Jul 29. () –
New Zealand’s endangered flightless birds are seeking refuge in the same places where six species of their moa relatives last lived before becoming extinct.
An international team of researchers, led by scientists from the University of Adelaide, used fossils and computer models to make the discovery, shedding light on a mystery with important conservation benefits.
“Our research overcame previous logistical challenges to track population dynamics of six moa species at resolutions not previously considered possible,” he said. it’s a statement lead author Associate Professor Damien Fordham, from the University of Adelaide’s Environment Institute.
“We achieved this by combining sophisticated computer models with extensive fossil records, paleoclimate information and innovative reconstructions of people’s colonisation and expansion into New Zealand.
“Our research shows that despite large differences in the ecology, demographics and timing of extinction of moa species, their distributions collapsed and converged in the same areas in the North and South Islands of New Zealand.”
This recent discovery, published in Nature Ecology & Evolutionfound that these moa graveyards are located in the same isolated, cold, mountainous environments that today host many of the last populations of New Zealand’s most endangered flightless birds. These include Mount Aspiring in the South Island and the Ruahine Range in the North Island.
“Moa populations are likely to have first disappeared from the higher quality lowland habitats that Polynesian colonisers preferred, and rates of population decline slow with altitude and distance travelled inland,” said lead author Dr Sean Tomlinson from the University of Adelaide.
“By identifying the last remaining populations of moa and comparing them to the distributions of current flightless birds in New Zealand, we found that these last remaining refugia are home to many of the current persistent populations of takahe, weka and spotted kiwi.”
“Furthermore, these ancient moa refuges overlap with the last continental populations of the kakapo, a critically endangered species.“.
Although the factors driving recent declines in New Zealand’s native flightless birds are different from those driving past moa extinctions, this research shows that their spatial dynamics remain similar.
“The key commonality between past and present refuges is not that they are optimal habitats for flightless birds, but they remain the last and least affected by humanity,” said author Dr Jamie Wood, also of the University of Adelaide’s Environment Institute.
Like previous waves of Polynesian expansion, European habitat conversion in New Zealand and the spread of the animals they brought was directional, moving from lowland sites toward the less hospitable, colder, mountainous regions.”
This new research shows that the ghosts of past species can provide invaluable information for conservation efforts targeting New Zealand’s current flightless birds, highlighting the immense importance of protecting remote and wild places.
It also provides an important new method for understanding past extinctions on islands where fossil and archaeological data are limited, which is the case for most Pacific islands.
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