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Climate change and geological transformations have influenced the formation of New Zealand's avifauna, contributing to the constant invasion of new species.
During the Ice Age, the landscape of Aotearoa underwent radical changes, with dense forests giving way to open grassland and shrub ecosystems. Researchers from the University of Otago sought to determine which birds are descendants of ancient native species and which are the result of later colonisation. Using mitogenome data, they found that a number of modern birds, such as the putangitangi paradise duck and the New Zealand hemp-winged duck, arrived from Australia at the start of the Ice Age.
Dr Pascal Lubbe stresses that immigrants are not alien to New Zealand's natural history, but on the contrary - repeated invasions are a key element of its biodiversity.
. A study published in the journal Molecular ecology, analyses the evolutionary relationships between Aotearoa birds and their overseas relatives.
Previous work focused mostly on the species level, but the new approach explores the origins of almost all of the country's endemic species.
In the context of current global warming, these results are important for predicting future changes in biodiversity. The reduction of New Zealand's forest cover is already contributing to the invasion of Australian species such as swallows and sedge warblers. “If the trend of forest loss continues, even more bird species from Australia will migrate here, posing biosecurity risks.”, warns Dr. Lubbe. The extinction of endemic species can leave ecological niches empty, which will contribute to further invasions of new birds and changes in local ecosystems.
