Legacy of supervolcanic eruptions on population genetic structure of brown kiwi

Supervolcanoes are volcanoes capable of mega-colossal eruptions that emit more than 1,000 km(3) of ash and other particles.(1) The earth's most recent mega-colossal eruption was the Oruanui eruption of the Taupo supervolcano 25,580 years before present (YBP) on the central North Island of New Zealand.(2) This eruption blanketed major swaths of the North Island in thick layers of ash and igneous rock,(2,3) devastating habitats and likely causing widespread population extinctions.(4-)7 An additional devastating super-colossal eruption (>100 km(3)) of the Taupo supervolcano occurred approximately 1,690 YBP.(8) The impacts of such massive but ephemeral natural disasters on contemporary population genetic structure remain underexplored. Here, we combined data for 4,951 SNPs with spatially explicit demographic and coalescent models within an approximate Bayesian computation framework to test the drivers of genetic structure in brown kiwi (Apteryx mantelli). Our results strongly support the importance of eruptions of the Taupo supervolcano in restructuring preexisting geographic patterns of population differentiation and genetic diversity. Range shifts due to climatic oscillations-a frequent explanation for genetic structure(9)-are insufficient to fully explain the empirical data. Meanwhile, recent range contraction and fragmentation due to historically documented anthropogenic habitat alteration adds no explanatory power to our models. Our results support a major role for cycles of destruction and post-volcanic recolonization in restructuring the population genomic landscape of brown kiwi and highlight how ancient and ephemeral mega-disasters may leave a lasting legacy on patterns of intraspecific genetic variation.

Automated summary

Supervolcanoes are capable of emitting mega-colossal eruptions, with the most recent example being the Oruanui eruption of the Taupo supervolcano in New Zealand. These eruptions have significant impacts on habitats and population extinctions. This study focuses on the genetic structure of brown kiwi and finds that the eruptions of the Taupo supervolcano played a major role in reshaping the population differentiation and genetic diversity of the species.