Genetic resilience of Atlantic forest trees to impacts of biome loss and fragmentation

Understanding populational genetic diversity is crucial for making proper decisions about conservation and sustainable species management. In this work, we overviewed the conservation genetics of economically exploited tree species that are vulnerable to extinction in the Atlantic Forest of Brazil. For this, data on genetic parameters from research on 10 species of evergreen trees dwelling in that environment were compiled. Genetic variability differences between young and adults were assessed when data were available for both stages. Very low values observed for the probability of identity (PI) suggested that the SSR markers used had sufficient statistical power to consistently evaluate genetic variability of the populations. An innovative analytical approach using linear mixed-effect models revealed an integrated influence of the number of individuals sampled per population and the number of SSR markers on the output of the genetic estimators assessed. A large number of different alleles (NA) were observed in four out of the 10 species, indicating these populations may still hold unique and rare alleles. H O was smaller than H E for all but one of the studied species, suggesting higher numbers of homozygotes than expected. Comparison of data between ontogenic stages suggested that the time frame of habitat loss and fragmentation was not yet sufficient to cause significant loss of genetic diversity and differentiate populations. Our findings are discussed considering that intensity and duration of selective lodging and economic exploitation appear to be crucial for the underlying ecological patterns and for the definition of proper diversity conservation strategies.