From mountaintops to metacollections: using genomics to evaluate ex situ conservation collections. A case study from tropical montane cloud forest plants

A core aim of ex situ conservation is to represent wild genetic diversity in managed living collections. For the climate-threatened tropical montane cloud forest (TMCF) flora of northeast Australia, an ex situ metacollection of plants and seeds has been established by the Tropical Mountain Plant Science (TroMPS) project. In this study we used reduced-representation sequencing (DArTseq) of wild, herbarium, and ex situ material alongside provenance information for ten species, to pursue two central aims: to characterise landscape-scale genetic structure across species' ranges, and to evaluate how well the assembled metacollections represent that wild diversity. Analyses revealed consistent patterns of genetic differentiation among mountain top populations across multiple species, reflecting the isolating influence of lowland gaps between upland habitats, with the degree of differentiation varying among species. These results provide the first genetic baseline for Australian TMCF flora and reinforce the importance of treating individual mountain top populations as distinct units for conservation management. Additionally, the project provided valuable insights into the logistical challenges of coordinated multi-institutional collecting, informing strategies for metacollection design more broadly. Evaluation of the metacollection revealed both strengths and gaps in representation across species, providing an evidence base to refine the current holdings and guide future targeted collecting to strengthen their long-term conservation value.