Evidence for ecologically significant changes in climate during the post-glacial period in New Zealand: Climate evidence from sea-level fluctuations
- N.Z. Geological Survey, D.S.I.R., Otahuhu
The ecological changes that result from coastal changes brought about by sea-level fluctuations will not be discussed. Some of these are reasonably self evident, for example the severance of once continuous land into islands during rising sea level. On the other hand, the part played by sea-level change in the production of coastal dunes is not so clear. Such changes together with alterations in coastal currents may be ecologically important but they affect only small coastal areas.
It is generally agreed that sea level has been at least 200-300 ft. lower and higher than the present at different times during the Quaternary, and that these large eustatic changes have been due to major advances and retreats of ice sheets. For example, during glaciation much water, normally returned to the oceans, is locked on land as ice and as a result sea level falls. As we are discussing postglacial climatic changes within New Zealand the major changes in sea level are less important than the superimposed minor changes. Do these have any significant meaning for local climatic changes? First of all we must examine the reliability of the postglacial sea levels.