Managing the risk of genetic swamping of a rare and restricted tree

Hybridisation is a complex process that has important evolutionary consequences. In the case of rare species, a comprehensive understanding of inter-specific hybridisation can be critical for their conservation and management. Eucalyptus tetrapleura is a rare species of ironbark that is restricted to a 40 km × 100 km area around Grafton on the North Coast of New South Wales (Australia), and is distinctive in that it has four ribs on the sides of its buds and fruits. In recent years, central populations of E. tetrapleura have been cleared to facilitate upgrades to one of the major highways in eastern Australia. This has led to increased habitat fragmentation, and there are now concerns that the species is at risk of genetic swamping by more common ironbark relatives. In this study, we investigated the population genetics and patterns of gene flow in E. tetrapleura. We used DArTseq to genotype samples collected from across the known distribution of E. tetrapleura, as well as leaf material...