Tragopogon in North America presents an ideal system for investigating intercontinental migration and the effects of recent polyploidy in a natural context. Marchant et al. (unpubl.) investigated the ecological shift of the diploid progenitors from their native European ranges to North America, comparing their actual and projected North American distributions based on ecological niche models (ENMs). They also compared the niches of the recently formed allopolyploids with that of their diploid progenitors. Marchant et al. (unpubl.) used digitized specimen records with ENM and multivariate analyses to compare the abiotic niches of three diploid Tragopogon species in their native European ranges, introduced North American ranges, and projected North American ranges based on the European ENMs. They compared those results to those of their recently formed North American allopolyploid derivatives to categorize niche shifts of the polyploids relative to their progenitors.
Significantly, the niches of the diploid progenitors differed substantially between their native and introduced ranges in terms of abiotic preferences and breadths. These differences could result from ecological changes in these species or methodological limitations of ENM projections. Both allopolyploids demonstrated niche intermediacy relative to the North American populations of their diploid progenitors. While the differences in niches between the native and introduced populations of the diploids are surprising, they demonstrate either ecological shifts in a recently introduced species or the methodological limitations of ENMs in predicting where immigrant species might establish and succeed.