Related Experiment Video
Updated: Dec 21, 2025
09:11
Cortisol Measurement in Koala Phascolarctos cinereus Fur
Published on: August 23, 2019
11.0K
Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration
Scott A Hocknull1,2, Richard Lewis3, Lee J Arnold3
1Geosciences, Queensland Museum, 122 Gerler Rd., Hendra, QLD, 4011, Australia. scott.hocknull@qm.qld.gov.au.
Nature Communications
|May 19, 2020
Summary
Upper Pleistocene megafauna extinctions in Sahul were not human-driven. New fossil evidence suggests extinctions resulted from staggered hydroclimate deterioration and environmental change, not rapid human impact.
Area of Science:
- Paleontology
- Quaternary Science
- Environmental History
Background:
- The extinction of megafauna in Sahul (Australia and New Guinea) during the Upper Pleistocene is poorly understood.
- Existing hypotheses focus on climate or human-driven scenarios, despite limited data for much of the region.
Observation:
- New megafauna fossils from north-eastern Australia date to after 40,100 (±1700) years ago.
- Fossils indicate a sclerophyllous forest environment with diverse megaherbivores and carnivorous reptiles.
- Megafauna species diversity in this region exceeds that of southern sites of similar age.
Findings:
- The findings challenge rapid, continent-wide human-mediated extinction models and proposed extinction timing.
- Megafauna extinctions correlate with regionally varied, long-term hydroclimate decline and environmental shifts.
- Greater species diversity in the north contradicts extinction patterns linked to proposed human migration routes.
Implications:
- This study refutes synchronous human-driven extinction of Sahul's megafauna.
- Environmental factors, specifically hydroclimate changes, played a significant role in megafauna extinctions.
- The research highlights the need for more localized data to understand past extinction events.
Related Concept Videos
01:50Threats to Biodiversity
26.3K
There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species that adapted to the new conditions. In the current geological epoch, the Holocene, there is a sixth extinction event in progress. This mass extinction has been attributed to human activities and is thus provisionally called the Anthropocene. In 2019 the human population reached 7.7 billion people and is projected to comprise 10 billion by...
26.3K
02:31Habitat Fragmentation
20.8K
Habitat fragmentation describes the division of a more extensive, continuous habitat into smaller, discontinuous areas. Human activities such as land conversion, as well as slower geological processes leading to changes in the physical environment, are the two leading causes of habitat fragmentation. The fragmentation process typically follows the same steps: perforation, dissection, fragmentation, shrinkage, and attrition.
20.8K
02:07Conservation of Declining Populations
12.4K
Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.
12.4K
02:04Conservation of Small Populations
16.5K
Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...
16.5K
01:57What is Conservation Biology?
23.8K
Conservation biology is a scientific field that focuses on the preservation of biodiversity in order to protect ecosystems while meeting the needs of the human population. Humans require properly functioning ecosystems to maintain our supply of natural resources, including food, medicines, and building materials.
23.8K
02:26Ecological Disturbance
20.5K
An ecological disturbance is a temporary disruption in the environment resulting from abiotic, biotic, or anthropogenic factors, causing a pronounced change in an ecosystem. The impact of an ecological disturbance, which can depend on its intensity, frequency, and spatial distribution, plays a significant role in shaping the species diversity within the ecosystem.
20.5K