Genetic diversity, population genetic structure and gene flow in the North African endemic and vulnerable Quercus afares Pomel. Revealed by microsatellites

Due to substantial population decline and habitat fragmentation, the North African Afares oak (Quercus afares Pomel.) is currently vulnerable and highly threatened. Like many endangered species, Afares is susceptible to biological and anthropogenic threats that can lead to genetic diversity loss and, ultimately, a heightened risk of extinction. Therefore, assessing genetic diversity is imperative for informing conservation strategies. In this study, genetic diversity and structure of the extant Algerian populations of Q. afares were analyzed. Genetic diversity, population structure, as well as gene flow and potential bottleneck effects were estimated using 16 polymorphic nuclear microsatellite markers. We found an unexpectedly high level of genetic diversity (H_o = 0.64, H_e = 0.60, A_r = 7.16) across the studied localities for a threatened species with restricted distribution range. Moreover, there were high levels of gene flow based on pairwise genetic differentiation estimates and minimal genetic structuring, among the fragmented, outbreeding localities (F_is = −0.11, p ˃ 0.05) of Q. afares. Additionally, no correlation was found between genetic and geographical distances (R_xy = −0.29, p = 0.5). These findings suggest that Q. afares stands represent a metapopulation. Despite the high genetic diversity of Q. afares, local populations in each small habitat patch remain at risk of extinction due to habitat loss and increasing anthropogenic threats. To minimize further loss of genetic diversity and habitat degradation, effective protection measures should be applied to Q. afares forests in Algeria. Conservation efforts should focus on habitat management and raising awareness among residents neighboring Afares oak forests.