Two species of wild rice are found in Canada (Aiken et. al, 1989). Southern wild rice
(Zizania aquatica L.) is restricted to the lower Great Lakes where it is at the northern
limit of its range in North America. The southern species has been largely extirpated by
invasive carp and cattails. Northern wild rice (Zizania palustris L.) naturally occurs from
the eastern seaboard of Canada inland to eastern Manitoba but its range has been
extended westward through seeding efforts for commercial purposes. The open
panicles of southern wild rice make it prone to seed loss and has no commercial value.
This review describes the management efforts directed at both species. The particular
issue of invasive cattails now affects the northern species and efforts are described to
eliminate the potential catastrophic effect that occurred with the southern species.
The native species of cattails in Canada is Typha latifolia. Although the native species
can form large monocultures in areas formerly occupied by a variety of other species, it
is limited to depths of less than 25 cm. By comparison, the exotic, Typha angustifolia, or
the hybrid, Typha glauca, can tolerate depths of up to 1.5 m (Grace and Harrison,
1986). T. angustifolia is thought to have spread from the eastern seaboard of North
America inland to the Great Lakes in the late 19th century (Hotchkiss and Dozier, 1949).
It has spread further westward in the 20th century. The distribution maps of Grace and
Harrison (1986) show the species reached the Rainy River area by at least the time of
their publication. The exotic cattails occupy the same niche as wild rice with the
advantage of being a perennial and thus able to usurp the annual wild rice particularly
when water levels increase from year to year. This invasive species is now having
devastating effects on the largest stands of northern wild rice in the world (Lee, 2015).