Study Reveals Ancient Koala Population Crash Linked to Glacial Cycles
Koala numbers crashed across Australia 100,000 years ago. Global glacial cycles are likely to blame
The Conversation
Image: The Conversation
A recent study indicates that koalas in Australia faced a significant population decline approximately 100,000 years ago, likely due to global glacial cycles rather than human activity. This research alters previous understandings of koala genetics and their evolutionary history.
- 01Koalas experienced a population crash around 100,000 years ago, predating human arrival in Australia.
- 02The study determined a mutation rate of 25 mutations per offspring, aiding in historical population estimates.
- 03Environmental changes during the Pleistocene, including glacial cycles, led to habitat loss for koalas.
- 04The western koala population went extinct around 28,000 years ago, while eastern populations survived and diversified.
- 05Modern koalas are again facing declines due to habitat loss, disease, and other threats, but genetic diversity remains intact for recovery.
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A new study published in the journal Molecular Biology and Evolution reveals that koalas in Australia underwent a significant population decline approximately 100,000 years ago, contradicting earlier beliefs that linked their decline to human activities. Researchers sequenced the genomes of 12 koalas to establish a mutation rate, which allowed them to trace population changes over time. The findings indicate that the decline coincided with intense environmental changes during the Pleistocene, notably global glacial cycles that shrank suitable habitats and separated koala populations. While the ancient decline was driven by natural climatic shifts, modern koalas are facing similar challenges due to habitat destruction, disease, and other human-related threats. Despite these pressures, many populations still possess genetic diversity, which may aid in their recovery.
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Koalas are facing renewed population declines due to habitat loss and other threats, impacting biodiversity in Australia.
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