Ko'olau Mountain Range on Oahu -- The Third Largest of the Hawaiian Islands. (image) University of Göttingen Share Print E-Mail Caption Ko'olau Mountain range on Oahu -- the third largest of the Hawaiian Islands. Researchers investigated the effects on biodiversity of introduced species and island age. Credit William Weaver Usage Restrictions Credti: William Weaver Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.