Fine resolution palynology of Gibson’s Swamp, central North Island, New Zealand, since c. 13,000 BP

Abstract

Fine resolution pollen analysis shows that the late-glacial (c. 13 000-10 700 B.P.) vegetation of the Ohakune-Horopito area was dominated by Prumnopitys taxifolia, indicating a cooler and probably drier climate than the present. Around 10 700 B.P., Dacrydium cupressinum replaced Prumnopitys taxifolia as the forest dominant, and tree ferns and hardwood trees expanded, suggesting change to warmer or wetter conditions. Around 5800-6300 B.P., Dacrydium cupressinum and tree ferns declined, Prumnopitys taxifolia regained some of its former dominance, and hardwood species continued to expand, suggesting a change to more variable conditions.

Immediately following the Taupo Tephra eruption of 1718 BP, Libocedrus bidwillii expanded at Gibson's Swamp. The eruption may have facilitated a regional expansion of this species which was apparently already underway as a result of a climate change to stormier and cooler conditions prior to the eruption. Extensive logging for podocarps in Ohakune-Horopito after AD 1850 resulted in an increase in the abundance of Weinmannia racemosa.

Keywords

Palynology, late glacial, Holocene, Taupo Tephra eruption, Libocedrus bidwillii, central North Island.