Palynology of two 4500 year old skua-mounds of the Arctic Skua (Stercorarius parasiticus (L.)) in Svalbard

• Published in: Polar Research
• Main Author: Van Der Knaap, W. O.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 1988
• Subjects: Arctic; Svalbard; Edgeøya; Arctic skua; Polar Research; Stercorarius parasiticus; Tundra; Spitsbergen
• Online Access: https://polarresearch.net/index.php/polar/article/view/2417; https://doi.org/10.3402/polar.v6i1.6845

Skuamounds are peaty hillocks up to 70 cm high used by Arctic Skuas (Stercorarius parasiticus (L.)) for surveying their breeding territory. Well-developed skua-mounds in Svalbard can be considered as small guanogenic bogs', because the peat formation depends on manuring by birds and the water-table in the mound is higher than the surrounding tundra. Peat sections measuring 34 cm and 40 cm from two skuamounds from Edgeøya and Spitsbergen were radiocarbon dated and studied for pollen and spores. Peat formation on the two skua-mounds started c. 4500 calendar years ago. Concentration values of longdistance transported pollen were used to detect time gaps in the records. The time gap in the skua-mound from Spitsbergen was found to be considerably greater than in the skuamound from Edgeøya. Erosion has progressed considerably further on the Edgeøya skua-mound than on the skua-mound from Spitsbergen due to differences in hydrology: the peat of the former mound is dry and unfrozen in summer, whereas in the latter mound it is wet and frozen. Time gaps and erosion are probably associated with phases of decreased manuring by birds. At two levels in the Edgeøya skua-mound there is evidence of a climatic change towards cooler conditions, one being an early major climatic shift and the other a later minor climatic shift. A similar major climatic shift is associated with one level in the skuamound from Spitsbergen.