Population structure of lakeshore willows and ice‐push events in subarctic Québec, Canada

• Published in: Ecography
• Main Authors: Bégin, Yves, Payette, Serge
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1991
• Subjects: Ecology, Evolution, Behavior and Systematics; Canada; Subarctic
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1991.tb00627.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1991.tb00627.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1991.tb00627.x

The effects of ice‐push on shoreline population age structure of Salix planifolia was investigated at Clearwater Lake, a large lake (1270 km 2 ) located in the eastern Canadian subarctic. Twenty‐three willow stands located along a gradient of exposure to ice features were studied along the shoreline of a large island. Stand characteristics are significantly correlated with the degree of shore exposure. Drift‐ice action maintains continuously vegetation free substrata furthering willow colonization in shoreline habitat. Well‐rooted shrubs withstand disturbance through vegetative regenetation, that is profuse basal sprouting in response to ice‐scouring and breakage of stems. Age structure of basal shoots is highly correlated with ice‐scar dates. The rapid turnover of stem metapopulations frequently damaged by ice allows the shrubs to live older than usually. During recent decades, drift‐ice activity contributed to maintain a fast changing shore zone, favourable for the development of shrub populations. High frequency and magnitude of ice‐push events were caused by periodic high spring water levels.