They discover two waves of extinction from 23,000 years ago and 11,000

An investigation reveals that 23,000 years ago a wave of extinction of animal species was unleashed and 11,000 years ago, another.

The finding has been possible thanks to clues found in fungal spores found in ancient animal feces. Both waves of extinction mainly affected prehistoric animals with a body weight greater than 45 kilograms, in the Colombian Andes region.

The spores of coprophilic fungi are consumed by large herbivores, such as those of the prehistoric megafauna, and then germinate in their feces, so their presence in sediment samples shows that these animals lived in a specific place and time.

The study, led by Colombians based at the University of Exeter in the UK, found that the megafauna became locally extinct in the Monquentiva Swamp around 23,000 years ago, and again around 11,000 years ago, with major repercussions on ecosystems.

The study used samples from the Pantano de Monquentiva peat bog, located about 60 kilometers from Bogotá in the eastern cordillera. The study is the first of its kind conducted in Colombia.

For the study, samples from the Monquentiva swamp area were used. (Photo: F. Pym 2022)

With the current biodiversity crisis, these findings underscore how the disappearance of megafauna could once again transform the ecosystems that support wildlife and humans.

“We know that large animals, such as elephants, play a vital role in regulating ecosystems, for example eating and trampling vegetation,” explains Dr Dunia H. Urrego, from the University of Exeter and a graduate of the University National of Colombia, Medellín Headquarters.

“By analyzing samples of dung fungal spores, as well as fossil pollen and charcoal, we were able to investigate the extinction of these herbivores and the consequences of this extinction for plant abundance and fire occurrence.

“We found that the Monquentiva ecosystem changed drastically when the Megafauna disappeared; the abundance of some plant species increased and there were more forest fires.”

“Analysis of fungal spores does not allow us to determine which animal species were present, but species known to have roamed Colombia in this period include the giant armadillo (Glyptodon sp.) and the giant ground sloth (Megatherium sp.) , similar to the current sloths but that could measure up to six meters in height.”

The findings show that abundant megafauna existed in the area for thousands of years, disappearing completely around 23,000 years ago.

Some 5,000 years later, megafauna returned to live in the area, albeit in smaller numbers, before another wave of extinction around 11,000 years ago reduced it to near zero.

The cause of these local extinctions is unknown, but climate changes and hunting by humans are two possibilities. Other researchers have even suggested that a meteorite impact could be the cause.

“After the disappearance of the megafauna, the vegetation in Monquentiva underwent a transition, with more woody and edible plants (those preferred by grazing animals) and the loss of plants that depend on animals to disperse their seeds,” explains Felix Pym. , co-author of the study and a Physics Geography Research Masters student at the University of Exeter.

“Forest fires increased after megafaunal extinctions, presumably because flammable plants were no longer eaten or trampled.”

“Overall, our findings show that this habitat was highly sensitive to declines in its megafauna populations.”

Another of the study’s conclusions is that, given the current biodiversity crisis, conservation efforts and management of wilderness areas must take into account the effects of the decline in local herbivores on the dispersal of certain plant species, the occurrence of fires and the possible loss of ecosystem services (the benefits that humans obtain from nature).

The study is titled “The timing and ecological consequences of Pleistocene megafaunal decline in the eastern Andes of Colombia”. And it has been published in the academic journal Quaternary Research. (Source: University of Exeter)