Résumé
Forty-one endemic conifer species occur on New Caledonia's ultramafic substrates (known locally as ‘‘terrains miniers''), the source of nickel ore deposits being exploited at a rapidly increasing rate. Impacts of the removal of native vegetation and its destruction by the deposition of mine wastes are compounded by fire, which has dramatically reduced and fragmented the original cover. A new threat evaluation of these conifers, now being incorporated into the IUCN Red List, is presented. A conservation action plan is proposed to ensure their long term survival. Four species are classified as Critically Endangered (CR), 13 Endangered (EN), 6 Vulnerable (VU), 7 Nearly Threatened (NT) and 11 Least Concern. Wetland habitats contain two threatened species (i.e., CR, EN or VU), all inadequately protected in a single reserve. High altitude forest and maquis (a characteristic scrub-like vegetation) have four threatened and three NT conifers only partially encompassed in protected areas, some open to mining. Thirteen threatened species are restricted to low- and mid-elevation forests, and another three that can also occur on non-ultramafic substrates have isolated, unprotected populations in small forest remnants. Fire and land clearing for mining threaten two conifer species in low- to mid-elevation maquis along with subpopulations of five primarily forest species. Conserving the threatened conifers on terrains miniers will require coordinated measures including: comprehensive protection of forest remnants by forbidding mine waste stockpiling; establishment of new reserves, especially in key unprotected massifs; effective fire prevention; restoration of forest corridors between forest remnants; and multiplication/transplanting of selected species