of the greatest threats to biodiversity in human history.

人類歷史上對生物多樣性的最大威脅之一。

That threat is a recently discovered

這種威脅是最近發現的

fungus and its victims are these guys. Yes frogs. In this case, the extremely rare yellow

真菌和它的受害者是這些傢伙。是的，青蛙。在這種情況下，極其罕見的黃色

legged frog. These elusive amphibians have lost over 80% of their population, due to

腿蛙。這些難以捉摸的兩棲類動物已經失去了80%以上的數量，原因在於

an extremely deadly fungal infection. And they aren't the only species at risk, the frogs

一種極其致命的真菌感染它們並不是唯一處於危險之中的物種，青蛙

are part of a larger global amphibian crisis that is brought 32% of all the known species

是更大的全球兩棲動物危機的一部分，這給所有已知物種帶來了32%的危機。

of frogs, salamanders and caecilians to the brink of extinction in no small part due to

蛙類、蠑螈和尾蚴類動物瀕臨滅絕，這在很大程度上是由於它們的繁殖力不足。

this fungus.

這種真菌。

This loss of biodiversity threatens to have a wide ranging impact from disrupting habitats,

這種生物多樣性的喪失有可能造成廣泛的影響，從破壞生境。

to preventing the advancement of medical research.

以防止醫學研究的進步。

Now, scientists are heading out to the mountains, in an effort to save

現在，科學家們正向山裡走去，努力拯救這群動物。

this important species before it's too late.

這個重要的物種，在它太晚之前。

When we talk about that mountain yellow legged frogs were really talking about two

當我們說到那座山的時候，黃腿蛙真的是在說兩隻。

species, Rana muscosa which is the southern species and Rana sierrae,

種，南方種Rana muscosa和Rana sierrae。

which is the northern species that occurs north of Mather Pass.

這是發生在馬瑟關以北的北方物種。

Both species are very closely related, and they both live

這兩個物種的關係非常密切，它們都生活在

in very high alpine lakes, usually above 8,000 feet.

在非常高的高山湖泊中，通常在8000英尺以上。

These unique frogs weren't always rare. In fact, their numbers were abundant before

這些獨特的青蛙並不總是罕見的。事實上，在它們出現之前，它們的數量已經很豐富了

more people began to settle around the Sierra Nevada Mountains in the late 1800s.

19世紀末，更多的人開始在內華達山脈周圍定居。

There are reports of people in the early 1920s, you know, not being able to walk through a

有報道稱，在20世紀20年代早期，人們不能通過一個走過

meadow without stepping on a frog.

草地上沒有踩到青蛙。

Those same settlers led to the initial decline of the frog population.

這些定居者也導致了青蛙數量的最初下降。

In order to attract tourists and fishermen, they brought non native fish species to the

為了吸引遊客和漁民，他們把非在地的魚種帶到這裡來。

Sierra, specifically trout. Trout happened to feed on tadpoles and young frogs.

塞拉利昂，特別是鱒魚。鱒魚正好以蝌蚪和幼蛙為食。

So, unsurprisingly, the amount of frogs in the Sierra quickly plummeted when they arrived,

所以，不出所料，青蛙到了塞拉利昂後，數量迅速銳減。

The fish started being removed in the 1990s, and that did lead to a rebound,

上世紀90年代，魚開始被清除，這確實導致了反彈。

but a far greater threat was on the horizon.

但更大的威脅就在眼前。

Unfortunately, not very long after that is when the fungal disease chytridiomycosis

不幸的是，沒過多久就是真菌病的時候了。

comes into the Sierra Nevadas.

進入內華達山脈。

Chytridiomycosis is caused by the fungus batrachochytrium dendrobatidis.

枯草桿菌病是由真菌batrachochytrium dendrobatidis引起的。

We sometimes just call it BD for short,

我們有時就簡稱它為BD。

sometimes we just call it chytrid. It was only first written about in 1998. So, there's

有時我們就叫它 "茜草"。它在1998年才第一次被寫到。所以，有

still a lot we don't know about this disease, but its discovery has been a huge breakthrough

我們對這種疾病還有很多不瞭解，但它的發現是一個巨大的突破。

and understanding why amphibian populations have been declining so rapidly.

並瞭解為什麼兩棲動物的數量會如此迅速地下降。

And, unfortunately, it also has

而且，不幸的是，它也有

somehow spread. Literally throughout the world.

以某種方式傳播。從字面上看，整個世界。

So on every continent where frogs exist, chytridiomycosis also exists.

所以在每一個有青蛙存在的大陸上，也存在著恙蟲病。

It's responsible for a third of the world's amphibians becoming threatened.

它要為世界上三分之一的兩棲動物受到威脅負責。

We already believe that about 100 species have gone extinct because of chytridiomycosis.

我們已經相信，大約有100個物種因為枯草桿菌病而滅絕了。

Of course there are other factors that are affecting amphibian populations like

當然，影響兩棲動物種群的還有其他因素，如

habitat loss, invasive species and climate change, but chytrid is recognized as a major

生境喪失、入侵物種和氣候變化，但人們認識到恙蟲病是一個主要的問題。

factor, and its lethal effects can be attributed to the unique way that a frog can breathe.

因素，它的致命作用可以歸結為青蛙獨特的呼吸方式。

The frogs osmoregulate through their skin which just means that their skin is permeable

青蛙是通過皮膚進行滲透調節的，也就是說它們的皮膚是可以滲透的。

and water and gases can really kind of pass through the skin. Frogs can stay underwater

而水和氣體真的可以通過皮膚。青蛙可以呆在水下

for a very long period of time because they can absorb oxygen, through their skin that

因為它們可以通過皮膚吸收氧氣，所以可以持續很長時間

way. Unfortunately, it also means they can absorb fungal spores, and those fungal spores

的方式。不幸的是，這也意味著他們可以吸收真菌孢子，而這些真菌孢子

that they're when their body reacts to it. What it does is it tries to slough off that

他們是當他們的身體對它的反應。它所做的是，它試圖脫落，

infected skin, and it's impossible for them to slough off enough to get rid of

感染的皮膚，而且它們不可能脫落，足以去除

it, and eventually what happens is they die of heart failure.

它，最終發生的事情是他們死於心臟衰竭。

So once the fungus is present in the water. There's really no way for the frogs to get

所以一旦水裡有了真菌。青蛙就真的沒有辦法了。

around it.

圍繞著它。

I think what makes it so difficult is that it's so ubiquitous just in the water supply.

我想，之所以這麼困難，是因為它僅僅在供水方面就無處不在。

You know how do you treat the entire range of the Sierra Nevada Mountains?

你知道如何對待整個內華達山脈的範圍嗎？

Since treating native habitat is out. That means the frogs must be inoculated back at

既然處理原生棲息地是出。那就意味著蛙類必須在接種回

the lab at the Oakland Zoo. Fortunately, the researchers here have a plan to treat and

奧克蘭動物園的實驗室。幸運的是，這裡的研究人員有一個計劃來治療和。

release their yellow legged patients back into the wild. And the solution starts by

把他們的黃腿病人放回野外。解決辦法是

getting to the frogs early before they're technically frogs at all

趁著青蛙還沒變成青蛙的時候，早點找到它們

Chytridiomycosis is really just affects the keratin on the frog. Keratin is, you know,

枯草菌病其實只是影響青蛙的角質。角蛋白是，你知道的。

a human it's like your fingernails or your hair that kind of thing but on frogs their

人的指甲或頭髮之類的東西，但在青蛙身上，它們的。

their keratin their keratinized skin is really in that webbing between their toes and on

他們的角質，他們的角質化的皮膚 真的是在他們的腳趾之間的網狀物，並在上

the inside of their thighs. It's where the skin is more permeable. As tadpoles, the only

他們的大腿內側。這裡的皮膚更容易被滲透。作為蝌蚪，唯一的

keratinized part of the body is the mouthparts.

角質化的部分是口器。

And so it doesn't seem to have a major effect on tadpoles.

所以似乎對蝌蚪的影響不大。

But just getting a hold of some tadpoles is an ordeal, because of the frogs' remote

但僅僅是抓到一些蝌蚪，就是一種煎熬，因為青蛙的遠程

habitat, a helicopter trip courtesy of a partnership with the California Department of

棲息地，與加利福尼亞州政府合作提供的直升機旅行。

Fish & Wildlife is needed to retrieve the healthy tadpoles from their mountainous

需要漁民和野生動物將健康的蝌蚪從他們的山裡找回來。

dwelling.

住所。

Once in the lab, Rousser's team will raise the frogs under optimal conditions,

一旦進入實驗室，Rousser的團隊將在最佳條件下飼養青蛙。

until they're ready for a high tech upgrade.

直到他們準備好進行高科技升級。

Our goal is to bring them up to a size of 40 millimeters measured from their tip of

我們的目標是使它們的尺寸達到40毫米，從它們的頂端測量。

their snout to the tip of their back end, it's called the snout vent length. And the

他們的鼻子到他們的後端尖端， 這就是所謂的鼻孔長度。而

reason for that is because then we can implant them with a microchip. So basically,

因為我們可以給他們植入芯片所以，基本上，

frog cyborgs, it's just

蛙類電子人，它只是...。

like the microchip that you would use for your dog or cat, that allows us then to track

就像你用在你的狗或貓身上的微芯片一樣 讓我們能夠追蹤到...

those frogs over the long term after they've been released. Okay, maybe not

這些青蛙在被放生後的長遠發展。好吧，也許不是

full on cyborgs, but the implanted microchip does allow the California Department of Fish

完全的電子人，但植入的微芯片確實允許加州魚類部。

and Wildlife to scan the frogs and track them for several years after being released into

在放生後的數年內，掃描這些青蛙並跟蹤它們。

the wild. Once they're fully formed and ready, the frogs are intentionally exposed to the

野生的。一旦它們完全成型並準備好了 青蛙就會被故意暴露在野外。

fungus, which is done under close supervision of course.

菌，當然是在嚴密的監督下進行的。

We actually test them every single week we treat them at about three weeks, or when they

其實我們每一個星期都會對他們進行測試，我們在大約三週的時候對他們進行治療，或者當他們

reach 600,000 copies of the critical infection intensity. So ideally we want them

達到60萬份的臨界感染強度。所以，理想情況下，我們希望他們

to develop a moderate level of infection, allow their immune systems to kick in and

形成中等程度的感染，讓他們的免疫系統開始發揮作用，並讓他們的免疫系統發揮作用。

then we treat them. And then that way when they go back to the wild and they're released.

然後我們對它們進行治療。然後這樣，當他們回到野外，他們被釋放。

They may get a moderate level of the infection, but they're never going to get so

他們可能會得到一箇中等程度的感染，但他們永遠不會得到這樣的。

sick that it's going to kill them

噁心，它會殺死他們

After the frogs have been microchipped, treated, observed and have built up an

在對青蛙進行了芯片植入、治療、觀察，並建立了一個

immunity to chytrid, it's back to the helicopter for return to their home in the mountains.

免疫了恙蟲病，就回到直升機上，回到山裡的家。

It may seem like a lot of work for a small group of rare frogs.

對於一小群珍稀的青蛙來說，這似乎是一件很辛苦的事情。

But amphibians are much more important to people than may be readily apparent.

但兩棲類動物對人們的重要性遠比表面上看到的要大得多。

Not everybody notices their inherent beauty and worth what I usually say to people is

不是每個人都會注意到自己的內在美和價值我通常對人們說的是

well. How do you feel about mosquito-borne illnesses? There are a lot of problems that

嘛。你如何看待蚊子傳播的疾病？有很多問題

can be caused by mosquitoes and frogs eat mosquitoes.

可由蚊子引起，青蛙吃蚊子。

The other thing is that tomorrow's medicines may come from frogs.

另外就是明天的藥品可能來自於青蛙。

In addition to being vital to medical research and saving us from mosquito-borne illnesses,

除了對醫學研究至關重要，讓我們免受蚊子傳播的疾病困擾外。

which honestly already seems like enough.

說實話，這已經顯得足夠了。

Frogs can also tell us about how healthy our ecosystem is and what

青蛙還可以告訴我們，我們的生態系統有多健康，以及我們的生態環境有多好。

dangers might be right around the corner.

危險可能就在眼前。

Frogs are considered an indicator species, which means that because they are very

青蛙被認為是一種訓示性物種，這意味著，由於它們非常

sensitive and absorb through their skin, they're going to be the first thing to react to

敏感，並通過皮膚吸收，他們將是第一個反應，以

some sort of pollutants or chemical in your system, and because they're amphibians,

某種汙染物或化學品在你的系統， 因為他們是兩棲動物，

they can alert you to problems on water and on land.

它們可以提醒你注意水面和陸地上的問題。