Plant dispersal by the Aldabran giant tortoise, Geochelone gigantea (Schweigger)
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A total of 28 species of grasses, herbs, and woody plants germinated from faeces of Aldabran giant tortoises. It seems likely that all members of the land flora can be ingested by tortoises and so may be dispersed by them over short distances.
The tortoises are thought to have derived from a Madagascan stock and reached Aldabra from time to time by transmarine migration until the extermination of the Madagascan tortoises about 1100 years ago. The time taken by a tortoise to void its last meal is much longer than that required to float, at present current speeds, from Madagascar to Aldabra. If neither of these parameters have changed since the tortoise migrations to Aldabra, the tortoises may have been responsible for the introduction of plant species to Aldabra.
KeywordsMigration Plant Species Germinate Short Distance Woody Plant
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- Arnold, E.N.: Indian Ocean giant tortoises: their systematics and island adaptations. Phil. Trans. Roy. Soc. Lond. B (in press)Google Scholar
- Bourn, D.M., Coe, M.J.: The size, structure and distribution of the giant tortoise population. Phil. Trans. Roy. Soc. Lond. B 282 139–175 (1978)Google Scholar
- Braithwaite, C.J.R., Taylor, J.D., Kennedy, W.J.: The evolution of an atoll: the depositional and erosional history of Aldabra. Phil. Trans. Roy. Soc. Lond. B 266, 307–340 (1973)Google Scholar
- Coe, M., Bourn, D., Swingland, I.R.: The biomass, production and carrying capacity of giant tortoises on Aldabra. Phil. Trans. Roy. Soc. Lond. B (in press)Google Scholar
- Frazier, J.G.: Behavioural and ecological observations on giant tortoises on Aldabra Atoll. Oxford, unpublished doctoral thesis (1971)Google Scholar
- Grubb, P.: The growth, ecology and population structure of giant tortoises on Aldabra. Phil. Trans. Roy. Soc. Lond. B 260, 327–372 (1971)Google Scholar
- MacFarland, C.: Giant tortoises, goliaths of the Galapagos. The Natn. Geog. Mag. 142, 632–649 (1972)Google Scholar
- Porter, D.M.: Geography and dispersal of Galapagos islands vascular plants. Nature (Lond.) 264, 745–746 (1976)Google Scholar
- Renvoize, S.A.: The origin and distribution of the flora of Aldabra. Phil. Trans. Roy. Soc. Lond. B 260, 227–236 (1971)Google Scholar
- Renvoize, S.A.: A floristic analysis of the western Indian Ocean coral islands. Kew Bull. 30, 133–152 (1975)Google Scholar
- Rick, C.M., Bowman, R.I.: Galapagos tomatoes and tortoises. Evolution 15, 407–417 (1961)Google Scholar
- Ridley, H.N.: The dispersal of plants throughout the world. Ashford, Kent: Reeve 1930Google Scholar
- Rodhouse, P., Barling, R.W.A., Clark, W.I.C., Kinmonth, A-L., Mark, E.M., Roberts, D., Armitage, L.E., Austin, P.R., Baldwin, S.P., Bellairs, A.d'A., Nightingale, P.J.: The feeding and ranging behaviour of Galapagos giant tortoises (Geochelone elephantopus). J. Zool. Lond. 176, 297–310 (1975)Google Scholar
- Stebbins, G.L.: Variation and evolution in plants. New York: Columbia University Press 1950Google Scholar
- Stoddart, D.R.: Place names of Aldabra. Phil. Trans. Roy. Soc. Lond. B 260, 631–632 (1971)Google Scholar
- Van der Pijl, L.: Principles of dispersal in higher plants, 2nd ed. Berlin-Heidelberg-New York: Springer 1972Google Scholar
- Wickens, G.E.: Speculations on seed dispersal and the flora of the Aldabra Archipelago. Phil. Trans. Roy. Soc. Lond. B (in press)Google Scholar