Efficient in situ and ex situ conservation strategies are urgently neededin biodiversity hotspots, where high concentrations of endemic plant speciesare undergoing exceptional loss of habitat. In particular, determining seeddesiccation sensitivity is a key prerequisite to design storage methods useful forexsitu programs. In this study, we explored seed desiccation sensitivity and its linkwith phenological and morphological traits as well as with the environmentalvariables for 45 New Caledonian plant species. Desiccation sensitivity wasquantified through RH50, that is, the relative humidity at which 50% of initialviable seeds died. RH50 was found to be positively associated with the initial seedwater content, seed mass, precipitation seasonality, precipitation of the warmestquarter, and presence in rainforest habitats. In contrast, the ability of species toendure desiccation increased in drier habitats such as dry forest. We also foundthat desiccation sensitivity was consistent at the genus level. These new dataprovide the basis to establish conservation plans for a large array of plant speciesin New Caledonia. Moreover, this study may help us to better understand theunderlying mechanisms of desiccation sensitivity and to predict desiccationsensitivity of other taxa within the New Caledonian flora on the basis oftaxonomy, functional traits and environmental features.