title: The impact of Great Cormorants on biogenic pollution of land ecosystems: Stable isotope signatures in small mammals.
abstract: Studying the isotopic composition of the hair of two rodent species trapped in the territories of Great Cormorant colonies, we aimed to show that Great Cormorants transfer biogens from aquatic ecosystems to terrestrial ecosystems, and that these substances reach small mammals through the trophic cascade, thus influencing the nutrient balance in the terrestrial ecosystem. Analysis of δ(13)C and δ(15)N was performed on two dominant species of small mammals, Apodemus flavicollis and Myodes glareolus, inhabiting the territories of the colonies. For both species, the values of δ(13)C and δ(15)N were higher in the animals trapped in the territories of the colonies than those in control territories. In the hair of A. flavicollis and M. glareolus, the highest values of δ(15)N (16.31±3.01‰ and 17.86±2.76‰, respectively) were determined in those animals trapped in the biggest Great Cormorant colony. δ(15)N values were age dependent, highest in adult A. flavicollis and M. glareolus and lowest in juvenile animals. For δ(13)C values, age-dependent differences were not registered. δ(15)N values in both small mammal species from the biggest Great Cormorant colony show direct dependence on the intensity of influence. Biogenic pollution is at its strongest in the territories of the colonies with nests, significantly diminishing in the ecotones of the colonies and further in the control zones, where the influence of birds is negligible. Thus, Great Cormorant colonies alter ecosystem functioning by enrichment with biogens, with stable isotope values in small mammals significantly higher in the affected territories.
authors.affiliation: Nature Research Centre, Akademijos 2, LT-08412 Vilnius, Lithuania. Electronic address: linasbal@ekoi.lt.
authors.forename: Linas
authors.initials: L
authors.lastname: Balčiauskas
authors.affiliation: Nature Research Centre, Akademijos 2, LT-08412 Vilnius, Lithuania; Center for Physical Sciences and Technology, Savanorių 231, LT-02300 Vilnius, Lithuania. Electronic address: raminta.skipityte@ftmc.lt.
authors.forename: Raminta
authors.initials: R
authors.lastname: Skipitytė
authors.affiliation: Nature Research Centre, Akademijos 2, LT-08412 Vilnius, Lithuania. Electronic address: mjasiulionis@ekoi.lt.
authors.forename: Marius
authors.initials: M
authors.lastname: Jasiulionis
authors.affiliation: Center for Ecology and Environmental Research, Vilnius University, Vilnius, Lithuania; Institute of Life Sciences and Technology, Daugavpils University, Parades Str. 1a, Daugavpils, LV-5401, Latvia. Electronic address: giedrius.trakimas@gf.vu.lt.
authors.forename: Giedrius
authors.initials: G
authors.lastname: Trakimas
authors.affiliation: Nature Research Centre, Akademijos 2, LT-08412 Vilnius, Lithuania. Electronic address: laiba@ekoi.lt.
authors.forename: Laima
authors.initials: L
authors.lastname: Balčiauskienė
authors.affiliation: Center for Physical Sciences and Technology, Savanorių 231, LT-02300 Vilnius, Lithuania. Electronic address: vidrem@fi.lt.
authors.forename: Vidmantas
authors.initials: V
authors.lastname: Remeikis
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D002247:Carbon Isotopes / Q000032:analysis*; D054750:Ecotoxicology; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D009587:Nitrogen Isotopes / Q000032:analysis*; D012377:Rodentia / Q000502:physiology*
chemical_list: D002247:Carbon Isotopes; D004785:Environmental Pollutants; D009587:Nitrogen Isotopes
keywords: Apodemus flavicollis; Interpopulation variation; Myodes glareolus; Nitrogen enrichment; Phalacrocorax carbo; δ(13)C and δ(15)N