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

Abstract

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.

The influence of Corvus frugilegus nesting on soil parameters and plant composition in poor and fertile habitats

“…Our results concerning soil pH decrease at the nesting sites correspond with other authors' results (e.g. Mun 1997;Ueno et al 2006;Okazaki et al 1993;Sigurdsson and Magnusson 2009). Although the habitats differed significantly in Mg and K content in the soil, Rook colony activity eliminated the differences in the content of these metals in both habitats.…”

“…Rook colony presence in both types of habitats leads to, among other things, an increase in organic matter volume, biogenic element content in the soil and soil acidity. Birds can act as a prominent soil-forming factor, influencing ecosystem development through guano deposition (Mun 1997;Ligęza and Smal 2003;Bancroft et al 2005;Liu et al 2006;Jakubas et al 2008;Sigurdsson and Magnusson 2009;Kitowski 2010, 2013), as well as contributing to soil eutrophication (Mun 1997;Bancroft et al 2005;Hobara et al 2005). On the one hand, the increase in soil fertility in both habitats under the nests can result from bird faeces deposition.…”

“…Especially, the effect of seabird colonies on their breeding biotopes has been comprehensively analysed (Godzik 1991;Fourgurean et al 1992;Odasz 1994;Otero Pérez 1998;Beyer et al 2000;Bancroft et al 2005;Liu et al 2006;Jakubas et al 2008;Mitoza 2009;Sigurdsson and Magnusson 2009;Khoreva and Mochalova 2009). What has far more seldom been the subject of analyses is the influence of land birds on soil transformations and the vegetation structure (Mun 1997;Hobara et al 2005).…”

Plant colonization, succession and ecosystem development on Surtsey with reference to neighbouring islands

“…From its birth, the island has lost half of its area due to heavy oceanic erosion (Jakobsson et al, 2007). In the colonization of the island, seagulls have come to play a key role in seed dispersal and nutrient transfer from sea to land, essential for ecosystem development Sigurdsson and Magnusson, 2010;del Moral and Magnússon, 2014;Leblans et al, 2014). These islands harbour some of the largest seabird colonies of the North Atlantic (Hilmarsson, 2009;Hansen et al, 2011), which greatly affect the vegetation and ecosystem structure.…”

Initial Effects of the August 2008 Volcanic Eruption on Breeding Birds and Marine Mammals at Kasatochi Island, Alaska

“…Much of the surviving biota, or biological legacy, is comprised of marine birds, which are effective vectors for transport of marine-derived nutrients (Stempniewicz, 1990;Maron et al, 2006) and plant material (Magnusson and Magnusson, 2000) to the terrestrial system. Therefore, seabirds can strongly affect the other land-based communities around their colonies (Petersen, 2009;Sigurdsson and Magnusson, 2009) and, thus, the recovery of breeding seabird colonies at Kasatochi could accelerate and shape the recovery of other island biota.…”