Cervus canadensis nelsoni and Cervus canadensis manitobensis are not considered separate taxa from the nominate Cervus canadensis canadensis, which was previously recognized as the "Eastern Elk", the extirpated wapiti population east of the Mississippi. The IUCN typically notes recently extirpated taxa, but instead claims C. c. canandensis represents the majority of the North American population. (http://www.iucnredlist.org/details/55997823/0) This reflects increasing consensus among geneticists that subspecific taxa for the wapiti are inflated (Ludt et al., 2004). (http://www.sciencedirect.com/science/article/pii/S1055790303003841?via%3Dihub) Some authorities would go so far as to say there is only one subspecies in North America (meaning it would include the Tule and Roosevelt Elks), but until greater consensus emerges regarding that information, it is safer to conform to iNat's databases.