Which Environmental Factors Determine Recent Cryoturbation and Solifluction Activity in a Subarctic Landscape? A Comparison between Active and Inactive Features

Abstract

Environmental factors that affect the activity-inactivity variation of periglacial features may differ from those factors that control the distributional patterns of active features. To explore this potential difference, a statistically based modelling approach and comprehensive data on active and inactive cryoturbation and solifluction features from a subarctic area of Finnish Lapland are investigated at a landscape scale. In the cryoturbation modelling, vegetation abundance is the most important environmental variable explaining both the activity-inactivity variation and the distribution of active sites. The next most important variables are soil moisture and (micro)climatological conditions in the activity modelling, and slope angle and ground material in the distribution modelling. For solifluction, the key variables determining the activity-inactivity variation are mean annual air temperature and mean maximum snow depth, whereas vegetation abundance and slope angle control the distribution of active sites. Comparison between the environmental conditions of active and inactive periglacial features may provide new insights into activityenvironment relationships, which in turn are valuable when the effects of climate change on periglacial processes are explored.

Winter warming effects on tundra shrub performance are species‐specific and dependent on spring conditions

“…This highlights the need for accurate model predictions of how winter climate change will affect the interplay of snow and soil temperatures experienced by plants, such that empiricists can evaluate their consequences with higher certainty. Increased shrub height and cover may lead to a strong positive feedback effect on winter soil temperatures and plant growth via snow trapping (Sturm, Racine, & Tape, ; Williams & Smith, ), which will have substantial consequences for C dynamics in these globally important ecosystems, for example via its effects on respiration (Liptzin et al., ; Semenchuk, Christiansen, Grogan, Elberling, & Cooper, ), cryoturbation (Hjort, ; Kade & Walker, ) and C‐sequestration into plant biomass (Epstein et al., ). Additionally, changes in plant growth onset timing and biomass after altered winter and spring conditions may significantly affect plant–herbivore interactions in these systems (Olofsson et al., ; Pettorelli et al., ) and biotic cascades into the soil system (Wookey et al., ).…”

Solifluction rates and environmental controls at local and regional scales in central Austria

“…Jaesche et al 2003 ; Matsuoka 2011 ). Understanding and predicting the evolution of periglacial landforms related to solifluction requires quantitative relationships between the rate of solifluction and these variables (Matsuoka 2001 ; 2011 ; Hjort 2014 ).…”

Environmental Controls of InSAR‐Based Periglacial Ground Dynamics in a Sub‐Arctic Landscape

“…The presence of vegetation may also influence the snow distribution, leading to variable water content and thus promoting differential frost heave (Daanen et al., 2008; Nicolsky et al., 2008). In general, as discussed by Hjort (2014) and Hjort and Luoto (2009), the vegetation is mostly an indirect factor for periglacial activity and encompasses a variety of species with different habits, which can have contrasting impacts on ground stability. This complexity may explain the ambiguous relationship with the response variables.…”

“…The relatively low model performance (Table 3) in this study can be explained by a) the overall low magnitude of ground movement across the area; b) the complex and indirect relation between environmental variables and the ground velocities, as well as the scale discrepancy between measurements and processes; and c) the relatively small number of observations in the calibration sets (on average 1,100) that may not cover the entire gradient of environmental conditions in the study area. Contrary to the previous studies applying modeling based on field-mapped processes and landforms (Hjort, 2014;Hjort & Luoto, 2009;Hjort et al, 2007), the responses here represent ground velocity regardless of the underlying processes. The unexplained variation by the models is arguably attributed to the frost susceptibility of ground material, finescale soil moisture, and microclimatic conditions (e.g., solar radiation, wind processes) (Aalto, Scherrer, et al, 2018), which could not be accounted for at optimal thematic or spatial resolution.…”