PART 4

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

你将听到一段关于动植物入侵物种的生态学讲座。

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

首先，你有一些时间查看第31至第40题。

Now listen carefully and answer questions 31 to 40.

现在请仔细听，并回答第31至第40题。

Today I'm going to talk about invasive species. Let me start by saying what an invasive species is and what it's not.

今天我将谈论入侵物种。让我先说说什么是入侵物种，什么不是。

Invasive species are any animal or plant that is introduced into an environment by humans, and which is then harmful to that environment. It's important to be clear that not all introduced species are invasive.

入侵物种是指任何由人类引入某一环境的动物或植物，并对该环境造成危害。重要的是要明确，并非所有引入的物种都是入侵性的。

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

许多引入的——或非本土的——物种在新地区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，入侵物种已经使自然界发生了翻天覆地的变化，所以让我们来看看它们可能造成问题的不同方式。

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土物种，或者有时它们可能携带一种本土物种从未面对过的疾病，因此没有防御能力。

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

通常，入侵物种繁殖非常迅速——这进一步加剧了本土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受损的最大原因之一，实际上使其生存面临风险。

So, how do invasive species spread? Without a doubt, the biggest cause is human activity.

那么，入侵物种是如何传播的？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，比如当人们在另一个国家度假后回来时，衣服或鞋子上带着植物种子。

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，藏在或附在船舶货物中到达，然后逃入它们的新「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.

但有时人类故意在世界各地移动动植物，例如用它们来控制农场上的害虫，或作为宠物。

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.

如果这些动植物进入野外环境并开始以未预料到的方式繁殖或生长，这可能会出现严重问题。

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.

现在让我们看看澳大利亚的一个入侵物种例子：海蟾蜍是一种蟾蜍物种，1935年从夏威夷故意引入作为生物防治手段。

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

人们希望蟾蜍能够吃掉负责毁坏许多种植园甘蔗作物的灰背甲虫。

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

起初，科学家们只在昆士兰州放生了少量蟾蜍，但随着其他州纷纷效仿，这个数字很快增加了。

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

两年内，62,000只幼年蟾蜍被放生到野外。

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.

蟾蜍没有起到保护种植园的作用，但它们确实快速繁殖，很快遍布全国北半部。

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有毒，任何吃了它们的东西都会死亡。

My second example regarding invasive species is the United Kingdom. Actually, there are more than three-thousand invasive species there, including some that are extremely common.

关于入侵物种的第二个例子是英国。实际上，那里有超过三千种入侵物种，其中一些极为常见。

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

一些入侵植物，如虎杖，对英国部分地区产生了毁灭性影响。

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世纪的园丁认为它是一种美丽的观赏植物——当然，在受控时它确实是——但它很快蔓延到农村，直到今天仍然是一个问题，因为它很难根除。

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，可以在英国的公园和林地中找到。

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.

它们的引入可以追溯到1763年，但现在被视为有害的，因为它们遮挡了太多阳光，使得本土野花无法在其下面生长。

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

然后是灰松鼠，这是英国几乎每个人都会遇到的一种入侵物种。

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.

它们从北美被带到英国，大约在1870年代被引入私人庄园，但现在到处都有，从森林到城市广场。

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

灰松鼠已经超过了较小的本土红松鼠。它们都吃同样的食物，而灰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.

红松鼠种群已经崩溃，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? The first step in controlling invasive species is learning about the behaviour of new species coming into the country.

全球生态学家面临的一个重要问题是，我们能做什么来解决入侵物种的问题？控制入侵物种的第一步是了解进入该国的新物种的行为。

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.

监测是其中的重要部分，这样我们就能知道新物种是否开始对其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.

追踪入侵物种的一种有效方法是为整个国家建立一个数据库。

That way, all relevant authorities and agencies can share important information and take whatever action's needed. But the public also have a vital role to play in this process.

这样，所有相关当局和机构可以共享重要信息并采取所需的任何行动，但公众在这一过程中也有重要的作用。

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

应该鼓励他们拍摄有害物种的照片——因为这有助于识别——然后报告观察到这些物种的时间和地点。

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

但重要的是告诉人们不要破坏甚至触摸他们发现的东西。

Now, I'm going to move on to …

现在，我将继续……