How Bush Pigs Saved Madagascar’s Baobabs叢林豬如何拯救馬達(dá)加斯加的猴面包樹

The Malagasy baobab tree， whose thick trunks and tiny branches dot Madagascar’s landscape， could not， by rights， have survived to the present day. Scientists believe that its large seeds were once dispersed by the giant tortoises and giant lemurs that roamed the island. When these species went extinct over one thousand years ago owing to human activity， the baobab tree should have vanished too.

It did not. Seheno Andriantsaralaza at the University of Antananarivo in Madagascar and Onja Razafindratsima at the University of California， Berkeley， the US， think they may know the reason why.

Together with their colleagues， the scientists monitored 15 tree canopies in a western region of Madagascar， to identify any animals that might have claimed the mantle of baobab-seed disperser. The researchers also set up camera traps around seed-containing fruits lying on the ground， and searched any faeces that they encountered along the way for the presence of seeds.

馬達(dá)加斯加的猴面包樹以其粗壯的樹干和細(xì)小的樹枝點(diǎn)綴著當(dāng)?shù)氐娘L(fēng)景。按理說，它本不可能存活到今天?？茖W(xué)家們認(rèn)為，猴面包樹的巨大種子被曾在島上游蕩的巨龜和巨狐猴散播出去。由于人類活動(dòng)，這些動(dòng)物物種在1000多年前就滅絕了，猴面包樹也應(yīng)該隨之消失。

但事實(shí)并非如此。馬達(dá)加斯加塔那那利佛大學(xué)的塞赫諾·安德里安察拉拉扎和美國(guó)加利福尼亞大學(xué)伯克利分校的翁賈·拉扎芬德拉齊馬認(rèn)為，他們可能找到了其中的原因。

這兩位科學(xué)家與他們的同行一起，對(duì)馬達(dá)加斯加西部地區(qū)的15個(gè)樹冠進(jìn)行監(jiān)測(cè)，以確定是否有動(dòng)物在為猴面包樹傳播種子。研究人員還在地面上含有種子的果實(shí)周圍設(shè)置“相機(jī)陷阱”，并在沿途遇到的糞便中尋找猴面包樹種子的蹤跡。

They report in the US journal Biotropica that a native rodent was caught on camera handling whole fruits on four occasions. Although there was no footage of the rodent breaking the fruits open， the team did stumble upon 13 fruits that had been chewed into and had their seeds removed. Though the bite marks were not clear enough to identify a culprit， this was clear evidence that a seed-distributing animal was out there. They then found the ecological equivalent of a smoking gun： baobab seeds in seven different piles of bush-pig dung.

The discovery is not without irony. Scientists believe bush pigs were brought to Madagascar by humans sometime between 1，000 and 5，000 years ago， just as the giant lemurs and tortoises were going extinct. Their arrival was a lucky break for the baobabs—especially as scientists have determined that a seed’s journey through the porcine digestive system does not hamper its ability to germinate.

While the finding is important in its own right， it also provides valuable evidence that introduced species may not be entirely harmful. Madagascar’s pigs， for example， though not native， have made themselves essential to the survival of the native species. Similar relationships are suspected to hold in South America between rabbits native to Europe and some native plants. For Dr Andriantsaralaza， that suggests the full ecological role of introduced species should be considered before talk of extermination they might cause begins.

他們?cè)诿绹?guó)《熱帶生物學(xué)》雜志上發(fā)表報(bào)告說，攝像頭4次捕捉到一種本地嚙齒類動(dòng)物在搗鼓整顆果實(shí)。雖然攝像頭沒有捕捉到這種嚙齒動(dòng)物打開果實(shí)的鏡頭，但研究小組確實(shí)發(fā)現(xiàn)了13個(gè)被啃咬過的果實(shí)，里面的種子也消失了。雖然咬痕不夠清晰，無(wú)法確定誰(shuí)是“罪魁禍?zhǔn)住?，但這清楚地證明，有某種動(dòng)物在傳播種子。隨后，研究人員又找到了生態(tài)學(xué)上的確鑿證據(jù)：他們?cè)?堆不同的叢林豬糞便中發(fā)現(xiàn)了猴面包樹種子。

這一發(fā)現(xiàn)不無(wú)諷刺意味?？茖W(xué)家們認(rèn)為，在5000年前到1000年前的某個(gè)時(shí)候，人類將叢林豬帶到馬達(dá)加斯加，當(dāng)時(shí)正是巨狐猴和巨龜走向滅絕的時(shí)候。叢林豬的到來(lái)對(duì)猴面包樹而言是個(gè)好消息——尤其是考慮到科學(xué)家們已經(jīng)確定，猴面包樹種子在叢林豬消化系統(tǒng)中的經(jīng)歷并不會(huì)妨礙其發(fā)芽能力。

這一發(fā)現(xiàn)本身很重要，而且它也提供了寶貴的證據(jù)，證明外來(lái)物種可能并非完全有害。例如，馬達(dá)加斯加的叢林豬雖然不是本地物種，但它們對(duì)本地物種的生存起到了重要作用。在南美洲，原產(chǎn)于歐洲的兔子與某些本土植物之間也可能存在類似的關(guān)系。安德里安察拉拉扎博士認(rèn)為，這表明，人類應(yīng)當(dāng)先考慮外來(lái)物種在生態(tài)系統(tǒng)方方面面發(fā)揮的作用，然后再談其可能造成的物種滅絕。

Word Bank

disperse /d?'sp??s/ v. 散布；傳播

mantle /'m?ntl/ n. 責(zé)任，職責(zé)

smoking gun 確鑿的證據(jù)

hamper /'h?mp?（r）/ v. 妨礙；阻止