Large-scale environmental niche variation between clonal and non-clonal plant species: Roles of clonal growth organs and ecoregions

Clonal plant species can produce genetically identical and potentially independent offspring, and dominate a variety of habitats. The divergent evolutionary mechanisms between clonal and non-clonal plants are interesting areas of ecological research. A number of studies have shown that the environmental niche theory can support the mechanisms of evolution across plant species clades at large scales. However, few studies have explored large-scale environmental niche variation between clonal and non-clonal plant species. Here, we used principal component analysis to quantify the environmental niche of 137 plant species belonging to 13 genera, including 87 clonal species and 50 non-clonal species. We then used a standardized effect size to assess environmental niche variation between clonal and non-clonal plant species within each genus, based on types of clonal growth organs and ecoregions. Our study provided the first evidence that there were significant environmental niche differences between clonal and non-clonal plant species at large scales. Such differences varied depending on the types of clonal growth organs and ecoregions. Clonal plants with different growth organs (i.e., epigeogenous stems, hypogeogenous stems, root-splitters, and adventitious buds on roots) contributed greatly to differences in climatic niches between clonal and non-clonal plants. Differences in environmental niches between clonal and non-clonal plant species also depended on ecoregion types. Specifically, the ecoregions of temperate broad-leaf and mixed forests can lead to environmental niche variation between clonal and non-clonal plant species. Our results provide new insights into the evolutionary divergence between clonal and non-clonal plant species. (C) 2018 Elsevier B.V. All rights reserved.