Research


Conservation and restoration of Mauritian plant communities using an analogue of extinct tortoises, the giant Aldabra tortoise

A PhD study by Christine Griffiths.

Supervised by Stephen Harris, Christine Müller (University of Zürich) and Carl Jones (Mauritian Wildlife Foundation).


photo of giant tortoise
© Mammal Research Unit
Photo by Christine Griffiths

The biodiversity of the Indian Ocean Mascarene archipelago (Mauritius, Rodrigues and La Réunion), like that of many small islands, has a history of severe degradation: only about 2% of Mauritius is covered to some degree with native forests and most of the endemic birds and reptiles are extinct or highly endangered. The integrity of these remaining ecosystems continues to be further threatened by the loss or modification of plant-animal interactions, essential for the functioning of the original ecosystems.

The only large endemic herbivores, the two extinct Mauritian giant tortoises (Geochelone inepta, G. triserrata), were an important component of the lowland ecosystem, which was characterised by palm savannah communities, and which is currently only found on the offshore islets of Round Island, Gunners Quoin and Ile aux Aigrettes. These islands are of major conservation value; their palm savannah ecosystems harbour eight reptile species, five of which are found only on Round Island. Giant tortoises, by virtue of their great abundance , are believed to have been responsible for the preservation and integrity of these ecosystems. However, today the future of palm savannah communities is in question. We will investigate whether the introduction of the Aldabran giant tortoise (Geochelone gigantea) will help restore important trophic interactions, thereby facilitating the management and restoration of islet palm savannah ecosystems.

This project will be a major step towards highlighting the potential use of analogue species to assist in the functioning of restored ecosystems and the necessity of gaining a greater understanding of the complex interactions in communities in order to adopt holistic approaches to conservation management.

Publications

Hansen, D.M., Donlan, C.J., Griffiths, C.J. & Campbell, K.J. (2010) Ecological history and latent conservation potential: large and giant tortoises as a model for taxon substitutions. Ecography, in press.

Griffiths, C.J. & Harris, S. (2010) Experimenting with taxon substitutes may prevent secondary extinctions. Conservation Biology, 24, 645-646.

Griffiths, C.J., Jones, C.G., Hansen, D.M., Puttoo, M., Tatayah, R.V., Müller, C.B. & Harris, S. (2010) The use of extant non-indigenous tortoises as a restoration tool to replace extinct ecosystem engineers. Restoration Ecology, 18, 1-7.

Contact details

Christine Griffiths
Mammal Research Unit
School of Biological Sciences
University of Bristol
Woodland Road
Bristol BS8 1UG, U.K.

Telephone: 0117 9287593
Email: Christine Griffiths