Genetic variation and the conservation of isolated populations of Derris trifoliata (Leguminosae), a mangrove-associated vine, in southern China

Derris trifoliata is a mangrove-associated vine that plays an important role in maintaining coastal ecological balance. Due to human impacts, populations of this species have been isolated and fragmented in southern China. For their effective conservation, genetic variation of 15 D. trifoliata populations across the southern China coastlines was measured using ISSR markers. At the species level, genetic diversity was relatively high (P = 89.69%, He = 0.3065 and I = 0.4571). Based on Nei’s GST value and AMOVA, large genetic differentiation among populations was detected (GST = 0.4138; 43.67%, AMOVA). The results also showed significant differences either in genetic diversity (P < 0.05) or in genetic differentiation between the Hainan island and the mainland populations and between the inland and intertidal populations in the mainland. Our study suggests that ocean currents, fruit dispersal and habitat fragmentation may have played important roles in determining the genetic variation pattern in D. trifoliata. Our findings emphasize the need for appropriate conservation measures.

► Mangrove-associated species were highly disturbed by human activities.
► We examine the genetic variation of 15 Derris trifoliata populations in southern China coastlines.
► D. trifoliata has a high level of genetic variation and inter-population differentiation.
► The genetic variation patterns have significant differences between regions and between habitats.
► Fruit dispersal and habitat fragmentation play main roles in the shaping of variation pattern.