Drift Seeds and Fruit on Raine Island, Northern Great Barrier Reef, Australia

• Published in: Journal of biogeography Vol. 17; no. 1; pp. 19 - 24
• Main Author: Hacker, J. B.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Scientific Publications 01-01-1990; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Beaches; Biological and medical sciences; Coral reefs; Dispersal, Disturbance, and Density; Fruits; Fundamental and applied biological sciences. Psychology; Germination; Keys; Marine; Plants; Reefs; Sea water ecosystems; Seeds; Synecology; Vegetation; Viability; Littoral zone; Floristic composition; Seeds; Fruit; Coral reef; Island; Survival; Oceania; Sea current; Dissemination; Niche; Australia; Great Barrier Reef
• ISSN: 0305-0270; 1365-2699
• DOI: 10.2307/2845184

The vegetation of Raine Island, a sand cay of the northern Great Barrier Reef and the drift seeds and fruit on its beach and along its strand-line were studied during July-August 1987. Seeds and fruit were identified and tested for viability by germination following scarification or using tetrazolium. A total of twelve species of vascular plant was found growing on the island. Ten of these had been noted on previous expeditions; Ipomoea macrantha Remer & Schultes was last recorded in 1846. Dactyloctenium aegyptium (L.) Beauv. and Cleome viscosa L. are new records for the island. Three distict ecological niches were identified which differed in species composition. Seed/fruit density was 710 per 100 m beach length. Overall, thirty-seven species of seeds and fruit were collected on the beach and strand-line of which thirty-two were identified with some certainty. Sixteen species included viable individuals. On a percentage basis the highest level of viability was in Lebuminosae, Convolvulaceae and Pandanaceae. The only drift seed of a species present as living plants on the island was Ipomoea macrantha. Most drift seed and fruit were from species common to both Papua New Guinea and northern Australia. However, seeds of Pangium edule Reinw., not known to occur in Australia but occurring in Papua New Guinea, had presumasbly floated the c. 300 km from that country. This hypothesis is suported by the existence of a southerly-flowing ocean current immediately to the east of the northern Great Barrier Reef.