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Biogeosciences Discuss., 6, 8393-8409, 2009
www.biogeosciences-discuss.net/6/8393/2009/
doi:10.5194/bgd-6-8393-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.


Ecosystem respiration, vegetation development and soil nitrogen in relation to breeding density of seagulls on a pristine volcanic island, Surtsey, Iceland

B. D. Sigurdsson1 and B. Magnusson2
1Agricultural University of Iceland, 112 Keldnaholt, 125 Reykjavik, Iceland
2Icelandic Institute of Natural History, P.O. Box 5320, 125 Reykjavik, Iceland

Abstract. Since its birth in 1963 by volcanic eruption in the North Atlantic Ocean off Iceland, Surtsey has been a unique natural laboratory on how organisms colonize volcanic islands and form ecosystems with contrasting structure and function. In July, 2004, ecosystem respiration rate, soil properties and surface cover of vascular plants were measured on 21 plots distributed among the main plant communities found 40 years after the primary succession started. The plots could be divided into two groups, inside and outside seagull (Larus sp.) colonies found on the island. Vegetation cover of the plots was strongly related to the density of seagull nests within and around them. The occurrence of seagull nests and increased vegetation also coincided with significant increase in ecosystem respiration, soil carbon and nitrogen, and with significantly lower soil pH and soil temperatures. The ecosystem respiration was high inside the gull colonies, similar to the highest fluxes measured in drained wetlands or agricultural fields in Iceland. The most important factor for vegetation succession and ecosystem function on Surtsey seems to be the amount of nitrogen, which was mainly brought in by the seagulls.

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Citation: Sigurdsson, B. D. and Magnusson, B.: Ecosystem respiration, vegetation development and soil nitrogen in relation to breeding density of seagulls on a pristine volcanic island, Surtsey, Iceland, Biogeosciences Discuss., 6, 8393-8409, doi:10.5194/bgd-6-8393-2009, 2009.   Bibtex   EndNote   Reference Manager    XML