Monitoring threatened palm populations: a case study of three narrow endemic species of New Caledonia

Context New Caledonia is a hotspot of biodiversity, and among threatened species of the territory many are palms. Palms are sensitive to environmental changes and even more so when these species are narrow endemics. Monitoring populations is therefore an essential measure to conserve these emblems of tropical forest. Aims In this study, the population structure for three narrow endemic palms has been evaluated: Burretiokentia koghiensis, Cyphophoenix nucele and Chambeyronia houailouensis. Methods For each species, individuals were counted in several sampling plots. To understand the observed seedling deficit, we also assessed the impact of rat predation on fruit survival on C. nucele. Key results The three endangered species all have different structures. The structure of B. koghiensis shows that the population dynamics are currently undisturbed. The structure of C. nucele shows a very low number of seedlings, which does not affect the regeneration of the species. In contrast, the structure of C. houailouensis does not show a class deficit but neither does it fit the expected pattern. Conclusions All three species are subject to common threats such as introduced rats, yet their population structure is different. Implications The findings allow us to prioritise actions needed to restore regeneration of these species. These results underscore the importance of acquiring species-level data before implementing conservation actions.