Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years

Abstract Hutchison’s niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each i...

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Main Authors: Francis van Oordt, Antonio Cuba, Emily S. Choy, John E. Elliott, Kyle H. Elliott
Format: Article
Language:English
Published: Nature Portfolio 2024-04-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-024-57339-w
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author Francis van Oordt
Antonio Cuba
Emily S. Choy
John E. Elliott
Kyle H. Elliott
author_facet Francis van Oordt
Antonio Cuba
Emily S. Choy
John E. Elliott
Kyle H. Elliott
author_sort Francis van Oordt
collection DOAJ
description Abstract Hutchison’s niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach’s storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ 15N and δ 13C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ 15N [baselines], PC2 of δ 15N [trophic position], PC1 and PC2 of δ 13C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon–nitrogen biplots.
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spelling doaj.art-133b78d3b1d7416587027a01230f4fc92024-04-07T11:15:59ZengNature PortfolioScientific Reports2045-23222024-04-0114111210.1038/s41598-024-57339-wAmino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 yearsFrancis van Oordt0Antonio Cuba1Emily S. Choy2John E. Elliott3Kyle H. Elliott4Department of Natural Resources Sciences, McGill UniversityInstituto del Mar del PerúBiology Department, McMaster UniversityScience & Technology Branch, Environment and Climate Change CanadaDepartment of Natural Resources Sciences, McGill UniversityAbstract Hutchison’s niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach’s storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ 15N and δ 13C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ 15N [baselines], PC2 of δ 15N [trophic position], PC1 and PC2 of δ 13C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon–nitrogen biplots.https://doi.org/10.1038/s41598-024-57339-w
spellingShingle Francis van Oordt
Antonio Cuba
Emily S. Choy
John E. Elliott
Kyle H. Elliott
Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
Scientific Reports
title Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
title_full Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
title_fullStr Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
title_full_unstemmed Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
title_short Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
title_sort amino acid specific isotopes reveal changing five dimensional niche segregation in pacific seabirds over 50 years
url https://doi.org/10.1038/s41598-024-57339-w
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