Using ice‐scars as indicators of exposure to physical lakeshore disturbances, Corvette Lake, northern Québec, Canada

Abstract

The hypothesis tested in this study is that ice‐scars recorded by lakeshore tree stands can be used as an integrative proxy indicator of the overall hydrodynamic disturbance regimes affecting northern lakeshores. A 2‐km‐long shore segment was divided into 21 sections according to shore orientation and slope. An ice‐scar chronology and a wave exposure index value were obtained for each shore section. A significant relationship was found between ice‐scar chronology and wave exposure index, which indicates that the mechanical action and physical force of ice activity mainly depend on the same environmental factors determining exposure to wave action (i.e. fetch, wind direction and velocity, and shore slope). The spatial and temporal variability of ice‐scar chronology features also corresponded to the distribution of geomorphological features associated with ice activity along the shoreline. Analysis of the hydrological signal associated with these ice‐scar chronology features indicated that an increase in ice‐push frequency observed in the 1930s can be associated to an increase in wave action related to more frequent spring floods maintaining high lake levels during the ice‐free period. This study demonstrates that ice‐scars have strong potential as proxy indicators of shore exposure and provide a temporal frame to reconstruct the history of lakeshore disturbance regimes at a local scale. Together, ice‐scars and wave exposure index provide essential information to interpret the evolution of lakeshore vegetation mosaics in time and space. Copyright © 2012 John Wiley & Sons, Ltd.

The role of ice dynamics in shaping vegetation in flowing waters

“…Along small streams, ice rarely causes tree trunks to break and re-sprout but rather causes scarring of trees (Sigafoos, 1964). Analogous to using trees with fire scars to interpret fire regimes, trees with many ice scars can indicate ice disturbance regimes (Tardif & Bergeron, 1997;Lemay & Bégin, 2012). Ice scars on trees can also be found above normal flood levels, indicating exceptionally high flood levels during ice break-up (Bégin, 2000(Bégin, , 2001.…”

Driftcretions: The legacy impacts of driftwood on shoreline morphology

“…Spruce germination around 1950 probably correlates with unrecorded high flows in the late 1940s or with a period of multiple large seiches during . Development of an ice push event chronology using ice-scar chronologies on lakeshore trees and shrubs, as done for large northern lakes in Québec [Bégin, 2000;Lemay and Bégin, 2012], would greatly augment understanding of relationships among flow, ice push, and berm formation. [Brock et al, 2010], large seiche events [Gardner et al, 2006], and construction of the W.A.C.…”