Southern Ocean seabird population shifts over the Holocene revealed by peat sequestration of mercury from guano
Abstract
Monitored seabird populations have declined by up to 70% worldwide since the 1950s. Yet, data on long-term seabird population dynamics prior to the anthropogenic era are largely unknown. This limits our ability to understand future population trajectories, particularly in the Southern Ocean, where seabirds are facing multiple environmental threats. Here, we use mercury (Hg) derived from seabird guano in peatland catchments as a tracer of colony population sizes on sub-Antarctic Bird Island (South Georgia). Peat Hg flux and isotope signature results show that the first sustained seabird colonies after deglaciation were established on the island between 6800 and 6100 years ago, predating evidence for colonization on other sub-Antarctic islands by more than 1,000 y. The four subsequent periods with large local seabird populations occurred during phases of less intense Southern Hemisphere westerly winds. Our study unveils significant and repeated millennial-scale shifts in seabird abundance in response to natural climate changes, implying that the present-day increase in westerly wind intensity may lead to further declines in seabird populations in the Southern Ocean.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (33)
Chuxian Li
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Stephen J. Roberts
British Antarctic Survey, Natural Environment Research Council
Martin Grosjean
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Adrien Mestrot
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Martin Wille
Institute of Geological Sciences, University of Bern
Richard A. Phillips
British Antarctic Survey, Natural Environment Research Council
Maxime Enrico
Université de Pau et des Pays de l’Adour, LFCR, E2S UPPA, CNRS
Kevin Bishop
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Ulf Skyllberg
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Dmitri Mauquoy
School of Geosciences, University of Aberdeen
Clemens von Scheffer
School of Geosciences, University of Aberdeen
Thomas Theurer
School of Geosciences, University of Aberdeen
David Muirhead
School of Geosciences, University of Aberdeen
Alex Whittle
British Antarctic Survey, Natural Environment Research Council
Angela Gallego-Sala
Geography Department, University of Exeter
Jeroen E. Sonke
Géosciences Environnement Toulouse, Université de Toulouse, CNRS, IRD, Toulouse
François De Vleeschouwer
Instituto Franco-Argentino para el Estudio del Clima y sus Impactos (IRL3351 IFAECI/CNRS-CONICET-IRD-UBA), Universidad de Buenos Aires
Nathalie Van der Putten
Department of Earth Sciences, Vrije Universiteit Amsterdam
Pascale Braconnot
Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay
Olivier Marti
Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay
Stefan Osterwalder
Department of Geography, Hydrology and Climate, University of Zurich
Nina Buchmann
Grassland Sciences, Institute of Agricultural Sciences, ETH Zurich
Thomas Frölicher
Climate and Environmental Physics, Physics Institute, University of Bern
Eva Anthamatten
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Aurea C. Chiaia-Hernández
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Petra Zahajská
Institute of Geography and Oeschger Center for Climate Change Research, University of Bern
Catherine Jeandel
LEGOS, Université de Toulouse, CNES, CNRS, IRD
Krystyna M. Saunders
Institute for Antarctic and Marine Studies, University of Tasmania, Hobart
Sae Yun Kwon
Division of Environmental Science and Engineering, Pohang University of Science and Technology
Dingyong Wang
College of Resources and Environment, Southwest University
Richard Bindler
Department of Ecology and Environmental Science, Umeå University
Louise Sime
British Antarctic Survey, Natural Environment Research Council
Dominic A. Hodgson
British Antarctic Survey, Natural Environment Research Council