Early Holocene plant remains from the Cromwell Gorge, Central Otago, New Zealand

Central Otago is one of the driest parts of New Zealand, and much of the natural vegetation of the region was lost to fires following human settlement in the 13th Century AD. Plant macrofossil and pollen records have provided detailed insights into the vegetation communities that existed in Central Otago’s lowlands at the time of human settlement, but relatively little is known about the regional vegetation patterns prior to ~3000 years ago. Here, we present analyses of pollen and plant macrofossil assemblages from a buried cave deposit in the Cromwell Gorge which dates to the early Holocene (~11 700–8300 years ago), a time when the climate was significantly warmer than during the late Holocene. The results show that at this time the local vegetation community consisted of low open scrubland or woodland, very similar to that found there during the late Holocene. Rare tall forest tree pollen was probably derived from distant sources in Southland or coastal Otago, where forest was spreading at this time. The absence of evidence for tree species that were regionally dominant during the late Holocene (Phyllocladus alpinus, Kunzea serotina and Podocarpus hallii), and the abundance of low-growing shrubs, indicates that during the early Holocene the interior valleys of Central Otago may have experienced a climate substantially drier than present.