Moderate Population Structure in from the South American Atlantic Forest Biome.

is a widely distributed Neotropical species. In South America, it is abundant and adapted to different phytophysiognomies of the Atlantic Forest biome. Reproductive, chromosomal and enzymatic studies have indicated the existence of a differentiation among populations. In this work, the level of genetic diversity and the population genetic structure were analyzed using four population groupings. One hundred and twenty-six males collected from nine forest fragments were analyzed for 11 species-specific microsatellite loci. A total of 109 alleles, ranging from 2 to 16 alleles per locus, were detected. The highest mean observed heterozygosity - was estimated in samples from the largest collection areas, and the lowest was from a population where fire events are common. A low molecular variation, around 3% among populations and negative among groups, an absence of genetic and geographic correlations and a moderate genetic differentiation - = 0.0663 -indicated that is not strongly structured. Besides no overall genetic and geographic distance correlation, the pair of closest geographically populations Matão and Nova Granada showed the lower differentiation through , DC and a Neighbor Joining tree. Ribeirão da Ilha -RDI, an isolated insular population, was the most differentiated according to , DC and a cluster-based Bayesian analysis. The isolation of RDI that resulted in significant divergence could be ancient, because of sea level regressions/transgressions, or more recently via founder effect/genetic drift by anthropic action carrying hosts from continent to island. This work is important for understanding the genetic variability distribution of a Neotropical forest-dwelling species using for the first time, a wide population distribution approach.