First empirical evidence to show that rewilding can work

Resurrecting Extinct Interactions with Extant Substitutes

Christine J. Griffiths, Dennis M. Hansen,Carl G. Jones,Nicolas Zuël,Stephen Harris

Current Biology, 21 April 2011

In this paper the researchers say intentional introduction of exotic species is a sure shot way  to fulfill key functions in ecosystems following the loss of recently extinct species. This is the first clear cut evidence to substantiate the hypothesis that exotic species can deliver ecosystem functions of extinct species.

The scene of action is Ile aux Aigrettes, a 25-hectare island off the coast of Mauritius. Ebony ( Diospyros egrettarum )in the island is now critically endangered following intensive logging for firewood. Even though logging was stopped thirty years ago regeneration was far from satisfactory and was taking a nosedive. With the extinction of the island's native giant tortoises, there were no large fruit-eating animals left to disperse the seeds of these critically-endangered trees.

Giant Aldabra tortoises,(Aldabrachelys gigantea) were introduced to reverse the process. The introduced Aldabra tortoises ingested the large fruits and dispersed the ebony seeds. The process of passing through a tortoise's gut gave a further fillip to seed germination. Establishment of new ebony seedlings in the heavily logged parts of the island came in rapidly.

The authors signs off saying “There is increasing evidence that restoration ecologists should be most concerned with the decline of species interactions, rather than species extinctions per se.”