Genetic diversity and contemporary population genetic structure of Avicennia marina from Mozambique

Abstract

The aim of this study was to determine the genetic diversity and population genetic structure of Avicennia marina, an important mangrove tree species with a wide distribution. Samples were collected from four sampling localities, characterised by different environmental conditions, situated along the coast of Mozambique within southern Africa: Pemba-Metuge, Bons Sinais Estuary, Costa do Sol and Inhaca Island. We used five species-specific polymorphic microsatellite loci for screening 20 samples from each of the sampling localities. The overall level of polymorphism observed was relatively high with 3–22 alleles detected at each locus. AMOVA showed the highest level of variation, 96.6 %, was located within populations. Pairwise FST comparisons were non-significant between sampling localities. No isolation by distance was detected. Structure results suggested the presence of one population after independent clustering of all samples. The results showed high levels of gene flow for A. marina along the coast of Mozambique and suggested the absence of barriers to gene flow. The results and information from this study will inform strategies for the conservation of A. marina. We discuss the importance of preserving the mangrove forest, supported by our own result, by managing and reducing anthropogenic activities that can damage the genetic diversity within these localities that are under high pressure due to urban growth. This will positively contribute to how and where effort and resources should be focused on for its conservation and sustainable management and utilisation.