Do leaf functional traits differ between 20–35-year-old transplanted and wild source populations? A case study involving five endangered tree species

Conservation of threatened species through translocation has become an effective way to combat species extinction worldwide. Plant functional traits are good predictors of plant performance and can reflect the adaptation strategies of plants to the environment. However, it is still unclear whether transplanted populations have comparable levels of leaf functional traits to their wild source populations. To assess the effectiveness of conservation-based translocation of long-living endangered tree species, we investigated the long-term (20–35 years) population dynamics of five co-existing endangered tree species (Davidia involucrata, Dipteronia sinensis, Pterostyrax psilophyllus, Tapiscia sinensis, and Tetracentron sinense) in transplanted populations, and compared the leaf functional traits between the transplanted and their wild source populations. We found that the survival rates of the five species in the transplanted populations ranged from 42.86% to 73.81%, and most of these species could blossom and yield fruit. All species had significant differences in some leaf functional traits between transplanted and wild populations. The intraspecific traits variation of some species in the transplanted populations was decreased compared with that in the wild populations on the whole. We conclude that after a long period of translocation, these species in transplanted populations were able to grow normally and most species become more efficient in resource acquisition or utilisation and more resources were available for growth. However, the intraspecific traits variation of some species in transplanted populations may lead to competitive exclusion, affect species coexistence, and thus affect their performance.