This Thematic Issue on Controls and implications of source-to-sink environmental fluxes in selected cold climate environments produced by the I.A.G./A.I.G. SEDIBUD (Sediment Budgets in Cold Environments) working group (http://www.geomorph.org/sedibud-working-group/) presents a selection of papers that were presented and discussed during the 10th I.A.G./A.I.G. SEDIBUD Workshop on Monitoring of geomorphological processes in cold environments under climate change held 7–10 September 2016 in Bansko, Bulgaria.
Complex relationships exist between climate, vegetation cover and the dynamics of geomorphological Earth surface systems. Environmental changes have significant impacts on these relationships and on Earth surface system dynamics. The studies presented in this Thematic Issue collectively represent a cross section of latest research activities on drivers and implications of such relationships and environmental fluxes from different cold climate environments. Most of them concern the manifestation of hazardous processes and provide important results from their direct monitoring. The selected work covers cold environments in Norway, Romania and South Africa.
Pop et al. apply tree-ring analyses in order to document the spatio-temporal distribution of the past snow avalanche activity along two adjacent avalanche paths in the Piatra Craiului Mountains in the Southern Carpathians in Romania. Tree-growth anomalies found in cores and discs led to the determination of 8 avalanche events within path (1), respectively 10 avalanche events within path (2) spanning the 1950–2016 reconstructed period. Within the paths, the authors determined a minimum frequency of snow avalanches and defined the spatial extent for each reconstructed event. The analysis of weather conditions for two of the snow avalanche events documented in archival records and reconstructed by dendrogeomorphic analyses revealed the role of freezing/thawing periods, combined with heavy snowfalls, in triggering major snow avalanche events.
Laute & Beylich focus on the possible effects of climatic variations on the current and future snow avalanche activity in western Norway which is one of Norway`s most snow avalanche-prone areas. The authors statistically analyze long-term homogenized meteorological data from seven official meteorological stations and combine this with gained results and insights from a four-year high-resolution snow avalanche monitoring survey conducted within the study region. The potential effects and overall implications of changing snow avalanche activity are discussed. The detected and further expected increase of winter precipitation may lead to a generally higher snow avalanche frequency in the future. Due to the increased frequency of periods with air temperatures close or above the freezing point during the winter, also the probability of wet snow avalanches, slush flows and connected sediment transfers and hazardous impacts is expected to increase.
Beylich & Laute statistically analyze meteorological data from central Norway and present a ‘morphoclimatology’ that is especially oriented towards process geomorphological needs, focussing on aspects of the current wind, air temperature and precipitation regimes that control the type, frequency, intensity and duration of relevant geomorphic processes operating in the area. The authors discuss morphoclimatic controls of contemporary chemical and mechanical denudation in a boreal-oceanic drainage basin system. Due to the distinct characteristics of the present-day morphoclimate, runoff occurs year-round and chemical denudation clearly dominates over mechanical denudation. Mechanical denudation is strongly event-controlled and the highest share of annual fluvial transport occurs during spring snowmelt. It is expected that the postulated climatic changes will lead to increasing chemical and mechanical denudation rates in the study region.
Finally, Knight et al. use a mixed methodology to investigate relationships between periglacial landforms, slope aspect and their associated ecosystems, and the relative age relationships of these components at Mafadi Peak on the Lesotho – South Africa border. A distinctive alpine flora, belonging to the Drakensberg Alpine Centre of the wider Afromontane phytochorion, is found in association with different periglacial landforms. Slope and aspect have no significant effect on vegetation cover, plant species abundance and bare ground cover whereas the most likely microscale relationships are with surface geomorphic features. Weathering and soil development, influenced by climate, provide a substrate for a nutrient-deficient, sparse alpine flora and vegetation assemblage. The relationships between periglacial geomorphology and alpine ecosystems in southern African high mountain regions are found to be important with respect to ecosystem responses to ongoing climate change.
The Guest Editors of this Thematic Issue were responsible for the review process, and the preparation of this Thematic Issue would not have been possible without the help of the selected peer reviewers. The work and valuable contributions from the authors and all reviewers are greatly acknowledged. We also want to thank Peter Jansson and Hans Linderholm for their support for producing this Thematic Issue.
Selbustrand and Sofia, 16 April 2018