Interdecadal changes in at-sea distribution and abundance of subantarctic seabirds along a latitudinal gradient in the Southern Indian Ocean

• Published in: Global Change Biology
• Main Authors: Peron, C, Authier, M, Barbraud, C, Delord, K, Besson, D, Weimerskirch, H
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2010
• Subjects: Environmental Sciences; Ecological Applications; Ecological Impacts of Climate Change; Antarctic; Indian; Southern Ocean; Antarc*; Diomedea exulans; Giant Petrels; Wandering Albatross
• Online Access: https://doi.org/10.1111/j.1365-2486.2010.02169.x; http://ecite.utas.edu.au/92768

Long-term demographic studies have recently shown that global climate change together with increasing direct impactsof human activities, such as fisheries, are affecting the population dynamics of marine top predators. However,the effects of these factors on species distribution and abundance at sea are still poorly understood, particularly inmarine ecosystems of the southern hemisphere. Using a unique long-term data set of at-sea observations, we tested forinterdecadal (1980s vs. 2000s) changes in summer abundance and distribution of 12 species of Albatrosses and Petrelsalong a 30 latitudinal gradient between tropical and Antarctic waters of the southern Indian Ocean. There werecontrasting effects of climate change on subantarctic seabird distribution and abundance at sea. While subtropicalwaters showed the highest rate of warming, the species that visited this water mass showed the greatest changes indistribution and abundance. The abundance of Wandering Albatrosses ( Diomedea exulans ), White-chinned Petrels( Procellaria aequinoctialis ) and Giant Petrels ( Macronectes sp.) declined markedly, whereas the other species showedcontrasting trends or did not change. With the exception of the White-chinned Petrel, these decreases were at leastpartly related to regional increase in sea surface temperature. The southward shift of Wandering Albatross and Prions( Pachyptila spp.) distributions could be ascribed to species redistribution or decrease in abundance due to warming ofthe subtropical waters. Surprisingly, White-chinned Petrel distribution shifted northward, suggesting more complexmechanisms. This study is the first to document a shift in species range in the Southern Ocean related to climatechange and contrasting abundance changes. It suggests that some species might experience more severe impacts fromclimate change depending on the water masses they visit. As climate changes are predicted to continue in the nextdecades, understanding species responses to climate change is crucial for conservation management, especially whentheir conservation status is critical or unknown.