PART 4

You now have one minute to check your answers to part four.

现在你有一分钟时间检查本部分的答案。

You will hear part of an ecology lecture about invasive species of plants and animals.

你将听到一段关于入侵植物和动物的生态学讲座的部分内容。

First, you have some time to look at questions 31 to 40.

首先，你有一些时间来查看问题 31 到 40。

Today I'm going to talk about invasive species.

今天我要谈谈入侵物种。

Let me start by saying what an invasive species is and what it's not.

让我先说说什么是入侵物种以及它不是什么。

Invasive species are any animal or plant that is introduced into an environment by humans, and which is then harmful to that environment.

入侵物种是任何由人类引入到一个环境中的动物或植物，而这些物种对这个环境是有害的。

It's important to be clear that not all introduced species are invasive.

重要的是要明确，不是所有的引入物种都是入侵物种。

Many introduced – or non-native – species thrive in new areas without posing any threat.

许多引入的物种或非本地物种在新环境中茁壮成长，而不构成任何威胁。

In some cases, invasive species have changed the natural world beyond recognition, so let's look at the different ways they can be problematic.

在某些情况下，入侵物种已经改变了自然世界，所以让我们看看它们是如何成为问题的。

First of all, invasive species may eat native species, or sometimes they may bring a disease with them, which native species have never faced before and therefore have no defences against.

首先，入侵物种可能会吃掉本地物种，或者有时它们会带来一种疾病，而本地物种从未面对过这种疾病，因此它们没有防御机制来对抗这种疾病。

Often the invasive species breed very quickly – which further adds to the problem of native species losing their sources of food.

入侵物种繁殖速度非常快，这进一步加剧了本地物种失去食物来源的问题。

Species invasions are one of the biggest causes of damage in an ecosystem, actually putting its survival at risk.

物种入侵是生态系统中最大的破坏因素之一，实际上增加了物种生存的风险。

So, how do invasive species spread?

那么，入侵物种是如何传播的呢？

Without a doubt, the biggest cause is human activity.

毫无疑问，最大的原因是人类活动。

This could be intentional, or it could be accidental, such as when people who've been on holiday in another country come back with, say, the seeds of plants on their clothes or shoes.

这可能是有意的，也可能是无意的，比如人们在其他国家度假回来时，衣服或鞋子上可能带有植物的种子。

Plants and animals, especially insects, arrive in or on the cargo of ships, and then escape into their new 'home'.

植物和动物，尤其是昆虫，会随着货船的货物进入或附着在上面，然后逃到它们的新‘家’。

But sometimes humans deliberately move animals and plants around the world, for example to use them to control pests on farms, or to be pets.

但有时人类会故意将动物和植物带到世界各地，比如为了控制农场上的害虫，或者作为宠物。

This can go very wrong if those animals and plants move into wild settings and start breeding or begin growing in ways that weren't predicted.

如果那些动物和植物进入野生环境并开始繁殖或生长，情况可能会变得非常糟糕。

Let's now look at an example of an invasive species here in Australia: Rhinella marina is a species of toad that was deliberately introduced from Hawaii in 1935 as a form of biological control.

现在让我们来看澳大利亚的一个入侵物种的例子：Rhinella marina 是一种来自夏威夷的蟾蜍，于1935年被故意引入作为生物控制的一种方式。

It was hoped that the toads would eat the grey-backed beetles responsible for destroying crops of sugar on many of the plantations.

人们希望这些蟾蜍能吃掉负责毁坏许多种植园甘蔗的灰背甲虫。

At first, just a handful of toads were released by scientists into Queensland, but this number soon grew as other states followed suit.

最初，科学家们只在昆士兰释放了少量的蟾蜍，但这个数字很快增长，因为其他州也跟着效仿。

Within two years, 62, 000 young toads had been released into the wild.

在两年内，62, 000 只年轻的蟾蜍被释放到野外。

The toads did nothing to protect the plantations, but they did reproduce rapidly and could soon be found all over the northern half of the country.

这些蟾蜍对种植园没有任何保护作用，但它们繁殖迅速，很快遍布了国家北部的一半地区。

The toads are poisonous at every stage of their life cycle, and anything that eats them will die.

蟾蜍在其生命周期的每个阶段都是有毒的，任何吃它们的生物都会死亡。

My second example regarding invasive species is the United Kingdom.

我关于入侵物种的第二个例子是英国。

Actually, there are more than three-thousand invasive species there, including some that are extremely common.

实际上，那里有超过三千种入侵物种，包括一些非常常见的种类。

Some invasive plants, such as Japanese knotweed, have had a devastating impact on parts of the UK.

一些入侵植物，比如日本藤，对英国的部分地区造成了毁灭性的打击。

Gardeners in the nineteenth century considered it a beautiful ornamental plant – which it is, when it's kept under control – but it soon spread into the countryside and remains a problem even to this day as it's so hard to eradicate.

19世纪的园艺者认为它是美丽的观赏植物——当它受到控制时是这样的——但它很快蔓延到乡间，并且即使到现在，它也仍然是一个难题，因为很难根除。

Another invasive plant is rhododendrons, which can be found in UK parks and woodlands.

另一种入侵植物是杜鹃花，它们可以在英国的公园和林地找到。

Their introduction dates back to 1763, but they're now seen as harmful because they block out so much light that native wild flowers can't grow beneath them.

他们的引入可以追溯到1763年，但如今人们认为它们有害，因为它们遮挡了太多光线，使得本土野生花卉无法在它们下面生长。

And then there are grey squirrels, which are one invasive species almost everyone in the UK will have come across.

还有灰 squirrels，几乎每个人在英国都见过这种入侵物种。

They were brought to the UK from North America and introduced to private estates around the 1870s but are now found everywhere, from forests to city squares.

它们是从北美引进的，并在19世纪70年代左右被引入到英国的私人庄园，但现在它们遍布各地，从森林到城市广场。

Grey squirrels have outcompeted the smaller, native red squirrels.

灰松鼠在竞争中胜过了体型较小的本土红松鼠。

They both eat the same food, and the grey squirrels carry a type of virus that is deadly to the red squirrels.

它们吃的食物相同，而灰色松鼠携带一种对红松鼠致命的病毒。

Red squirrel populations have collapsed, and there are only a handful of sites left in the UK where they're found.

红松鼠的数量已经崩溃，目前在英国只有少数几个地方还能找到它们。

An important question for ecologists worldwide is, what can we do to tackle the problem of invasive species?

生态学家们面临的一个重要问题是，我们能做些什么来解决入侵物种的问题？

The first step in controlling invasive species is learning about the behaviour of new species coming into the country.

控制入侵物种的第一步是了解新物种进入国家后的行为。

Monitoring is an important part of this, so that we can know if the new species begins to have a negative impact in its new environment.

监测是其中一个重要部分，这样我们才能知道新物种是否开始对它们的新环境产生负面影响。

One effective way to keep track of invasive species is to create a database for the whole country.

一种有效的方法是为整个国家创建一个数据库来跟踪入侵物种。

That way, all relevant authorities and agencies can share important information and take whatever action's needed.

这样，所有相关的权威机构和机构都可以分享重要的信息并采取必要的行动。

But the public also have a vital role to play in this process.

但是公众在这个过程中也扮演着至关重要的角色。

They should be encouraged to photograph harmful species – because this helps with identification – and then to report when and where these were observed.

他们应该被鼓励拍摄有害物种的照片——因为这有助于识别——然后报告他们在哪里发现这些物种。

But it's important to tell people not to destroy or even touch what they've found.

但是，重要的是要告诉人们不要破坏或甚至触摸他们发现的东西。

Now, I'm going to move on to …

现在，我要继续到……