Impact of parent material, vegetation cover, and site wetness on variability of soil properties in proglacial areas of small glaciers along the northeastern coast of Sørkappland (SE Spitsbergen)

Abstract

Climate warming that began after the Little Ice Age (LIA) and glacier recession due to this warming are responsible for exposure of new areas, which previously had been covered with an ice mass in many parts of the world. Areas newly abandoned by glaciers are sites where primary plant succession and development of soil cover occur. The main aim of this study was to determine impact of parent material, vegetation cover, and site wetness on spatial variability of physical and chemical properties of surface soil layers in the oldest parts of proglacial areas of small and rapidly retreating glaciers such as Kambreen, Bevanbreen, and Coryellbreen, which are located along the northeastern coast of Sørkappland (SE Spitsbergen). Surface soil samples (up to a depth of 10 cm) were collected from sites, which differed in terms of the parent material of the soil (glaciofluvial deposits, glacial till), vegetation cover (bare soils, initial tundra vegetation, moss tundra vegetation), and site wetness (dry, moist, wet). Physical and chemical soil properties such as content of sand, silt, clay, TOC, TN, Si, Al, Ca, Mg, K, Na, P as well as soil pH and soil EC were determined. The obtained research results indicate that the studied surface soil layers are characterized by very high spatial variability of physical and chemical properties. The different parent material of soil (glacial till and glaciofluvial deposits) in the studied proglacial areas affects particle-size distribution, soil pH, soil EC, and content of TN, Ca, and Na. The surface layer of soils developed from glacial till has a finer texture, lower mean soil pH and EC, lower mean content of Ca and Na as well as higher mean content of TN relative to the surface layer of soils formed from glaciofluvial deposits. Vegetation cover, which is very sparse in the study area, has a very low impact on the variability of the properties of the studied surface soil layers. A comparison of bare soils with soils covered with initial and moss tundra vegetation communities indicates that only the more dense and best developed moss tundra vegetation community affects the higher mean content of TOC and TN in the soil. Site wetness is the most important among the studied three soil-forming factors affecting the spatial variability of the physical properties (particle-size distribution) and chemical properties (soil EC, content of TOC, TN, Si, Al, Mg, K, P) of the surface layer of the studied soils. Soils occurring at dry and moist sites are characterized by very similar physical and chemical properties, while soils occurring at wet sites exhibit significantly higher mean soil EC and higher mean content of the sand and Si as well as significantly lower mean content of TOC, TN, silt, clay, Al, Mg, K, and P.