The influence of environment and life‐history traits on the distribution of genes and individuals: a comparative study of 11 rainforest trees

Abstract

This study investigates patterns of genetic connectivity among 11 co-distributed tropical rainforest tree species from the genus Elaeocarpus across a biogeographic barrier, the Black Mountain Corridor (BMC) in the Australian Wet Tropics (AWT). We analysed a combination of allelic and flanking region sequence data from microsatellite markers, and evaluated the relative influence of environmental preferences and functional traits on genetic diversity and gene flow. The results indicate that only in three species geographic structuring of haplotype distribution reflects a north vs. south of the BMC pattern. Environmental factors linked with altitude were recognized as affecting genetic trends, but the selective processes operating on upland species appear to be associated with competitiveness and regeneration opportunities on poor soil types rather than climate variables alone. In contrast to previous observations within southeastern Australian rainforests, genetic differentiation in the AWT appears to be associated with small-fruited rather than large-fruited species, highlighting how external factors can influence the dispersal dimension. Overall, this study emphasizes the importance of considering functional and environmental factors when attempting generalizations on landscape-level patterns of genetic variation. Understanding how plant functional groups respond to environmental and climatic heterogeneity can help us predict responses to future change.

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics

“…However, it is worth noting that degrees of genetic isolation between rainforest trees across fragments of the Australian Wet Tropics have been linked to fruit size and dispersal mode in otherwise ecologically similar species [91,92]. This is an important observation and highlights that climate-based ecological modeling alone cannot fully explain species’ current distributions, nor adequately predict past ranges or barriers to gene-flow [93].…”

Landscape Patterns in Rainforest Phylogenetic Signal: Isolated Islands of Refugia or Structured Continental Distributions?

“…The influence of environmental and ecological factors, and functional traits (including those related to dispersal), on the assemblage of Australian rainforest plant species at plot, local area, regional, and continental scales has been tested using genetic, phylogenetic, and plot-based ecological and functional trait methods [21]–[25]. In addition, how those factors impacted on evolutionary history and local assemblage processes [21], and how the processes differed across regions at continental scales [26], [27] has been investigated for some species and clades. In several cases, research results have suggested more of a continuum of genetic diversity and distributions across broad geographic extents [23], [28].…”

Impact of climatic factors on genetic diversity of Stipa breviflora populations in Inner Mongolia

“…Genetic differentiation drives genetic diversity (Schaal et al, 1991) and the relationship between genetic differentiation and environmental factors has been a focus of recent studies (Rossetto et al, 2009;Finger et al, 2010;Santos et al, 2010;Martins et al, 2011). Random amplified polymorphic DNA (RAPD) markers can cover the total genome of organisms, including coding and noncoding regions, and reflect differences in the whole genome (Garcia et al, 1998).…”