Fossilized Poop Reveals How Extinct, Flightless Birds Helped Spread New Zealand’s Colorful Fungi
The upland moa was likely drawn to the fungi because of their resemblance to berries, scientists say, allowing the creature to fill a role typically played by mammals
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Scientists can learn a lot about extinct animals by studying their footprints, bones and even teeth. But, while insightful, these artifacts don’t always paint a complete picture of an ancient creature’s diet or behavior. For that information, researchers often turn to another source: fossilized poop.
Fossilized feces—also known as “coprolites”—can shed light on “the last day or two [of] behavior of an animal from hundreds of thousands or millions of years ago,” says Alexander Boast, a paleoecologist at Manaaki Whenua - Landcare Research, to Cosmos’ Evrim Yazgin.
Boast and a team of researchers, for example, are using fossilized dung to learn more about the diets of extinct flightless birds called moa that once roamed around New Zealand. Coprolites helped them confirm that moa feasted on colorful native fungi—and, by doing so, the ostrich-like creatures might have helped maintain healthy forests on the South Pacific island.
They describe their findings in a new paper published last week in the journal Biology Letters.
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Fungi play a vital role in many ecosystems. By breaking down organic matter, they put nutrients back into the soil. And by intertwining with tree roots, they defend the plants against harmful invaders and help them absorb nutrients and water.
Many fungi rely on animals to spread and proliferate. These varieties produce drab-looking but tasty fruiting bodies called truffles, which mammals like dogs or boars will find by smell—then dig up and eat. In the process, these creatures transport the fungi’s spores to new places when they poop.
But, before the arrival of humans, New Zealand did not have any mammals lumbering around and snacking on truffles—the island’s only native mammal species are bats and marine creatures. This got scientists wondering: How were the fungi spreading?
They wondered if the island’s birds, including moa, might have played a role. Some native, truffle-like fungi produce boldly colored fruiting bodies that grow in shades of blue, pink and purple—and to moa, which were known to eat fruit, these fungi might resemble berries.
“Birds have very strong color vision and they will forage predominately by sight,” Boast tells Cosmos. “So it looks like there’s been some kind of mimicry. Effectively, these fungi look like berries on the forest floor, which is remarkable.”
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But proving that the extinct birds ate and spread these native fungi appeared difficult—until scientists stumbled upon the “coprolite of destiny,” as Boast tells Science’s Phie Jacobs. His team was rooting around in a cave when they discovered a piece of fossilized dung in a crevice.
It came from an upland moa (Megalapteryx didinus), one of the nine species of moa that inhabited New Zealand before humans hunted the birds to extinction around 600 years ago. Weighing between 30 and 140 pounds, upland moa were among the smallest of all the moa, reports Stuff’s Caron Copek.
The team also tracked down a second upland moa coprolite that was housed in a museum. When they analyzed samples taken from the two fossilized feces, they found spores and DNA from the colorful native fungi—confirming their hypothesis that moa ate the fungi and helped them spread.
“It’s pretty unambiguous at this point that [moa] were absolutely, definitely eating these things,” Boast tells Science.
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Now, however, with the moa extinct, the fungi are likely not being dispersed as widely or as often.
After Europeans began colonizing New Zealand, non-native mammals, like possums, deer, wallabies and wild pigs, were introduced to the island. But these animals are not interested in eating the vividly colored native fungal fruiting bodies—they’d rather eat smelly, non-native truffles. These non-native fungi, in turn, support the growth of non-native trees, which might outcompete native trees like the southern beech.
This could have major implications for New Zealand’s forest ecosystems, though scientists are still investigating the possible ripple effects of the moa’s demise.
“It’s very cool to look at a past ecosystem, but we’re trying to understand just how complex ecosystems were in the past, and what kind of long-term legacy impacts of extinction might be,” Boast tells Cosmos. “It’s why we see this work as being very important.”
Matthew Smith, a fungal biologist at the University of Florida who was not involved in the work, suggests the native fungi might still have hope, even without the moa to disperse their spores: “Fungi are pretty adaptable,” he tells Science. “I wouldn’t count them out.”
