The parrot, the poo and the parasitic flower
John Pickrell is the editor of Australian Geographic. He is a science writer, author, nature lover and self-confessed geek. Blog posts range over Southern Hemisphere palaeontology, dinosaurs, megafauna, archaeology, palaeoanthropology and a smattering of other topics.
THIS IS a tale of two strange and fascinating species, both of which evolved unusual life histories during millions of years of isolation on the islands of New Zealand – two species that, we now know, once had a close ecological relationship.
The first is the kakapo: a large, fragrant, nocturnal bird, and the world’s only flightless parrot – its numbers have dwindled to about 125, most of which are found on Codfish Island, a small speck off the south of the South Island. Here the kakapo’s breeding success is linked to the infrequent fruiting of a single tree, the rimu.
The second, you’re less likely to have heard of. It’s Dactylanthus taylorii, also known as the Hades flower or wood rose, or as ‘pua o te reinga’ to the Māori, which means ‘flower of the underworld’.
A flower with no leaves or roots
It’s a parasitic plant, which can’t photosynthesise and has no leaves or roots. It spends most of its life underground, where it lives swaddled around the roots of the native trees from which it draws its water and nutrients.
For just a few weeks in early autumn each year, Dactylanthus plants throw up large numbers of dull pinky-brown flowers, which emerge from the ground around the host trees. These stud the forest floor, emit a musky, fruity scent and produce copious quantities of nectar to attract the New Zealand lesser short-tailed bat, the plant’s key pollinator.
Unusually for a bat (another NZ quirk), this species spends much of its time crawling on the ground and burrowing in leaf litter.
But a study of fossilised dung or ‘coprolites’ found in a cave in the north-western corner of the South Island in 2012 suggests the plant once had other pollinators, too.
Researchers led by Dr Jamie Wood at Landcare Research in Canterbury have revealed that a series of 900-year-old kakapo droppings are packed with Dactylanthus pollen, suggesting that these birds once consumed its nectar and helped to pollinate the flowers.
Similar to the kakapo, Dactylanthus has been reduced to just 4 per cent of its historic range – but both species were once common across the North Island and the north of the South Island.
Coprolites and ancient ecological relationships
“Kakapo and potentially many other nectar-drinking birds once fed on the nectar of Dactylanthus flowers, and may also have acted as pollinators or seed dispersers for the plant,” Jamie says. “Coprolites are one of the only ways to reconstruct important pre-human ecological relationships, such as pollination and seed dispersal, which must be restored to conserve these species over the long term.”
Intriguingly, in 2012 eight kakapo were reintroduced to Little Barrier Island, 80km north of Auckland on the North Island, one of the remaining Dactylanthus strongholds. This meant that the plant and its historic pollinator were once again brought together.
In 2015, for the first time, a series of camera traps has been installed on the island to attempt to find out if the ancient ecological relationship has been restored. It remains to be seen if any of the cameras have yet photographed instances of kakapo feeding on Hades flowers.
John Pickrell is the author of Flying Dinosaurs: How fearsome reptiles became birds, published by NewSouth Books in 2014. Follow him on Twitter @john_pickrell.