| Summary: | Appendix 1 removed due to copyright restrictions: Trewick, S.; Brescia, F.; Jordan, C. (2009) Diversity and phylogeny of New Caledonian Placostylus land snails; evidence from mitochondrial DNA. In: GRANDCOLAS, P. (ed.), Zoologia Neocaledonica 7. Biodiversity studies in New Caledonia. Mémoires du Muséum national d’Histoire naturelle, 198: 421-436. This study focuses on two endemic New Caledonian land snails: Placostylus fibratus and Placostylus porphyrostomus (known locally as bulimes) which are in decline and listed as vulnerable by the IUCN. On the Isle of Pines, both species are highly-valued commercially and traditionally harvested species suffering from exploitation for human consumption. In the dry forests of the New Caledonian mainland, P. porphyrostomus, especially, is threatened due to habitat degradation and loss, and rodent predation. Prior to this study, the life histories, impact of human harvest, and population trends remained largely unknown for the New Caledonian Placostylus species and restoration trials for their conservation had not been undertaken. Addressing these deficiencies forms the foundation for the thesis, and the findings are used to formulate recommendations for management and conservation. On Isle of Pines, the extent and densities of P. fibratus are greater than the scattered and isolated populations of P. porphyrostomus found on the island and in the dry forests of the Mainland. Placostylus snails are long-lived (estimated at 19 to 39 years for P. fibratus in this study) and relatively slow growing, taking up to four years to reach sexual maturity (aperture lip ≥3.5 mm). Non-exploitative mortality factors impinge disproportionately on juveniles. Consequently, the age-structure of populations is changing, with juveniles becoming increasingly rare. Annual survival rates for P. fibratus are estimated as 59.0% for juveniles and 70.0% for adults. The major cause of mortality of juveniles was predation by introduced rodents (the ship rat Rattus rattus, the Polynesian rat Rattus ...
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