Australia has more native bird species than almost anywhere else. What led to this explosion of diversity?
Source: The Conversation | By Stephen Garnett | November 13, 2023 6.15am AEDT
When you went out today, did you see any birds? A galah perhaps, or a crow?
If you did, there’s a decent chance the bird you saw lives nowhere but Australia. Out of about 850 species found in Australia, 45% are “endemic”, which means they’re unique to Australia. The only other country with more endemic species is Indonesia.
Thanks to their wings, birds are the world’s greatest travellers. So why is it that such a high proportion of Australian birds aren’t found anywhere else?
Climate rules
The story starts more than 45 million years ago, when Australia first split from Antarctica and started to head north. It was the events that occurred during this trip – particularly in relation to our climate – that led to the diversity in Australia’s birds today.
When it first set out, Australia was covered in lush rainforest. As it drifted, however, the climate became much drier. Our distinctive flora of grasslands and eucalypt woodlands started to spread across the continent.
But this drying trend wasn’t consistent. Particularly in the last million years, dry periods associated with the ice ages alternated with wetter times, such as the Holocene epoch – which is what we’ve had for the past 10,000 or so years.
But the climate didn’t just vary over thousands of years. It also varied, as we know too well, from year to year. Australia has long been the land of long droughts, sometimes lasting decades, interspersed with flooding rains.
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Gabrielle
[City] NSW
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