Late 18th century drought-induced sand dune activity, Great Sand Hills, Saskatchewan

Abstract

Geomorphic evidence and optical ages from seven locations indicate that widespread dune activity occurred within the last 200 years in the Great Sand Hills region of southwestern Saskatchewan. Optical ages (n = 36) define an interval of dune activity bracketed by the earliest age of back ridges in the Seward sand hills (185 ± 8 years) and the average age of stabilized dune heads (about 105 years). During this interval, parabolic dunes were active in all areas studied. These ages indicate that the most recent interval of activity was initiated about AD 1800, and continued at a level higher than present for approximately 80 years. The most likely cause of dune activation was lower-than-average precipitation (relative to 1960–1991 values) through the 1700s, culminating in drought in the late 1700s, as evidenced in dendroclimatic records from the Cypress Hills and from the Rocky Mountain foothills. Dunes affected by such climatically induced regional activity require many decades to restabilize. Historical observations show that dunes in this area have been restabilizing throughout the 20th century. For the southern Canadian Prairies, a region with serious concerns about the implications of global warming, this study highlights the sensitivity of sand dunes to drought and cumulative moisture stress.

Sand dune stabilization reduces infiltration and soil moisture: a case study from the northern Great Plains

“…Not only could seasonal moisture usage increase but also the period of vegetation dormancy could decrease, reducing the length of time during which soil moisture recharge is most effective (Gosselin et al, 1999). Long periods of drought within the study area have been linked to periods of increased dune activity within Canadian Prairie sandhill ecosystems as recently as the mid-1980s (Wolfe et al, 2001). Should these deeper moisture reserves be sufficiently depleted, the vegetation present within Canada's prairie dune ecosystems would be more susceptible to drought, thereby increasing the probability of dune surface blowouts and dune reactivation during prolonged drought periods.…”

Late Quaternary Soil Development Enhances Aeolian Landform Stability, Moenkopi Plateau, Southern Colorado Plateau, USA

“…Global climate change models predict increasing aridity in many dryland settings and many researchers (e.g., [6]) speculate that decreasing effective moisture will reactivate dune fields under these model scenarios. Decreased effective moisture produced either through increased temperature and/or reduced precipitation is specifically predicted to destabilize vegetative cover on currently stable dunes and consequently cause reactivation of the many North American dune fields, such as those in the Great Plains (e.g., [7][8][9][10][11]) and even high-latitude dunes on vegetative cover on currently stable dunes and consequently cause reactivation of the many North American dune fields, such as those in the Great Plains e.g., [8][9][10][11][12] and even high-latitude dunes on the Canadian prairies [13,14]. But what will happen to aeolian sand dunes that are stabilized, not only by vegetation, but also by pedogenic alteration?…”

Remotely Sensing the Morphometrics and Dynamics of a Cold Region Dune Field Using Historical Aerial Photography and Airborne LiDAR Data

“…While these deposits are relicts of the vastly different climate of the Pleistocene and early Holocene [12,61], there are historical instances of dune reactivation following removal of sufficient amounts of overlying vegetation by physical or climactic events [54]. Climate alone can require centuries to reactivate dunes [62]. A combination of climate-induced drying and fire can more rapidly activate dunes.…”