Conroy, K.J., Baker, A.G., Jones, V.J., van Hardenbroek, M., Hopla, E.J., Collier, R., Lister, A.M., Edwards, M.E. (2020) Tracking late-Quaternary extinctions in interior Alaska using megaherbivore bone remains and dung fungal spores. Quaternary Research. DOI: https://doi.org/10.1017/qua.2020.19
Article first published online: 28 April 2020
Read article by following this link, taking you to the Cambridge University Press Core collection.
This research is considerably questioning some of the accepted wisdoms surrounding late-Quaternary extinctions of megaherbivore. While research so far has associated the extinctions with dramatic ecosystem changes and crashes in abundance in all megaherbivores species – including those species that survived – here, we show that it is not systematically the case, by providing the counterexample of interior Alaska.
There is an increasing interest in of the late-Quaternary extinction, to understand their consequences for ecosystems function. Understanding these consequences help us guide rewilding initiatives and harness the potential of large vertebrate as ecosystem engineers in a more creative way, as explained in this article I have written for The Conversation.
Quaternary Research article abstract:
“One major challenge in the study of late-Quaternary extinctions (LQEs) is providing better estimates of past megafauna abundance. To show how megaherbivore population size varied before and after the last extinctions in interior Alaska, we use both a database of radiocarbon-dated bone remains (spanning 25-0 ka) and spores of the obligate dung fungus, Sporormiella, recovered from radiocarbon-dated lake-sediment cores (spanning 17-0 ka).
Bone fossils show that the last stage of LQEs in the region occurred at about 13 ka ago, but the number of megaherbivore bones remains high into the Holocene. Sporormiella abundance also remains high into the Holocene and does not decrease with major vegetation changes recorded by arboreal pollen percentages. At two sites, the interpretation of Sporormiella was enhanced by additional dung fungal spore types (e.g. Sordaria).
In contrast to many sites where the last stage of LQEs is marked by a sharp decline in Sporormiella abundance, in interior Alaska our results indicate the continuance of megaherbivore abundance, albeit with a major taxonomic turnover (including Mammuthus and Equus extinction) from predominantly grazing to browsing dietary guilds.
This new and robust evidence implies that regional LQEs were not systematically associated with crashes of overall megaherbivore abundance.”