With some exceptions, experts say, large-scale extinction of big animals generally coincided with the arrival of early modern humans in places where they had never been.
Given large-scale extinctions on islands, it is important to understand whether introduced birds serve as functional replacements or whether the absence of native frugivores alters plant communities.
An alternative or complementary scenario is that the Early Eocene Climatic Optimum 51-53 Ma [ 40, 41], when mean global temperatures reached ~12°C higher than today's level, would have caused a wave of large-scale extinction and thus left many empty ecological niches available for orchid diversification.
For full explication, see text Fig. 11 Large-scale extinction and evolutionary recovery patterns in biological evolution.
Repeated outbreaks of mange (scab) have led to large-scale extinctions.
A20 The Cost of Extinctions Researchers said it takes 10 million years to recover from large-scale extinctions, a finding with implications for human activity that causes extinctions great and small.
But in an entirely unexpected finding that has gotten the attention of both paleontologists and conservationists, researchers reported today that it takes a long time to recover from these large-scale extinctions -- around 10 million years -- and more intriguing, the recovery time appears to be the same, whether the original destruction was one of the grander or one of the more minor events.
For years researchers have blamed quick, massive eruptions like this one for numerous large-scale extinctions.
The episodes of expansion are highly correlated with episodes of regional and global climate change, so the taxon pulse may represent a general response to climate change, including large-scale extinctions.
"This is a relatively small release, however it is the beginning of a large scale approach to prevent the extinction of this species.
Other sudden systemic changes could lie ahead – such as large scale collapse of the Antarctic and Greenland ice sheets, collapse of part of the Gulf Stream, loss of the Amazon rain forest, die-off of coral reefs, and mass extinctions.
