Ogden's Pondweed (Potamogeton ogdenii) COSEWIC assessment and status report: chapter 1

Assessment Summary – April 2007

Common name: Ogden’s Pondweed

Scientific name:Potamogeton ogdenii

Status: Endangered

Reason for designation: This species is an aquatic plant that is globally at risk with low population numbers and only 11 extant sites known worldwide. In Canada, it is known from only 3 sites in southeastern Ontario where it was last collected in 1987. Recent fieldwork has documented the loss of habitat and probable extirpation of one population but failed to relocate the others – one of these is a historic site in a relatively undisturbed region with no specific locality information. The presence of aquatic invasive plants in areas around presumed extant populations suggests a further decline in overall area and quality of habitat for native pondweeds. However, the species, which is easily confused in the field with other similar narrow-leaved pondweeds, may still be present in Canada in suitable habitats in the vicinity of previously known sites.

Occurrence : Ontario

Status history : Designated Endangered in April 2007. Assessment based on a new status report.