Comparative analysis of genetic diversity in wild and restored subtropical rainforest trees: Argyrodendron trifoliolatum, Ficus watkinsiana and Diploglottis australis

Abstract Since European settlement of Australia, substantial areas of subtropical rainforest have been cleared. More recently, effort is being made to restore small areas of this biodiverse ecological community. The financial investment and increasing reliance on ecological restoration in biodiversity conservation justifies a need for a better understanding of how to improve success at the genetic level. This research measures the levels of genetic diversity (allelic richness (Rs), expected heterozygosity (He), and inbreeding using Wright’s coefficient (F IS )) for expected neutral DNA markers in three characteristic Australian subtropical rainforest trees – white booyong ( Argyrodendron trifoliolatum ), Watkin’s fig ( Ficus watkinsiana ) and native tamarind ( Diploglottis australis ). Wild and restored populations of these species were sampled and compared in two neighbouring regions in Northeast New South Wales (the Tweed Caldera and the Big Scrub). There were no statistically significant differences in allelic richness or expected heterozygosity between wild and restored populations for any of the target species. Inbreeding was significantly higher in one of the restored versus wild population comparisons: F. watkinsiana in the Tweed (restored F = 0.20; wild F = -0.02; p = 0.01)). Small but statistically significant genetic differentiation between restored and wild populations (F ST < 0.17 Big Scrub, F ST < 0.053 Tweed) was detected for some of the comparisons between these cohorts. The comparable levels of genetic diversity observed in restored and wild populations targeted in this study are likely due to informed practitioner perspectives and practices, multiple introductions and high genetic diversity and low genetic differentiation within source populations.