Summary
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.
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Hnatiuk, S.H. Plant dispersal by the Aldabran giant tortoise, Geochelone gigantea (Schweigger). Oecologia 36, 345–350 (1978). https://doi.org/10.1007/BF00348060
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DOI: https://doi.org/10.1007/BF00348060