Spatial Genetic Patterns and Distribution Dynamics of the Rare Oak Quercus chungii: Implications for Biodiversity Conservation in Southeast China

Jiang Jiang,Deng Deng,Xu Xu

doi:10.3390/f10090821

Abstract

A rapidly changing climate and frequent human activity influences the distribution and community structure of forests. Increasing our knowledge about the genetic diversity and distribution patterns of trees is helpful for forest conservation and management. In this study, nSSRs (nuclear simple sequence repeats) were integrated with a species distribution model (SDM) to investigate the spatial genetic patterns and distribution dynamics of Quercus chungii F.P.Metcalf, a rare oak in the subtropics of southeast China. A total of 188 individuals from 11 populations distributed across the natural range of Q. chungii were genotyped using nine nSSRs. The STRUCTURE analysis indicated that genetic admixture was present in all populations, but the population genetic variation and genetic differentiation were related to their geographical distributions. The SDM result indicated that Q. chungii retreated to the Nanling Mountains and adjacent areas during the Last Glacial Maximum (LGM) period, which corresponds to higher genetic diversity for populations in this region. Landscape genetic analysis showed that the Nanling Mountains served as a corridor for organism dispersal at the glacial and interglacial periods within the Quaternary. Based on these results, we propose that establishing nature reserves to protect the ecological corridor across the Nanling Mountains is necessary for the conservation of regional species genetic diversity, as well as the ecosystem of evergreen broadleaved forests in southern China. The study combines species distribution models and genetic diversity to provide new insight into biodiversity conservation and forest management under future climate change.

Highlights

Forests play crucial roles in both the regional ecology and economy, including maintaining species diversity, regulating climate, conserving water and soil, and providing timber and food [1,2].A great deal of research is still required to better understand and untangle the biotic and abiotic factors that drive speciation, genetic differentiation, and the distribution dynamics of trees [3,4,5,6].The demographic history and distribution dynamics of trees can be reconstructed based on a species genetic diversity, paleontology data, and a species distribution model, or the combination of these data [7,8]
We examined the spatial genetic patterns, potential distribution dynamics, and dispersal corridor of Q. chungii using nSSRs and a species distribution model
The high area under curve (AUC) scores (AUC = 0.999) in the model evaluation indicated that the species distribution model (SDM) analysis performed well

Summary

Introduction

A great deal of research is still required to better understand and untangle the biotic and abiotic factors that drive speciation, genetic differentiation, and the distribution dynamics of trees [3,4,5,6]. The demographic history and distribution dynamics of trees can be reconstructed based on a species genetic diversity, paleontology data, and a species distribution model, or the combination of these data [7,8]. Understanding the historical distribution and divergence dynamics of trees is informative for untangling the species evolutionary histories, and for predicting the responses of Forests 2019, 10, 821; doi:10.3390/f10090821 www.mdpi.com/journal/forests. Forests 2019, 10, 821 forests to rapid climate change in the future. Even more importantly, this understanding can help to make forest conservation more efficient and management strategies more effective. Recent studies indicate that Quercus is comprised of two subgenera, subg

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