Demographic genetic structure of fragmented understory perennial plant populations

Recently, many plant populations are threatened with extinction due to habitat loss and fragmentation. One of the mechanisms elevating extinction risk is the loss of genetic diversity. Predicting future diversity loss is thus necessary to evaluate the viability of fragmented populations. Here, we used demographic genetic analysis, which is the comparative evaluation of genetic diversity among different age/stage classes, to examine temporal genetic dynamics in fragmented populations of an understory perennial herb, Trillium camschatcense (Melanthiaceae), in the Tokachi region, Japan. We sampled 16 individuals per life history stage (i.e. seedling, one-leaf, three-leaves-1, three-leaves-2, flowering) in two (large and small) populations. We performed MIG-seq and found that genetic diversity of newly germinated seedlings was significantly lower than that of matured flowering and three-leaf-2 in the small population. The results indicate that genetic diversity would decrease with generation turnover in the small population.