Trophic complexity of small fish in nearshore food webs

Holly A. Wellard Kelly, Katya E. Kovalenko, Tyler D. Ahrenstorff, Bethany J. Bethke, Valerie J. Brady, Joshua D. Dumke, Gretchen J.A. Hansen, Heidi M. Rantala

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Small nearshore fishes are an important part of lacustrine and functional diversity and link pelagic and benthic habitats by serving as prey for larger nearshore and offshore fishes. However, the trophic complexity of these small nearshore fishes is often unrecognized and detailed studies of their role in food webs are lacking. Here, we examined niche space patterns of small nearshore fish species using Bayesian analyses of carbon and nitrogen stable isotope data in nine freshwater lakes that are among the largest lakes in Minnesota. We found considerable variability in niche areas within species and high variability in niche overlap across species. At the assemblage level, niche overlap (average diet overlap of all species pairs at a lake) decreased as whole-lake species richness increased, possibly indicating a greater degree of resource specialization in more speciose lakes. Overall fish niche space was weakly but significantly related to niche space of their invertebrate prey. Although nearshore benthic resources contributed to fish diets in all lakes, all fish species also had non-negligible and variable contributions from pelagic zooplankton. This inter- and intraspecific variability in trophic niche space likely contributes to the multi-level trophic complexity, functional diversity, and potentially food web resilience to ecosystem changes.

Original languageEnglish (US)
Pages (from-to)2505-2521
Number of pages17
Issue number10
StatePublished - Apr 8 2021

Bibliographical note

Funding Information:
We thank Jaime LeDuc, Ryan Maki, Will French, Robert Hell, Matthew Santo, and Jodie Hirsch for field and laboratory assistance. We also acknowledge Minnesota Department of Natural Resources staff who collected and processed samples used for this analysis. We thank the editor and two anonymous reviewers for suggestions that greatly improved the manuscript. This paper is contribution number 640 from the Natural Resources Research Institute-University of Minnesota Duluth (NRRI-UMD).

Funding Information:
Funding for this research was provided by the Minnesota Environmental and Natural Resources Trust Fund as recommended by the Minnesota Aquatic Invasive Species Research Center (MAISRC) and the Legislative-Citizen Commission on Minnesota Resources (LCCMR), and NRRI-UMD.

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.


  • Functional diversity
  • Macroinvertebrates
  • Niche overlap
  • Niche space
  • Stable isotopes


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