Schinus terebinthifolius: Population structure and implications for its conservation

• There is no significant correlation between genetic and geographic distances.
• It was found an excess of heterozygosity which suggests a bottleneck in the area.
• Nine genetic clusters were identified.
• The effective population size found high degree of relatedness between individuals.
• The three studied populations were delimited as Management Units.

The high demand for the fruit of Schinus terebinthifolius, known as the Brazilian Pepper Tree, has generated attention for vegetation studies in the São Francisco River Basin, Sergipe State, Brazil. The fruit is heavily exploited and the genetic consequences of the exploitation are currently unknown. The objective of this study was to estimate the genetic diversity of three distinct populations of S. terebinthifolius from Caatinga, Atlantic Forest, and Ecotone, and to define priority areas between them for conservation in the river basin. The studied area is located along 81.52 km of the São Francisco River Basin. The sample of 162 individuals was studied by ISSR molecular markers. There are recent genetic bottlenecks in studied populations, and the genetic differentiation among populations was Fst = 0.27. The populations from the Caatinga and Atlantic Forest biomes presented a low level of genetic divergence (0.14). There was no correlation between the genetic and spatial distance between the populations. We detected genetic barriers and nine distinct genetic groups (K = 9). The presence of exclusive loci in each studied population provides evidence to support the definition of these populations as potential management units for conservation.