Seychelles Giant Tortoise breeding

231201403

Project grant Nr.

Target species

Granitic Seychelles Giant tortoise

Dipsochelys hololissa & arnoldi

Reptiles, Testudines, Testudinidae

IUCN conservation status:

EW (extinct in the wild)

EDGE status:

N/a

Why engage?

Need / goals

Create a breeding population from two extremely rare species of Giant Tortoises (Dipsochelys/Aldabrachelys hololissa and Dipsochelys/Aldabrachelys arnoldi) which are endemic to the granitic Seychelles.

Conservation action

Programme partner

Programme location

Silhouette, Seychelles

Funding

Date awarded:

$ 19,600 (2001-2011)

15/04/01, 00:00

The species

Range

Habitat

Threats

Population trend

Conservation attention

Conservation need

A number of factors threaten the survival of this super-rare canid. High altitude Afroalpine grasslands are crucial pastureland for the local people’s livestock, and heathlands provide firewood. Increasing livestock populations may be already exerting unsustainable pressure, degrading the Afroalpine ecosystem in many places and reducing the wolves' prey (rodents). Already, 60% of former Ethiopian wolf habitat (i.e. land above the tree-line) has been converted to agriculture. Human encroachment continues due to high population growth. With the herders come domestic dogs, which are numerous in the Ethiopian mountains. They act as reservoirs for infectious diseases, notably rabies and canine distemper. Moreover, given the very small global population of Ethiopian wolves, inbreeding and hybridisation form an additional threat. A handful of hybrid wolves were recorded in the Web Valley of the Bale Mountains in the 1980-90s, the result of crosses between female wolves and male domestic dogs. Political instability and conflict due to livestock predation can lead to killings of Ethiopian wolves, especially in the northern highlands. As more roads are built and traffic increases steadily, so does the risk of wolves being killed by vehicles.

Addressing the need

Both Dipsochelys/Aldabrachelys hololissa and D./A. arnoldi, thought to be extinct since the 1800s, were rediscovered in 1997 based on their morphologically distinctive appearance distinguishing them from the much more numerous Aldabra Tortoise from Aldabra Island, Seychelles. This captive breeding project (patronage: Sir David Attenborough) was supported from 2001 to 2011 (i.e. before the formal establishment of 1wild Foundation). In 2011 it was stopped by the Seychelles authorities.

The identification and rediscovery of Dipsochelys/Aldabrachelys hololissa and D./A. arnoldi as species formerly believed to be extinct is controversial and requires further genetic studies for confirmation. Various DNA studies produced inconclusive results, some positive, others negative.

Taking the positive results in combination with the description of the early museum specimens persuaded many tortoise experts that there was a strong case for separating these morphologically distinct Giant Tortoises from the much more numerous Aldabra tortoises, Aldabrachelys gigantea, which is native to Aldabra atoll, an outer Seychelles island 1000 km southwest of the granitic Seychelles.

This, as well as the breeding, was done on precautionary grounds (Gerlach J, 2011: Aldabrachelys hololissa [Günther 1877] – Seychelles Giant Tortoise. Conservation Biology of Freshwater Turtles and Tortoises. Chelonian research Monographs, No. 5). The breeding was unsuccessful at first, but by end 2010 had produced 180 offspring – all healthy strong tortoises, fed on the food that they would find growing in the wild upon reintroduction. However, the authorities of the Seychelles did not allow the planned release of the largest juveniles (20 - 30 kg) into the wild, despite the declaration of a national park on the target island, Silhouette.

Conservation action specifics

1/2