Status and declining trend of Sparrow’s-egg Lady’s-slipper (Cypripedium passerinum) orchids in Pukaskwa National Park, Ontario, Canada

Abstract

Pukaskwa National Park hosts part of a disjunct population of the perennial orchid species Sparrow’s-egg Lady’s-slipper (Cypripedium passerinum) on the north shore of Lake Superior, Ontario, Canada. Monitoring of C. passerinum within Pukaskwa National Park occurred between 1979 and 2019. During that period, the total number of stalks and the number of C. passerinum colonies within the park have declined, while the proportion of flowering stalks at colonies has increased. Although the number of stalks at extant colonies is stable, this population may be suffering from lack of recruitment and is at risk of extirpation. We hypothesize that the decline and lack of recruitment are a result of changing habitat conditions due to natural and anthropogenic influence.