Evolution and management of Atlantic Canadian coastal dunes over the next century

Abstract

ABSTRACT Dune systems in Atlantic Canada are relatively small given a relatively low sediment supply. The dunes are built primarily of reworked sediments as relative sea level (RSL) has risen. The foredune (at least) is reworked several times a decade by extreme weather events and many are transgressing on a decadal scale as a result of normal geomorphic processes. The key drivers shaping the dunes are, however, changing over time with climate change.The rate of RSL rise is accelerating, which will almost certainly mean an acceleration of dune transgression rates. As well, there is some evidence that storms are becoming more frequent and sea ice is diminishing, meaning more frequent reactivation. Predicting how dunes will respond to changes in the key controlling variables on an annual or decadal scale is challenging. Examination of how the dunes evolve on a decadal to century scale, however, suggests that the dunes in Atlantic Canada should continue to exist. Thus, we advocate using a dune management approach that focuses on minimizing human impacts and allowing natural processes to continue unimpeded. The highest priority for managing our coastal dunes should be to provide them with sufficient accommodation space into which they can transgress naturally.