Ecological niche shift between diploid and tetraploid plants of Fragaria (Rosaceae) in China

Ecological niche shifts between diploid and tetraploid plants remains a topic with potential for plant ecology and evolution. Here, we identified populations of Fragaria (Rosaceae) from 169 sampling plots, classifying populations into two species groups (diploid and tetraploid) across China using flow cytometry. We then applied niche modeling to assess the ecological niche shift between diploid and tetraploid plants of Fragaria in China based on fieldwork and herbarium data. We explored the variables that best explained niche shifts between diploid and tetraploid plants. Compared to diploid plants, tetraploid plants are more likely to inhabit areas of higher altitude, lower temperature and lower precipitation, indicating that different ploidy levels are mainly associated with niche changes of altitude, temperature and precipitation. Diploid and tetraploid plants of Fragaria exhibit significant niche shifts (i.e. niche divergence between types). Ecological niche divergence between diploid and tetraploid plants is best explained by a shift in climate and altitude in biomes of conifer forests of southwestern China. Moreover, heterogeneity of soil further contributed to the observed niche shift between diploid and tetraploid plants. Our study provides novel insights into the role of niche shifts on genome mergers and duplications of Fragaria in China.