Ancient poo provides clues to multiple waves of extinction in Colombia

“We know that large animals such as elephants play a vital role in regulating ecosystems, for example, by eating and trampling vegetation,” said Dr. Dunia H. Urrego of Exeter’s Global Systems Institute.

“By analyzing samples of fungal spores, as well as pollen and charcoal, we were able to track the extinction of large animals and the consequences of this extinction for plant abundance and fire activity. We found the Monquentiva ecosystem changed dramatically when large animals disappeared, with different plant species thriving and wildfires increasing,” Urrego added.

Local extinctions are unknown

Megafauna started to repopulate the area approximately 5,000 years later, though probably in lesser numbers, before a second wave of extinction about 11,000 years ago nearly wiped them off. Although these local extinctions' origins are unknown, human hunting and climate change are two hypotheses. Even a meteorite strike has been proposed as a possible explanation by researchers.

“After the megafauna vanished, plant species at Monquentiva transitioned, with more woody and palatable plants (those favored by grazing animals), and the loss of plants that depend on seed dispersal by animals,” said first author Felix Pym, a Master by Research in Physical Geography student at the University of Exeter.

“Wildfires became more common after the megafauna extinctions – presumably because flammable plants were no longer being eaten or trampled upon.

“Overall, our findings show that this habitat was susceptible to the decline of its megafaunal populations.”

The study was published in Quaternary Research.

Study abstract:

Examining the ecological consequences of the late Quaternary megafaunal extinctions within biodiversity hotspots is crucial for our understanding of the potential consequences of contemporary extinctions. We present the first multi-species record of spores of coprophilous fungi (SCF) from Monquentiva and the high-Andean forests of Colombia to reconstruct Late Pleistocene and Holocene megafaunal abundance. Fossilised pollen and charcoal are used to examine the consequences of megafaunal declines on the surrounding vegetation and fire activity. Our SCF record indicates the presence of Pleistocene megafauna at least since 30,290 BP, with two waves of megafaunal decline at ca. 22,900 BP and 10,990 BP. At Monquentiva, megafaunal decline in the Early Holocene resulted in transitional non-analogue vegetation, loss of some herbivore-dispersed plant taxa, an encroachment of palatable and woody flora, and a rise in fire activity. Differences with other published South-American records suggest that ecological consequences of megafaunal declines were habitat-specific. Overall, we show that ecosystems in the eastern Colombian Cordillera were highly sensitive to the decline of megafaunal populations. Under the current biodiversity crisis, management and conservation efforts must account for the effects of local herbivore declines on plant dispersal, on fire activity, and the potential loss of ecosystem services.