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Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years
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 ca...
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Published in: | Scientific reports 2024-04, Vol.14 (1), p.7899-7899, Article 7899 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | 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
15
N and
δ
13
C 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
15
N [baselines], PC2 of
δ
15
N [trophic position], PC1 and PC2 of
δ
13
C) 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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ISSN: | 2045-2322 2045-2322 |
DOI: | 10.1038/s41598-024-57339-w |