elk and moose, the trees started growing again and the riverbanks did not erode as quickly.
  • 30
  • Something similar happened when the otters returned.
  • 31
  • Johan Eklof is a Swedish marine biologist from Stockholm University who reviewed the study.
  • 32
  • Other studies, he noted, depended only on observation.
  • 33
  • But this new study leaves no doubt that the otters limit erosion.
  • 34
  • Other studies show that otters can be helpful for plants.
  • 35
  • One study said the otters eat sea creatures called urchins that feed on kelp.
  • 36
  • The return of the otters permitted the kelp to grow again.
  • 37
  • Brian Silliman is a coastal ecologist from Duke University in North Carolina. He co-wrote the new study.
  • 38
  • He described the otters as "amazing finders and eaters."
  • 39
  • I'm Dan Friedell.
  • 1
  • At one point, it was nearly impossible to see sea otters along the west coast of the United States.
  • 2
  • The animals were hunted nearly to extinction in the 1800s. People paid for their fur. At one point, only about 2,000 remained. Most lived in the waters off Alaska.
  • 3
  • But by the 1980s, the animals started to recover. Three programs helped increase their population in northern California. First, hunters were banned from killing the otters. Next, an environmental program restored the wetlands where the otters once lived. And finally, California's Monterey Bay Aquarium began to raise otters and release them into the wild.
  • 4
  • For about 40 years, the animals have been back in the seaside area called Elkhorn Slough. It is between Monterey and San Francisco.
  • 5
  • Brent Hughes is studying how the otters' return affected the environment. He is a marine ecologist at nearby Sonoma State University.
  • 6
  • He recently published a report in the science journal Nature. Hughes and his team looked at a wetland area called a tidal estuary. The researchers found that the otters perform a service that keeps the area from eroding -- or wearing away.
  • 7
  • Hughes said the otters feed on a destructive shellfish called the striped shore crab. The crabs dig into the mud and sand and bite the roots of a marsh grass known as pickleweed. Pickleweed holds the soil in place during coastal flooding.
  • 8
  • The holes the crabs make cause the area to look like "Swiss cheese," Hughes said. Swiss cheese is a kind of cheese with many holes.
  • 9
  • For the new study, researchers examined erosion rates dating back to the 1930s. The historical data help the researchers understand the effects of sea otters' return to the area.
  • 10
  • The researchers also set up fences that prevented the otters from entering certain areas for three years. In the fenced-off section of the estuary, the scientists say the soil eroded much more quickly.
  • 11
  • Hughes said the otters "don't completely reverse erosion but slow it down to natural levels."
  • 12
  • The otter study is one of several research projects that follow what happens to an area when a top predator returns after a long period of time.
  • 13
  • A famous past study looked at the return of gray wolves to Yellowstone National Park. The wolves hunted elk and moose that ate small trees along riverbanks. With fewer elk and moose, the trees started growing again and the riverbanks did not erode as quickly.
  • 14
  • Something similar happened when the otters returned.
  • 15
  • Johan Eklof is a Swedish marine biologist from Stockholm University who reviewed the study. Other studies, he noted, depended only on observation. But this new study leaves no doubt that the otters limit erosion.
  • 16
  • Other studies show that otters can be helpful for plants. One study said the otters eat sea creatures called urchins that feed on kelp. The return of the otters permitted the kelp to grow again.
  • 17
  • Brian Silliman is a coastal ecologist from Duke University in North Carolina. He co-wrote the new study. He described the otters as "amazing finders and eaters."
  • 18
  • I'm Dan Friedell.
  • 19
  • Dan Friedell adapted this story for Learning English based on a report by the Associated Press.
  • 20
  • ________________________________________________
  • 21
  • Words in This Story
  • 22
  • extinction -n. the state or situation that results when something (such as a plant or animal species) has died out completely
  • 23
  • affect -v. to produce an effect on something
  • 24
  • certain -n. a known place or area
  • 25
  • predator -n. an animal that lives by killing and eating other animals
  • 26
  • We want to hear from you. Have you ever seen a sea otter up close? What did you think?