Effects of fragmentation of evergreen broad-leaved forests on genetic diversity of Ardisia crenata var. bicolor (Myrsinaceae)

Due to the long generation times and high densities, dominant tree species usually did not respond consistently with theoretical predictions to the recent fragmentation. Genetic structures of shrubs and herbs, especially those with low densities, may be more sensitive to forest fragmentation. We studied the genetic structure of a self-compatible subshrub, Ardisia crenata var. bicolor (Myrsinaceae) in a recently fragmented landscape. Ten RAPD primers used for analysis generated a total of 76 bands. We found that A. c. var. bicolor had relatively low species-level (P ₉₅ = 63.2%; H = 0.106; Shannon diversity index (SI) = 0.246) and within-population diversity (P ₉₅ = 5.3-46.1%; H = 0.026-0.175; SI = 0.032-0.253), and significant population differentiation (G _ST = 0.445). Significantly positive relationships were found between measures of diversity (P ₉₅, H and SI) and the log of estimated population size. No significant relationship was observed between Nei's genetic distance and spatial distance of pairwise populations, indicating no isolation-by-distance. Given most species of forests are shrubs and herbs with short generation times, our observation indicated that distinct genetic consequences of recent fragmentation may be expected for quite a number of plant species.