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Now listen to part of lecture on the topic you just read about.
现在来听一段关于你刚刚所读到的话题的演讲。
The cane toad won't be as easy to get rid of as the reading suggests.
海蟾蜍不像阅读中说的那样容易摆脱。
The measures proposed by the reading are likely either to be unsuccessful or to cause unwanted environmental damage.
阅读中所提出的方法可能不是不成功就是会带来不必要的环境损害。
First of all, a national fence probably won't stop the spread of the toad. That's because young toads and toad eggs are found in rivers and streams.
首先，一个国家性的围栏并不能阻挡海蟾蜍的传播。因为在河流和溪流里能找到幼蟾蜍和蟾蜍蛋。
No matter where the fence is located, at some point there will be rivers or streams flowing from one side to the other.
不论围栏放在哪里，在某个地方总有从一边流到另一边的河流和溪流。
These waterways will be able to carry the young toads and their eggs to the other side.
这些水道能把幼蟾蜍和蟾蜍蛋带到另一边。
Since it's only necessary for a few young toads or eggs to get through the fence in order to establish population on the other side, the fence is unlikely to be effective.
因为只有少部分的幼蟾蜍和蟾蜍蛋需要通过篱笆来在另一边生成种群，所以篱笆不可能有效果。
Secondly, a massive group of volunteers could have success trapping and destroying toads.
第二，一大群的志愿者也许能成功地捕获并摧毁蟾蜍。
But it's likely that these untrained volunteers would inadvertently destroy many of Australia's native frogs. Some of which are endangered.
但是，可能这些没有经过训练的志愿者会不小心地摧毁澳大利亚本地的青蛙，有些已经濒临绝种。
It's not always easy to tell the cane toad apart from native frogs especially when it's young.
要从本地青蛙中分辨出海蟾蜍是不容易的，尤其当它还小的时候。
Third, using the virus is a bad idea because it could have terrible consequences for cane toads in their original habitat in Central and South America.
第三，使用病毒是个坏主意，因为这可能会给在它们的原始栖息地中部和南部美洲的海蟾蜍带来可怕的影响。
You might be wondering how can a virus released in Australia cause harm in the Americas.
你也许会奇怪，在澳大利亚释放的病毒怎么能在美洲产生危害呢？
Well, Australian reptiles and amphibians are often transported to other continents by researchers or pet collectors for example.
好吧，澳大利亚的爬行动物和两栖动物经常被运到其他的大陆，比如被专家或者宠物收集者。
Once the animals infected by the virus reach Central and South America, the virus will attack the native cane toads and devastate their populations.
一旦被病毒感染的动物到达中部或者南部美洲，病毒便会攻击当地的海蟾蜍并且毁灭它们的种群。
That would be an ecological disaster because in the Americas cane toads are a native species and a vital part of the ecosystem.
那将会是一个生态灾难，因为在美洲，海蟾蜍是一个原生物种，是生态系统中至关重要的一部分。
So if they are eliminated, the whole ecosystem will suffer.
所以如果它们被消灭了，整个生态系统将遭殃。
