Bioclimatic evaluation of geographical range inFragaria(Rosaceae): consequences of variation in breeding system, ploidy and species age

The evaluation of the intrinsic and extrinsic forces that determine geographical range sizes and niche breadth is key to the understanding of species distributions and for informing the conservation of biodiversity. Fragaria (Rosaceae) contains the economically important cultivated strawberry (Fragaria × ananassa subsp. ananassa) and numerous wild species. Using georeferenced species records and global bioclimatic data, we describe the bioclimatic niches for 21 Fragaria spp. and investigate the relationship between their niches and geographical range size, breeding system, ploidy and time since divergence. We found no evidence of phylogenetic signal for bioclimatic niches. There was also no relationship between ploidy and geographical or bioclimatic range area, but geographical range area was significantly greater for species that were capable of self-fertilization. In addition, we found a significant decelerating relationship between species age and geographical range area. Overall, our results suggest that Fragaria spp., although similar in morphology and life history, show high levels of divergence in bioclimatic niches and significant over-dispersion along some bioclimatic gradients, suggesting evolutionary lability in physiology and climate tolerance. As a consequence, wild species will remain a valuable resource for cultivated strawberry sustainability, especially under changing future climate.