Substrata specificity and episodic catastrophe: contstraints on the insular plant geography of Suwarrow atoll, Northern Cook Islands

Coral atolls are natural laboratories within which to examine ecological processes (Sachet, 1967; Lee, 1984). They are often isolated, in some cases little disturbed, and have a geologically recent history of terrestrial plant colonisation. Reef islands around the rim of most atolls are Holocene in age. They are composed of biogenic skeletal sediments and have developed since reef growth caught up with sea level which stabilized after post-glacial sea-level rise. Plant colonisation of most of these islands must have occurred over a period of no more than 6000 years.