Food-web structures link multi-scale processes in complex landscapes

Area of Science:

• Ecology
• Environmental Science
• River Ecosystems

Background:

• Studying complex landscapes is challenging due to simultaneous high-level contextual and low-level mechanistic processes.
• Food-web structures offer insights into these processes within specific ecological contexts.

Purpose of the Study:

• To use stable isotopes to identify spatially distinct resources and infer resource flows in a braided river food web.
• To understand how food-web structures relate to ecological and mechanistic processes in complex landscapes.

Main Methods:

• Stable isotope analysis to trace resource use by mobile consumers (birds, fish).
• Identification of spatially heterogeneous resources within a braided river system.
• Analysis of consumer resource use in relation to food-web structural attributes.

Main Results:

• River resources utilized by mobile consumers were found to be spatially heterogeneous.
• Consumer resource use correlated with spatiotemporal foraging variation, subsidies, omnivory, and ontogenetic niche shifts.
• Both physical landscape heterogeneity and consumer adaptive traits influence food-web structures.

Conclusions:

• Complex river food webs are shaped by interactions between physical landscape context and consumer adaptations.
• Analyzing food-web structures across scales of resource use and distribution aids in identifying stabilizing processes.
• This approach provides a framework for understanding ecosystem dynamics in heterogeneous environments.