REPLICATING RESULTS: RECENT MORPHOLOGY OF THE ANSE-AUX-CANARDS TIDAL MARSH IN A CLIMATE CHANGE SCENARIO

A recent discussion in psychology entitled “Interesting Results: Can they be Replicated?,” Winerman (2013) argues that, “replication is the gold standard. In theory, new knowledge doesn't make it into the canon until the studies that produced it have been verified, independently, by more than one researcher. But in practice … the field rarely lives up to that ideal...” This assertion is equally valid in geomorphology where numerous constraints prohibit the replication of results. In this study we return to Anse-aux-Canards, the site of one of the earliest quantitative studies of tidal marsh morphology in the St. Lawrence estuary by Allard in 1981. The purpose of revisiting Anse-aux-Canards tidal marsh is to assess two distinct tendencies of erosion of the low schorre and accretion of the high schorre noted by Allard (148). In the decades following the publication of that text, numerous authors have cited the study results, especially the erosion data for the low schorre that was estimated to be approximately 60 meters between 1963 and 1978. Using methods similar to those initially employed by Allard including analysis of aerial photographs, granulometry, sedimentation rates, tidal datum and biogeographical transects (aided by GPS), we assess the initial study results to determine the morphological tendencies of Anse-aux-Canards since 1981. The results of our study both confirm and infirm Allard’s observations. Like the initial study, we note seasonal and annual processes of vertical and lateral accretion and erosion of the entire marsh surface. However, where the first study recorded an ongoing process of linear erosion of the low schorre that was predicted to continue indefinitely, our replication of the original study illustrates that the low schorre is subject to seasonal and annual cycles of both accretion and sedimentation leaving it in dynamic equilibrium over the last half century (1963-2014). These results are contrary to the prevailing scientific interpretation that anthropogenic impacts (sediment trapping, climate change and sea level rise) are leading to significant erosion of marshes like Anse-aux-Canards. As such, our study raises numerous empirical, methodological and epistemological questions about current tidal marsh morphology in the St. Lawrence estuary and the need to replicate study results.