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Naturally fragmented and isolated distribution in subtropical grassland patches affects genetic diversity and structure at different spatial scales: The case of Tibouchina hatschbachii , an endemic shrub from Brazil
Author(s) -
Maia Fabiano R.,
Sujii Patricia S.,
SilvaPereira Viviane,
Goldenberg Renato
Publication year - 2017
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.1700164
Subject(s) - biology , genetic diversity , genetic structure , biological dispersal , ecology , genetic variation , gene flow , habitat fragmentation , grassland , evolutionary biology , biodiversity , population , demography , genetics , sociology , gene
PREMISE OF THE STUDY: The genetic structure of organisms results from the interactions between life history traits and the ecological and demographic characteristics of the landscape that shape the intra‐ and interpopulation genetic variation in space and time. In this study, we used a species restricted to islands of grassland vegetation in southern Brazil to investigate the effects of its naturally fragmented distribution on diversity and genetic structure patterns. METHODS: Diversity and intra‐ and interpopulational genetic structure were analyzed using polymorphisms of eight nuclear microsatellite markers in 205 individuals of T. hatschbachii and Bayesian and multivariate methods. KEY RESULTS: At the intrapopulation level, populations presented low genetic diversity and strong spatial genetic structure, indicating a greater spatial autocorrelation until ∼50–500 m. At the interpopulation level, genetic variation partitioned into two geographically structured genetic clusters. Gene flow through pollen was more efficient than gene flow by seeds. CONCLUSIONS: Genetic structure was influenced locally by seed and pollen dispersal dynamics and regionally by fragmentation of the grassland landscape. This study highlights the importance of geological barriers, and potentially a role for genetic drift, in influencing diversification of species in subtropical grasslands of southern Brazil.