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Status and distribution of the angonoka tortoise ( Geochelone yniphora ) of western Madagascar

Lora L. Smith·Don Reid·Bourou Robert·Mahatoly Joby·Sibo Clement
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Abstract

From 1993 to 1995, field surveys were conducted in western Madagascar to assess the current status of the angonoka tortoise ( Geochelone yniphora ) in the wild. Tortoise presence was documented at 10 of 11 localities surveyed. These localities represent at least five populations, all within a 30-km radius of Baly Bay, near the town of Soalala. The populations occur on fragments of habitat ranging from <50 to 4&ndash;6000 ha in size. One hundred and forty-five tortoises were marked in the five populations. Hatchling or juvenile tortoises were observed in all populations, indicating that reproduction was occurring. Most of the 145 tortoises (68%) were marked on Cape Sada, where monthly surveys were conducted. The tortoise density on the c. 150 ha peninsula was 0.66 tortoises/ha. The remains of 22 dead juveniles were found on Cape Sada over the 2-year period. This evidence, combined with the low number of juveniles in intermediate size classes in the Cape Sada population suggests that juvenile mortality may be high.

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Lora L. Smith, Don Reid, Bourou Robert, Mahatoly Joby, Sibo Clement. 1999. Status and distribution of the angonoka tortoise ( Geochelone yniphora ) of western Madagascar. https://doi.org/10.1016/s0006-3207(99)00044-0

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