Ecological Characterization of Syzygium (Myrtaceae) in Papua New Guinea

Syzygium is the largest woody genus of flowering plants in the world and one of the most important components of the forest vegetation in Papua New Guinea (PNG). Although the systematics of the genus is improving, a comprehensive appraisal of the environmental features and gradients of its species is still lacking. Our work aims to fill this gap by analyzing the georeferenced specimens collected at the Lae National Herbarium of PNG. A data set of 1,563 records of 131 species was used to assess their altitudinal gradients and the correspondence with the main vegetation types and to model their spatial ecological niche with respect to climatic, topographical, and pedological variables. Several species were found to be widely distributed throughout the region, while other species were restricted to narrow altitudinal belts or only occurred in specific vegetation types. Overall, the genus is also characterized by an increasing altitudinal turnover likely due to topography-driven isolation. The improved knowledge of the ecological requirements of Syzygium assists in the elaboration of effective conservation strategies and improves in situ species identification of this taxonomically difficult group.