Interspecific Interactions Constrain Individual Niche Divergence and Reveal Energetic Cost of Niche Expansion
- 1Great Lakes Research Center Michigan Technological University Houghton Michigan USA
- 2Department of Biological Sciences, Advanced Environmental Research Institute University of North Texas Denton Texas USA
Abstract
Individuals vary in resource use, generating trophic niche variation that shapes a population's niche width (PNW). Interspecific interactions are predicted to constrain PNW, though individual responses are often heterogeneous. The keystone niche individual (KNI) framework identifies individuals that disproportionately expand PNW by exploiting resources beyond the population's realized niche, but whether interspecific interactions limit their emergence is unknown. We tested this by comparing an allopatric and sympatric population of brook trout ( Salvelinus fontinalis ) and rainbow trout ( Oncorhynchus mykiss ). Fatty acid profiles from repeatedly sampled individuals were used to quantify individual trophic niches and their contributions to PNW. Individuals in sympatry exhibited more negative contributions to PNW (−2.70% ± 1.7%) than individuals in allopatry (−0.47% ± 1.8%) and showed a continuum of contributions rather than discrete KNI, indicating that interspecific interactions constrained niche expansion by reducing disproportionate contributions to PNW. Across both populations, individuals with greater contributions to PNW exhibited reduced trophic overlap with competitors and lower body condition, revealing energetic costs of niche expansion. These findings suggest that, in this study system, interspecific interactions can limit niche differentiation by reshaping how individuals contribute to population‐level trophic diversity, highlighting the need to evaluate the generality of these mechanisms across ecological contexts.
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BibTeX
@article{roose2026interspecific,
title = {{Interspecific Interactions Constrain Individual Niche Divergence and Reveal Energetic Cost of Niche Expansion}},
author = {Hunter C. Roose and James R. Junker and Jill A. Olin},
journal = {Ecology and Evolution},
year = {2026},
month = nov,
doi = {10.1002/ece3.74619},
url = {https://onlinelibrary.wiley.com/doi/10.1002/ece3.74619},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Interspecific Interactions Constrain Individual Niche Divergence and Reveal Energetic Cost of Niche Expansion
AU - Hunter C. Roose
AU - James R. Junker
AU - Jill A. Olin
PY - 2026
DA - 2026/11/02
JO - Ecology and Evolution
DO - 10.1002/ece3.74619
UR - https://onlinelibrary.wiley.com/doi/10.1002/ece3.74619
AB - Individuals vary in resource use, generating trophic niche variation that shapes a population's niche width (PNW). Interspecific interactions are predicted to constrain PNW, though individual responses are often heterogeneous. The keystone niche individual (KNI) framework identifies individuals that disproportionately expand PNW by exploiting resources beyond the population's realized niche, but whether interspecific interactions limit their emergence is unknown. We tested this by comparing an allopatric and sympatric population of brook trout ( Salvelinus fontinalis ) and rainbow trout ( Oncorhynchus mykiss ). Fatty acid profiles from repeatedly sampled individuals were used to quantify individual trophic niches and their contributions to PNW. Individuals in sympatry exhibited more negative contributions to PNW (−2.70% ± 1.7%) than individuals in allopatry (−0.47% ± 1.8%) and showed a continuum of contributions rather than discrete KNI, indicating that interspecific interactions constrained niche expansion by reducing disproportionate contributions to PNW. Across both populations, individuals with greater contributions to PNW exhibited reduced trophic overlap with competitors and lower body condition, revealing energetic costs of niche expansion. These findings suggest that, in this study system, interspecific interactions can limit niche differentiation by reshaping how individuals contribute to population‐level trophic diversity, highlighting the need to evaluate the generality of these mechanisms across ecological contexts.
SN - 2045-7758
SN - 2045-7758
ER -