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Jean M
07-30-2017, 09:43 PM
Nicolas J. Rawlence, et al., Ancient DNA and morphometric analysis reveal extinction and replacement of New Zealand's unique black swans, Proceedings of the Royal Society B, Volume 284, issue 1859


Prehistoric human impacts on megafaunal populations have dramatically reshaped ecosystems worldwide. However, the effects of human exploitation on smaller species, such as anatids (ducks, geese, and swans) are less clear. In this study we apply ancient DNA and osteological approaches to reassess the history of Australasia's iconic black swans (Cygnus atratus) including the palaeo-behaviour of prehistoric populations. Our study shows that at the time of human colonization, New Zealand housed a genetically, morphologically, and potentially ecologically distinct swan lineage (C. sumnerensis, Poūwa), divergent from modern (Australian) C. atratus. Morphological analyses indicate C. sumnerensis exhibited classic signs of the ‘island rule’ effect, being larger, and likely flight-reduced compared to C. atratus. Our research reveals sudden extinction and replacement events within this anatid species complex, coinciding with recent human colonization of New Zealand. This research highlights the role of anthropogenic processes in rapidly reshaping island ecosystems and raises new questions for avian conservation, ecosystem re-wilding, and de-extinction.

Saetro
07-31-2017, 12:01 AM
Nicolas J. Rawlence, et al., Ancient DNA and morphometric analysis reveal extinction and replacement of New Zealand's unique black swans, Proceedings of the Royal Society B, Volume 284, issue 1859

Sad but true.
We can often infer the arrival of humans when a species declines substantially or completely, or in other cases, when new species arrive.
Adverse climate changes need to be taken into account, of course.
But generally, changes in species "go wher'ere the hand of man has trod", to quote a mixed metaphor.