中國(guó)大鯢保育困境：放生反致野生品種走向滅絕

The Chinese giant salamander, the world’s largest amphibian and a critically endangered species, has quietly slipped toward extinction in nature. Following an exhaustive, yearslong search, researchers recently reported that they were unable to find any wild-born individuals.

作為世界上最大的兩棲動(dòng)物和極危物種，中國(guó)大鯢已經(jīng)悄然在大自然中走向滅絕。經(jīng)過(guò)長(zhǎng)達(dá)數(shù)年的徹底搜索，研究人員前不久報(bào)告稱，他們無(wú)法找到任何野生的大鯢個(gè)體。

“When we started the survey, we were sure we’d at least find several salamanders,” said Samuel Turvey, the lead author and a senior research fellow at the Zoological Society of London.

“開(kāi)始調(diào)查時(shí)，我們覺(jué)得肯定至少能找到幾條大鯢，”該研究的第一作者、倫敦動(dòng)物學(xué)會(huì)(Zoological Society of London)的高級(jí)研究員塞繆爾·特維(Samuel Turvey)說(shuō)。

“It’s only now that we’ve finished that we realize the actual severity of the situation.”

“直到現(xiàn)在調(diào)查結(jié)束了，我們才意識(shí)到情況的嚴(yán)重性。”

Millions of giant salamanders live on farms scattered throughout China, where the animals are bred for their meat. But another study by Dr. Turvey and his colleagues shows that reintroducing farmed animals is not a simple solution for saving the species in the wild.

數(shù)以百萬(wàn)計(jì)的大鯢生活在中國(guó)各地的養(yǎng)殖場(chǎng)里，作為肉類來(lái)源被飼養(yǎng)。但特維和同事們的另一項(xiàng)研究表明，往大自然中重新引入飼養(yǎng)的動(dòng)物并不是拯救野生物種的一個(gè)簡(jiǎn)單方法。

In the wild, Chinese giant salamanders were not just one species but at least five, and perhaps as many as eight. On farms, they are being muddled into a single hybridized population adapted to no particular environment.

在野外，中國(guó)大鯢不是只有一個(gè)種，而是至少包括五個(gè)物種，甚至可能多達(dá)八個(gè)。但在養(yǎng)殖場(chǎng)里，它們被混合成了一個(gè)雜交品種，不適應(yīng)任何特定的環(huán)境。

“The farms are driving the extinction of most of the species by homogenizing them,” said Robert Murphy, a co-author and senior curator of herpetology at the Royal Ontario Museum. “We’re losing genetic diversity and adaptations that have been evolving for millions of years.”

“這些養(yǎng)殖場(chǎng)正在通過(guò)同質(zhì)化加速多數(shù)大鯢物種的滅絕，”該研究的聯(lián)合作者、皇家安大略博物館(Royal Ontario Museum)的爬行動(dòng)物學(xué)高級(jí)策展人羅伯特·墨菲(Robert Murphy)說(shuō)，“我們正在失去進(jìn)化了數(shù)百萬(wàn)年的基因多樣性和適應(yīng)性。”

As with so many other protected species in China, poaching is the main threat to giant salamanders, which can weigh up to 140 pounds. Unlike pangolins, tigers and rhinos, however, salamanders were never historically valued as meat, trophies or medicine.

和中國(guó)的其他許多受保護(hù)物種一樣，偷獵是重量可達(dá)140磅的大鯢的主要威脅。不過(guò)，與穿山甲、虎和犀牛不同的是，大鯢在歷史上從未被視為珍貴的肉類、狩獵紀(jì)念物或藥材。

“Traditional knowledge associated them with bad luck and dead babies,” Dr. Turvey said. “They were animals you didn’t want to go near.”

“傳統(tǒng)觀念將它們與壞運(yùn)氣和死去的嬰兒聯(lián)系在一起，”特維說(shuō)，“它們是你不想走近的動(dòng)物。”

That changed in the mid-20th century when famine forced people to turn to alternative food sources. By the 1990s, giant salamander meat had been rebranded as a luxury food item in China, and government-subsidized salamander farms began popping up around the country.

這種情況在20世紀(jì)中期發(fā)生了變化，當(dāng)時(shí)，饑荒迫使人們轉(zhuǎn)向其他食物來(lái)源。到了20世紀(jì)90年代，大鯢的肉在中國(guó)被重新定義為一種奢侈食品，政府補(bǔ)貼的大鯢養(yǎng)殖場(chǎng)開(kāi)始在中國(guó)遍地開(kāi)花。

As prices for live animals skyrocketed, captive populations grew and wild ones plummeted. “The development of this industry led to huge amounts of increased pressure on salamanders, which were poached from the wild to stock these farms,” Dr. Turvey said.

隨著活體大鯢的價(jià)格飛漲，圈養(yǎng)大鯢的數(shù)量開(kāi)始增加，野生大鯢的數(shù)量銳減。“這個(gè)行業(yè)的發(fā)展給大鯢帶來(lái)了巨大的壓力，它們被從野外捕獵來(lái)放進(jìn)養(yǎng)殖場(chǎng)，”特維說(shuō)。

Realizing the amphibians were disappearing in nature, officials decided to restock wild populations by releasing captive-born salamanders.

官員們意識(shí)到這種兩棲動(dòng)物正在從自然界中消失，決定釋放人工繁殖的大鯢，以增加野生大鯢的數(shù)量。

But what seemed like a good conservation strategy led to a number of new problems, Dr. Turvey said.

但特維表示，這個(gè)看似很好的保護(hù)策略導(dǎo)致了許多新問(wèn)題。

Not recognizing that salamanders from different parts of the country were distinct species, farmers had inadvertently created hybrids — a fact that the researchers confirmed through genetic analysis of over 1,000 captive amphibians.

不知道國(guó)內(nèi)各地區(qū)大鯢物種有明顯差異的農(nóng)民，無(wú)意間創(chuàng)造出了雜交品種——通過(guò)對(duì)捕撈的1000多條大鯢進(jìn)行基因分析，研究人員證實(shí)了這一點(diǎn)。

“When we looked at farmed animals, we found a large mixture of different genetic components, like a witch’s caldron,” said Jing Che, a herpetologist at the Kunming Institute of Zoology and co-author of both recent studies.

“當(dāng)我們觀察養(yǎng)殖動(dòng)物的時(shí)候，我們發(fā)現(xiàn)了不同基因組成的大量混合，就像一口女巫的大鍋，”昆明動(dòng)物研究所的爬行動(dòng)物學(xué)家、近兩個(gè)研究的共同作者車靜說(shuō)道。

No system was ever put in place to prevent hybrids from release into the wild, nor to ensure that reintroduced animals were matched with their geographic origins.

防止雜交物種放生野外的制度始終沒(méi)有建立起來(lái)，也無(wú)法保證重新引入的物種可以匹配它的地域出身。

“These hybrids may create a big mess by changing the genetic makeup of locally adapted wild animals,” Dr. Che said.In 2009, Dr. Murphy and his colleagues raised these concerns at a government meeting but were dismissed. “They just said it wasn’t an issue,” he said.

“這些雜交物種通過(guò)改變已經(jīng)適應(yīng)當(dāng)?shù)氐囊吧鷦?dòng)物的基因組成，可以造成大麻煩，”車靜說(shuō)。2009年，墨菲和他的同事在一個(gè)政府會(huì)議上提出了這些擔(dān)憂，但卻沒(méi)人理會(huì)。“他們就是認(rèn)為這不構(gòu)成問(wèn)題，”他說(shuō)。

At least 72,000 captive-bred salamanders have been released since then. Until now, the cumulative effect of poaching, farming and release on wild populations was unknown.

此后，至少有7.2萬(wàn)條人工養(yǎng)殖大鯢被放歸野外。到目前為止，偷捕、養(yǎng)殖和放歸對(duì)野外數(shù)量的積累效應(yīng)還并不清楚。

So in 2013, Dr. Turvey and his colleagues organized a nationwide giant salamander search — apparently the largest wildlife survey ever conducted in China.

因此，在2013年，特維和同事組織了一場(chǎng)全國(guó)性的大鯢搜尋——這應(yīng)該是在中國(guó)進(jìn)行的最大一次野生動(dòng)物調(diào)查。

They spent three years scanning riverbeds and turning over rocks at 97 sites in 16 provinces. They found giant salamanders at just four sites.

他們花了三年時(shí)間搜尋河床，在16個(gè)省的97個(gè)地點(diǎn)翻找?guī)r石，但只在4處發(fā)現(xiàn)了大鯢。

All of the animals had genetic profiles that did not match the places in which they were living, indicating they likely originated on farms.

所有生物的基因檔案與他們先前的棲息地點(diǎn)均不匹配，這表明他們可能來(lái)自養(yǎng)殖場(chǎng)。

The researchers also interviewed nearly 3,000 local people, about half of whom said they had seen giant salamanders in the wild. But the most recent sightings they could recall took place, on average, 18 years ago.

研究人員還對(duì)將近3000名當(dāng)?shù)厝诉M(jìn)行了采訪，其中約有一半人表示他們?cè)谝巴庖?jiàn)過(guò)大鯢。但在他們回憶中最后一次看見(jiàn)大鯢，平均都是在18年前。

“There could be remnant populations of genuine salamanders scattered here and there, but they are effectively impossible for any researchers to find now,” Dr. Turvey said.Given that, the best strategy for preventing extinction in the wild, he added, is to rescue genetically pure animals from farms, and then undertake carefully controlled conservation breeding to rebuild each species’ numbers.

“可能多多少少還有一些純種大鯢的殘存，但事實(shí)上，現(xiàn)在任何研究人員都不可能找到它們，”特維說(shuō)。他還說(shuō)，鑒于這個(gè)情況，避免物種在野外滅絕的最好辦法，就是拯救養(yǎng)殖場(chǎng)里的純種大鯢，然后進(jìn)行謹(jǐn)慎控制的保護(hù)育種，重建每個(gè)物種的數(shù)量。

“If we wait too long, all those wild-caught individuals will be gone,” he said.

“要是我們等待太久，野外捕獲的那些個(gè)體就都沒(méi)了，”他說(shuō)。

Releases of giant salamanders without knowing their genetic makeup should stop immediately, Dr. Che added. But that can’t happen without buy-in from Chinese authorities.

車靜補(bǔ)充說(shuō)，應(yīng)該立即停止向野外放生未知基因組成的大鯢。但若沒(méi)有中國(guó)政府的首肯，這也無(wú)法實(shí)現(xiàn)。

“We hope to work with the government to improve the existing conservation plan,” Dr. Che said. “We have a responsibility to do conservation based on scientific knowledge.”

“我們希望與政府合作改善現(xiàn)有的保護(hù)計(jì)劃，”車靜說(shuō)。“我們有責(zé)任根據(jù)科學(xué)知識(shí)來(lái)進(jìn)行保護(hù)。”