Influence of environmental factors on the genetic variation of the aquatic macrophyte Ranunculus subrigidus on the Qinghai-Tibetan Plateau

Zhigang Wu,Juan Zhang,Hongwei Hou,Gerhard Wiegleb,Xinwei Xu

doi:10.1186/s12862-019-1559-0

Abstract

BackgroundDue to the environmental heterogeneity along elevation gradients, alpine ecosystems are ideal study objects for investigating how ecological variables shape the genetic patterns of natural species. The highest region in the world, the Qinghai-Tibetan Plateau, is a hotspot for the studies of evolutionary processes in plants. Many large rivers spring from the plateau, providing abundant habitats for aquatic and amphibious organisms. In the present study, we examined the genetic diversity of 13 Ranunculus subrigidus populations distributed throughout the plateau in order to elucidate the relative contribution of geographic distance and environmental dissimilarity to the spatial genetic pattern.ResultsA relatively low level of genetic diversity within populations was found. No spatial genetic structure was suggested by the analyses of molecular variance, Bayesian clustering analysis and Mantel tests. Partial Mantel tests and multiple matrix regression analysis showed a significant influence of the environment on the genetic divergence of the species. Both climatic and water quality variables contribute to the habitat heterogeneity of R. subrigidus populations.ConclusionsOur results suggest that historical processes involving long-distance dispersal and local adaptation may account for the genetic patterns of R. subrigidus and current environmental factors play an important role in the genetic differentiation and local adaptation of aquatic plants in alpine landscapes.

Highlights

Due to the environmental heterogeneity along elevation gradients, alpine ecosystems are ideal study objects for investigating how ecological variables shape the genetic patterns of natural species
An analysis of molecular variance (AMOVA) suggested only 4% of genetic variation was partitioned between subregions, and about half of the genetic variation was distributed among populations (Table 2)
Cluster A consists of GE1, GE2, GJ, ZB, NM and DT, when Cluster B consists of SG, DR, CM (SWQTP) and QM, DL (NEQTP) (Fig. 2)

Summary

Introduction

Due to the environmental heterogeneity along elevation gradients, alpine ecosystems are ideal study objects for investigating how ecological variables shape the genetic patterns of natural species. The highest region in the world, the Qinghai-Tibetan Plateau, is a hotspot for the studies of evolutionary processes in plants. We examined the genetic diversity of 13 Ranunculus subrigidus populations distributed throughout the plateau in order to elucidate the relative contribution of geographic distance and environmental dissimilarity to the spatial genetic pattern. By limiting gene flow within species, both spatial distance and environmental heterogeneity influence evolutionary as well as ecological processes [1, 2]. Gene flow among populations may be reduced due to the geographic isolation through the combined force of dispersal limitation and genetic drift [3]. Plant communities in mountains provide an important context for studying mechanisms of genetic structuring

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