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Published on: July 30, 2019
Patterns and drivers of fish trophic trajectories over time
Flavien Garcia1, Julian D Olden2, Anthony Sturbois3,4
1Centre de Recherche sur la Biodiversité et l'Environnement (CRBE) - UMR 5300, CNRS, IRD, Toulouse INP, Université de Toulouse, Toulouse, France.
Global environmental change alters freshwater fish communities, shifting trophic structures. Species turnover, especially from invasive species, significantly impacts food webs and ecosystem function.
Area of Science:
- Ecology
- Environmental Science
- Aquatic Ecology
Background:
- Global environmental change causes significant upheaval in biological communities.
- Changes in community composition are documented, but shifts in trophic structure are less understood.
Purpose of the Study:
- To investigate how changes in fish community composition and environmental factors influence trophic trajectories over time.
- To analyze trophic structure shifts in freshwater fish communities using a 10-year dataset.
Main Methods:
- Utilized a 10-year dataset of freshwater fish communities from nine lakes.
- Analyzed stable isotope compositions to assess trophic structure.
- Correlated community composition changes and environmental factors with trophic trajectories.
Main Results:
- Observed significant changes in fish community trophic structure across all lakes, trending towards narrower trophic niches.
- Trophic trajectories varied among lakes, linked to the pace and direction of compositional change.
- Communities dominated by non-native species showed increased trophic stability.
Conclusions:
- Species turnover, driven by the addition/removal of predators, is the primary factor shaping trophic dynamics.
- Biological invasions play a crucial role in altering trophic niches and food web architecture.
- Understanding these dynamics is vital for predicting ecosystem functioning under environmental change.
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