Climate drives uneven distribution of Australian, Asian species: study

CANBERRA, July 7 (Xinhua) — A shifting climate and changing plate tectonics drove the uneven distribution of Australian and Asian species, a research has found.

In a study published on Friday, researchers from the Australian National University (ANU) sought to discover why people won’t find kangaroos, koalas and other Aussie marsupials in Indonesia, but they will find many groups of animals that originated in Asia, such as goannas, rodents and kookaburras in Australia.

A team of biologists have concluded that a dramatic shift in the Earth’s climate tens of millions of years ago and a “continental collision” were responsible for the asymmetrical distribution.

They found that Asian species were better suited to tolerating varying climatic conditions and were therefore able to adapt better to Australia than Australian species such as kangaroos and koalas could to Asia.

“When Australia drifted away from Antarctica, it opened up this area of Deep Ocean surrounding Antarctica which is now where the Antarctic Circumpolar Current is. This dramatically changed Earth’s climate as a whole; it made the climate much cooler,” said Alex Skeels from ANU in a media release.

“Despite this global cooling, the climate on the Indonesian islands, which organisms used as a gateway to hop to Australia, remained relatively warm, wet and tropical. So Asian fauna were already well adapted and comfortable with these conditions, so that helped them settle in Australia.”

Skeels said this was not the case for the Australian species. They had evolved in a cooler and increasingly drier climate over time and were therefore less successful in gaining a foothold on the tropical islands compared to the creatures migrating from Asia.

The team analyzed a dataset of about 20,000 birds, mammals, reptiles and amphibians to determine which species hopped between Indonesia and Australia, and which ones were able to successfully adapt to their new home.

“Our findings could also inform predictions for animal migration in the future and help us predict which species may be better versed at adapting to new environments, as changes to Earth’s climate continues to impact global biodiversity patterns,” Skeels said.