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

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.

KEYWORDS:

• Atlantic Canada
• coastal dunes
• evolution
• management

Acknowledgments

The figures were prepared with the help of Marie Puddister, University of Guelph. Figure 4A and B also appear in Davidson-Arnott et al. (2019). Sean Blaney and Sarah Robinson, Atlantic Canada Conservation Data Centre, provided information on invasive species. The number of colleagues and funding bodies that contributed to the research leading to this paper are simply too numerous to mention – but we gratefully thank them all.

Disclosure Statement

We have received no financial or other benefits from the direct applications of this research.

Tribute to Dr. Tony Orme

Dr. Orme was an ‘old-school’ physical geographer. He was broadly trained, in the British tradition of the day, and his life’s work reflects this. As others have written, his research focused on a variety of geographical/geomorphic systems “from the mountains to the sea”. He understood the intersections between human and natural systems (e.g., Orme et al., 2011; “Beach changes along the southern California coast during the twentieth century: A comparison of natural and human forcing factors”). He was also keenly interested in the history of our discipline (e.g., Orme, 2013; “The Four Traditions of Coastal Geomorphology”). His work could be used in many cases to address coastal management issues. In short, he was a well-rounded geographer who thought and researched broadly, an increasingly rare trait in a world of ever-increasing specialization and narrow focus. We will miss him.

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).