New Zealand’s Endangered Birds find refuge in ancient Moa habitats

Research shows that New Zealand’s endangered flightless birds inhabit regions once populated by the extinct moa, highlighting the value of conserving these areas of minimal human impact and introducing a new method for studying island extinctions.

Researchers have found that New Zealand’s endangered flightless birds are taking refuge in the same areas as six species of moa were last seen before their disappearance.

An international team of researchers, led by scientists from the University of Adelaide, used fossils and computer modeling to make the discovery, shedding light on a mystery with significant conservation benefits.

“Our research overcame past logistical challenges to track the population dynamics of six moa species at resolutions not previously considered possible,” said senior author Associate Professor Damien Fordham, from the University of Adelaide’s Institute of the Environment. .

“We did this by combining sophisticated computational models with extensive fossil records, paleoclimate information and innovative reconstructions of human colonization and expansion across New Zealand.

“Our research shows that despite large differences in the ecology, demography and timing of extinction of moa species, their distributions collapsed and converged in the same areas on the North and South Islands of New Zealand.”

This latest discovery, published in Nature Ecology and Evolution, found that these moa graveyards are in the same isolated, cold, mountainous environments that today house many of the last populations of New Zealand’s most threatened flightless birds. These include Mount Aspiring in the South Island and the Ruahine Range in the North Island.

Last shelters of the Moa and modern flightless birds

“Populations of moa likely disappeared first from the lower, higher quality habitats preferred by Polynesian colonists, with rates of population decline decreasing with altitude and distance traveled inland,” said the lead author. Dr. Sean Tomlinson, from the University of Adelaide.

“By pinpointing recent populations of moa and comparing them to the distributions of New Zealand’s living flightless birds, we found that these last havens harbor many of today’s persistent populations of takahē, skinny kiwi and with big spots”.

“Furthermore, these ancient refugia for moa overlap with recent mainland populations of critically endangered kākāpō.”

Although the recent drivers of the decline of New Zealand’s native flightless birds are different from those that caused the moa’s ancient extinction, this research shows that their spatial dynamics remain similar.

“The main commonality between past and present refuges is not that they are optimal habitats for flightless birds, but that they continue to be the last and least affected by humanity,” said author Dr Jamie Wood, also of the Environment Institute. of the University of Adelaide.

Like earlier waves of Polynesian expansion, habitat conversion by Europeans across New Zealand and the spread of animals they brought was directional, progressing from lowland areas to less hospitable, cold, mountainous regions.

This new study shows that ghosts of past species can provide invaluable insights into conservation efforts aimed at New Zealand’s living flightless birds, highlighting the critical importance of protecting remote and wild places.

It also provides an important new method for understanding past extinctions on islands where fossil and archaeological records are limited, which is the case for most Pacific islands.

Reference: “Ecological dynamics of moa extinctions reveal a convergent refuge that today harbors flightless birds” by Sean Tomlinson, Mark V. Lomolino, Jamie R. Wood, Atholl Anderson, Stuart C. Brown, Sean Haythorne, George LW Perry, Janet M. Wilmshurst, Jeremy J. Austin and Damien A. Fordham, 24 July 2024, Nature Ecology and Evolution.
DOI: 10.1038/s41559-024-02449-x

The study was funded by the Australian Research Council.