Abstract
The Icy Strait of southeast Alaska, USA is an ideal system to study how ecological diversity is maintained. This area has historical ecological significance and supports diverse assemblages of fish species that are easily sampled. We used stable isotope analysis using δ13C and δ15N stable isotope ratios. Using these isotope ratios, we quantified trophic niche position, size, and overlap and compared how those trophic niche metrics varied using ecological and evolutionary perspectives. For ecological variation, mean total length, and δ13C trophic niche position has positive relationships with trophic niche size while total percent trophic niche overlap had a strong negative relationship. Niche density was also not consistent across trophic niche space, and that the highest density of individuals occupied a relatively small area of trophic niche space. We also compared how trophic niche position size and overlap varied considerably among habitat assemblages, where the pelagic habitat assemblage showed patterns more consistent with deterministic models of community assembly due to differences in trophic niche position, larger trophic niche sizes, and less overlap among species while the shallow sandy and shallow rocky habitat assemblages were more consistent with stochastic models of community assembly. For phylogenetic variation, Pacific salmon (genus Oncorhynchus) exhibited patterns more consistent with deterministic models of community assembly, while rockfish (genus Sebastes) exhibit more stochastic trophic niche metrics. Our results show how both deterministic and stochastic processes are most likely responsible for how trophic diversity is maintained. Additionally, by using position, size, and overlap of trophic niches, our results should be comparable among any system that uses δ13C and δ15N stable analysis and should be used to compare to other systems to determine how these patterns of trophic diversity are maintained in other systems.
Degree
MS
College and Department
Life Sciences; Biology
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Suchomel, Andrew D., "Food Web of Icy Strait, Alaska: Comparison of Position, Size, and Overlap of Trophic Niche Among Fish Species" (2023). Theses and Dissertations. 10498.
https://scholarsarchive.byu.edu/etd/10498
Date Submitted
2023-08-18
Document Type
Thesis
Handle
http://hdl.lib.byu.edu/1877/etd13336
Keywords
community assembly, stable isotopes, δ13C, δ15N, trophic niche
Language
english