Long‐term sand dune spatio‐temporal dynamics and endemic plant habitat extent in the Athabasca sand dunes of northern Saskatchewan

Abstract

AbstractThe Athabasca sand dunes in northern Saskatchewan and north‐east Alberta are a unique landscape of moving sand that hosts nine narrowly distributed endemic vascular plant taxa. We modeled the extent of habitat for each species, corresponding dune morphologies in species habitat, spatial and temporal variation in dune environments, and rates of woody vegetation encroachment at dune boundaries to support an assessment of long‐term threats for the Athabasca endemic dune flora. Landsat images were used to maximize the time spans and areal coverage of the study. The Athabasca sand dunes are currently active and characterized morphologically by crescentic ridge and morphodynamically by transverse form dunes. Longitudinal sand movement parallel to the dune axis resulted in the creation of new dune areas along the east and south‐east boundaries of the dune fields at a rate of 0.14 km2 year−1. Forest succession along the western boundaries of the dune fields resulted at an annual dune loss of 1.98 km2 year−1. The net extent of dune stabilization between 1985 and 2014 was 53.76 km2 or nearly 20 percent of the total open sand dune extent. All habitat modeling methods showed robust performance (>0.5 AUC), with the best performance in most cases from generalized linear models. Estimated total available/occupied habitat was comparatively low for the least abundant species Achillea millefolium (38.92 km2) and Armeria maritima (48.82 km2), and of those areas 53.5% and 16.29%, respectively, are influenced by dune stabilization. Continuing stabilization of the Athabasca sand dunes region may present conservation concerns for these narrowly distributed endemic taxa.