Genetic diversity and structure of Drimys brasiliensis in southern Brazil: insights for conservation

Abstract

Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation. To date, however, little is known about the levels and distribution of genetic diversity of Drymis brasiliensis (Miers LC), a tree species from the Atlantic Rainforest. Therefore, in this study, we investigated how genetic diversity is distributed within and among populations of D. brasiliensis from southern Brazil using allozyme markers to genotype reproductive trees (8 populations) and seedlings (3 populations). Furthermore, in two populations, we established two permanent plots (5.1 and 1 ha) to analyze fine-scale genetic structure (FSGS). Studied populations presented low levels of genetic diversity (reproductive = 0.085; seedlings = 0.054) and high fixation indexes (reproductive = 0.396; seedlings = 0.231). Genetic divergence among populations was equal to 0.05, which is significant, signaling that few populations can conserve large portions of the species total genetic diversity. FSGS was only detected for one population, when reproductive individuals were separated by less than 40 m. Low genetic diversity combined with high fixation indexes clearly signal a risk of losing diversity. Therefore, conservation efforts should be aimed at enhancing gene flow within the studied populations.