How Bush Pigs Saved Madagascar’s Baobabs丛林猪如何拯救马达加斯加的猴面包树

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.

马达加斯加的猴面包树以其粗壮的树干和细小的树枝点缀着当地的风景。按理说，它本不可能存活到今天。科学家们认为，猴面包树的巨大种子被曾在岛上游荡的巨龟和巨狐猴散播出去。由于人类活动，这些动物物种在1000多年前就灭绝了，猴面包树也应该随之消失。

但事实并非如此。马达加斯加塔那那利佛大学的塞赫诺·安德里安察拉拉扎和美国加利福尼亚大学伯克利分校的翁贾·拉扎芬德拉齐马认为，他们可能找到了其中的原因。

这两位科学家与他们的同行一起，对马达加斯加西部地区的15个树冠进行监测，以确定是否有动物在为猴面包树传播种子。研究人员还在地面上含有种子的果实周围设置“相机陷阱”，并在沿途遇到的粪便中寻找猴面包树种子的踪迹。

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.

他们在美国《热带生物学》杂志上发表报告说，摄像头4次捕捉到一种本地啮齿类动物在捣鼓整颗果实。虽然摄像头没有捕捉到这种啮齿动物打开果实的镜头，但研究小组确实发现了13个被啃咬过的果实，里面的种子也消失了。虽然咬痕不够清晰，无法确定谁是“罪魁祸首”，但这清楚地证明，有某种动物在传播种子。随后，研究人员又找到了生态学上的确凿证据：他们在7堆不同的丛林猪粪便中发现了猴面包树种子。

这一发现不无讽刺意味。科学家们认为，在5000年前到1000年前的某个时候，人类将丛林猪带到马达加斯加，当时正是巨狐猴和巨龟走向灭绝的时候。丛林猪的到来对猴面包树而言是个好消息——尤其是考虑到科学家们已经确定，猴面包树种子在丛林猪消化系统中的经历并不会妨碍其发芽能力。

这一发现本身很重要，而且它也提供了宝贵的证据，证明外来物种可能并非完全有害。例如，马达加斯加的丛林猪虽然不是本地物种，但它们对本地物种的生存起到了重要作用。在南美洲，原产于欧洲的兔子与某些本土植物之间也可能存在类似的关系。安德里安察拉拉扎博士认为，这表明，人类应当先考虑外来物种在生态系统方方面面发挥的作用，然后再谈其可能造成的物种灭绝。

Word Bank

disperse /dɪ'spɜːs/ v. 散布；传播

mantle /'mæntl/ n. 责任，职责

smoking gun 确凿的证据

hamper /'hæmpə（r）/ v. 妨碍；阻止