Spatial genetic structure within populations and management implications of the South American species Acacia aroma (Fabaceae)

POMETTI, CAROLINA; BESSEGA, CECILIA; CIALDELLA, ANA; EWENS, MAURICIO; SAIDMAN, BEATRIZ; VILARDI, JUAN

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2018 vol. 13 p. 1 - 14

1932-6203

The identification of factors that structure intraspecific diversity is of particular interest forbiological conservation and restoration ecology. All rangelands in Argentina are currentlyexperiencing some form of deterioration or desertification. Acacia aroma is a multipurposespecies widely distributed throughout this country. In this study, we used the AFLP techniqueto study genetic diversity, population genetic structure, and fine-scale spatial geneticstructure in 170 individuals belonging to 6 natural Argentinean populations. With 401 loci,the mean heterozygosity (HE = 0.2) and the mean percentage of polymorphic loci (PPL =62.1%) coefficients indicated that the genetic variation is relatively high in A. aroma. Theanalysis with STRUCTURE showed that the number of clusters (K) was 3. With Genelandanalysis, the number of clusters was K = 4, sharing the same grouping as STRUCTUREbut dividing one population into two groups. When studying SGS, significant structure wasdetected in 3 of 6 populations. The neighbourhood size in these populations ranged from15.2 to 64.3 individuals. The estimated gene dispersal distance depended on the effectivepopulation density and disturbance level and ranged from 45 to 864 m. The combinedresults suggest that a sampling strategy, which aims to maintain a considerable part of thevariability contained in natural populations sampled here, would include at least 3 unitsdefined by the clusters analyses that exhibit particular genetic properties. Moreover, thecurrent SGS analysis suggests that within the wider management units/provinces, seed collectionfrom A. aroma should target trees separated by a minimum distance of 50 m but preferably150 m to reduce genetic relatedness among seeds from different trees.