A vegetation map and a digital elevation model over the Kapp Linné area, Svalbard : with analyses of the vertical and horizontal distribution of the vegetation

Abstract: A vegetation map and a Digital Elevation Model has been generated over a 54 km2 area situated at the western coast of Svalbard, at the Isfjorden fiord. The map is based on aerial photographs and a field survey made during the summer of 1994. The classification system used is described by Elven et alia (1990), for a similar study in Gipsdalen in the inner part of Isfjorden. The classification of the vegetation in our investigation area resulted in a map in scale l: 14 000, with a reliability of 61,3% and with 20 vegetation classes. The map was digitized and presented in scale l: 40 000. The two most widespread clas ses are type 113' -Exposed gravelly ridges with Salix polaris, and type 142 -Early snowbed/snowflush vegetation with Salix polaris. In areas with dolomitic bedrock, Dryas octopetala is frequent (type 112). Large areas are characterized by patterened ground and other frost sorting phenomena (type 112a', l13a', 226). The poorly drained sites have a thick moss layer and an abundance of grasses (type 222), while the areas below the birdcliffs are dominated by mosses and perennial herbs (subgroup 16). The DEM was generated using a method developed by Eklundh and Mårtensson (1994). The method is based on point sampling in a regular grid. The data was obtained from three maps, two of them made by Åkerman (1980) and the third one from a preliminary print from Norskt Polarinstitutt. Seven different interpolations were tested using the Inverse distance and Kriging methods, with a slight modification of the parameters. The best interpolation was achieved using Inverse distance with a search-window of 6 x 6 pixels and a distance weight of 2. The resulting DEMs had a resolution of 50m in the horizontal plane and 2m in the vertical plane. The DEM was combined with the vegetation map and some analyses of the vegetation were made, considering the preferred aspect, slope angle and elevation. The results showed that most of the plants grew at angles less than 5 degrees and at aspects between 225 -315 degrees (SW -NW) Hardly any vegetation was growing in the interval between 90 and 225 degrees (E -SW). Most of the vegetation preferred to grow beneath the 100 metres level. However, beneath the birdcliffs, vegetation could survive up to about 350 metres above sea level, 220 metres higher than elsewhere in the area.