title: Differential Responses of Arctic Vegetation to Nutrient Enrichment by Plankton- and Fish-Eating Colonial Seabirds in Spitsbergen.
abstract: The role of seabirds as sea-land biovectors of nutrients is well documented. However, no studies have examined whether and how colonial seabirds that differ in diet may influence terrestrial vegetation. Therefore, the purpose of the study was to describe and compare plant communities located in the vicinity of the two most common types of seabird colonies in Arctic, occupied by piscivorous or planktivorous species. Within 46 plots arranged in four transects in the vicinity of planktivorous (little auk,Alle alle) and piscivorous colonies (mixed colony of Brunnich's guillemot,Uria lomvia, and black-legged kittiwake,Rissa tridactyla) we measured the following: guano deposition, physical and chemical characteristics of soil, total nitrogen and its stable isotope signatures in soil and plants, ground vegetation cover of vascular plants and mosses, and the occurrence of lichens, algae and cyanobacteria. Using LINKTREE analysis, we distinguished five plant communities, which reflected declining influence along a birds fertilization gradient measured as guano deposition. SIMPROOF test revealed that these communities differed significantly in species composition, with the differences related to total soil nitrogen content and δ15N, distinctive levels of phosphates, potassium and nitrates, and physical soil properties, i.e., pH, conductivity and moisture. The communities were also clearly distinguished by distance from the bird colony. The two colony types promoted development of specific plant communities: the immediate vicinity of the planktivorous colony characterized by aDeschampsia alpina-Cerastium arcticumcommunity while under the piscivorous colony aCochlearia groenlandica-Poa alpinacommunity was present. Despite the similar size of the colonies and similar magnitude of guano input, differences between ornithogenic communities were connected mostly to phosphate content in the soil. Our results show that the guano input from seabirds which have different diets can affect High Arctic vegetation in specific and more complex ways than previously realized.
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk Gdańsk, Poland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Zwolicki
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk Gdańsk, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Zmudczyńska-Skarbek
authors.affiliation: Institute of Biology, The Faculty of Biology and Animal Science, Wrocław University of Environmental and Life SciencesWrocław, Poland; Department of Botany and Plant Ecology, The Faculty of Life Sciences and Technology, Wrocław University of Environmental and Life SciencesWrocław, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Matuła
authors.affiliation: Department of Ecology, Biogeochemistry and Environmental Protection, Faculty of Biological Sciences, University of Wrocław Wrocław, Poland.
authors.forename: Bronisław
authors.initials: B
authors.lastname: Wojtuń
authors.affiliation: Department of Vertebrate Ecology and Zoology, University of Gdańsk Gdańsk, Poland.
authors.forename: Lech
authors.initials: L
authors.lastname: Stempniewicz
keywords: bird cliff vegetation; guano deposition; guillemot; kittiwake; little auk; plant communities; soil chemistry