Climate

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.

There are at least three hypotheses to account for the abundance of divaricating shrubs in New Zealand: 1) Ratites in the form of 11 species of moa, led to divarication for browse protection (Greenwood and Atkinson, 1977); 2) Divarication evolved as a microclimatic shield (McGlone and Webb, 1981); 3) Divarication evolved to aid leaves in light harvesting (Kelly, 1994). In Patagonia before human arrival, there were browsing mammals in addition to the ratite rhea.

Meteorological data from stations around and within the Kaimai Ranges and data from temporary sites are used to characterise the climate of the ranges. Lowland climate is warm temperate with ample rainfall but the upland region is cooler, wetter and frequently enveloped in fog. Frequent fog plays an important part in the climate of upland regions. By modifying light, moisture and temperature regimes fog may be a significant determinant of plant associations and may severely restrict growth.

Understanding the evolutionary history and biogeography of the New Zealand alpine flora has been impeded by the lack of an integrated model of geomorphology and climate events during the Late Miocene, Pliocene and Pleistocene. A new geobiological model is presented that integrates rock uplift age, rate of uplift and the resulting summit elevations in the Southern Alps (South Island) during the last 8.0 million years with a climate template using the natural gamma radiation pattern from the eastern South Island Ocean Drilling Program Site 1119 that covers the past 3.9 million years.