About 11,000 years ago , the last Ice Age end and humans begin to spread out to all corners of the globe . briefly thereafter , the world ’s megafauna go extinct . So was it mood or human beings that killed the last megafauna ?
To work out a question like this , the ideal test slip would be one where the emergence of man as the region ’s apex predator happened at a wholly different time than when the climate changed . That ’s why New Zealand , which remained completely isolated from human until the first Polynesian settler arrived roughly 800 eld ago , is such a potentially entrancing test case .
Because of the island ’ complete closing off from the rest of the Earth — for its size , New Zealand is probably the most remote habitable landmass on the satellite — New Zealand produce an ecosystem unlike any other . Before the Maori arrive bringing with animals like pigs and cad , the only mammals native to New Zealand were three species of at-bat . All the bionomic niche normally fill by turgid mammal were instead filled by every bit gigantic hoot , with the 10 - ft marvelous moa emerging as New Zealand ’s great skimming beast .
Much like the bison in the nineteenth hundred American west , the reaching of human colonists quickly led to overhunting of the moa , with the various subspecies dying out likely at least a century before the arrival of the first European explorers . What ’s unique about this fussy megafauna quenching is that it occured about 500 to 700 years ago , at a distributor point when the satellite ’s climate was more or less stable . That gives scientist a unequalled hazard to canvas how the moa dealt with earlier climate change independent of human interference , as Australia - based research Dr. Nic Rawlence explains :
“ Until now it has been hard to mold how megafauna responded to environmental change over the past 50,000 years , because human arrival and climate variety occurred at the same time in many parts of the existence . Using ancient DNA , radiocarbon date and stable dietetical isotope depth psychology , we have been able to show that before mankind get , moa mitigated the effects of climate change by give chase their preferred home ground as it enlarge , contracted and switch during warming and cool events . Moa were not in serious downslope before human arrived , as has been previously suggested , but had comparatively static population sizes . The overpowering evidence suggests that the extinction of moa pass due to overhunting and habitat death , at a fourth dimension of relative climatical stableness . ”
While it ’s hard to say how applicable the character of the moa is to that of their more ancient megafauna counterparts elsewhere , they are probably the well grounds that ancient humans most definitely could labour a species to extinction regardless of mood variety . Whether that intend homo are actually responsible for , say , the defunctness of the woolly mammoth is still an open question , but this data would suggest that megafauna had the capacity to weather massive climate fluctuation . clime change in and of itself was almost certainly not a death sentence . As fellow research worker Jamie Wood puts it :
[ The results ] show that reach shifts and minor universe fluctuation observable in the fogey and genetic criminal record are a rude reception to environmental alteration and do not needfully direct to extinction . ”
Check out theUniversity of Adelaide websitefor more .
Original theme atQuaternary Science Reviews . Images byghewgillandTakveron Flickr .
BiologyClimate changemass extinctionScience
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