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Climate oscillation and the invasion of alien species influence the oceanic distribution of seabirds    
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  • Julian Perez-Correa,
  • Peter Carr,
  • Jessica Meeuwig,
  • Heather Koldewey,
  • Tom Letessier
Julian Perez-Correa
Imperial College London, London, United Kingdom , Escuela de Ciencias Ambientales, Facultad de Ingeniería, Universidad Espíritu Santo, Samborondón, Ecuador, Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
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Peter Carr
Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall, UK, Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
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Jessica Meeuwig
Centre for Marine Futures, Oceans Institute and School of Animal Biology, The University of Western Australia, Crawley, WA, Australia
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Heather Koldewey
Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall, UK, Conservation and Policy, Zoological Society of London, Regent’s Park, London, UK
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Tom Letessier
Centre for Marine Futures, Oceans Institute and School of Animal Biology, The University of Western Australia, Crawley, WA, Australia , Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK
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Abstract

Spatial and temporal distribution of seabird transiting and foraging at sea is an important consideration for marine conservation planning. Using at-sea observations of seabirds (n = 317), collected during the breeding season from 2012 to 2016, we built boosted regression tree (BRT) models to identify relationships between numerically dominant seabird species (red-footed booby, brown noddy, white tern and wedge-tailed shearwater), geomorphology, oceanographic variability, and climate oscillation in the Chagos Archipelago. We documented positive relationships between red-footed booby and wedge-tailed shearwater abundance with the strength in the Indian Ocean Dipole, as represented by the Dipole Mode Index (6.7% and 23.7% contribution respectively). The abundance of red-footed boobies, brown noddies and white terns declined abruptly with greater distance to island (17.6%, 34.1% and 41.1% contribution respectively). We further quantified the effects of proximity to rat-free and rat-invaded islands on seabird distribution at sea, and identify breaking point distribution thresholds. We identified areas of increased abundance at sea and habitat use-age under a scenario where rats are eradicated from invaded nearby islands and recolonised by seabirds. Following rat eradication, abundance at sea of red-footed booby, brown noddy, and white terns increased by 14%, 17% and 3% respectively, with no important increase detected for shearwaters. Our results have implication for seabird conservation and island restoration. Climate oscillations may cause shifts in seabird distribution, possibly through changes in regional productivity and prey distribution. Invasive species eradications and subsequent island recolonization can lead to greater access for seabirds to areas at-sea, due to increased foraging or transiting through, potentially leading to distribution gains and increased competition. Our approach predicting distribution after successful eradications enables anticipatory threat-mitigation in these areas, minimising competition between colonies and thereby maximising the risk of success and the conservation impact of eradication programmes.  

Peer review status:ACCEPTED

30 Jan 2020Submitted to Ecology and Evolution
31 Jan 2020Submission Checks Completed
31 Jan 2020Assigned to Editor
31 Jan 2020Review(s) Completed, Editorial Evaluation Pending
04 Feb 2020Editorial Decision: Revise Minor
30 Jun 20201st Revision Received
01 Jul 2020Submission Checks Completed
01 Jul 2020Assigned to Editor
01 Jul 2020Review(s) Completed, Editorial Evaluation Pending
10 Jul 2020Editorial Decision: Accept