Complex landscapes are messy, and it’s hard to untangle which ecological processes matter most. In Fish Future’s latest paper, Jonathan Tonkin and Angus McIntosh helped show that food webs can act like a map, revealing how energy and resources move through these environments.
Using stable isotopes in a braided river, they discovered that birds, fish, and other mobile consumers rely on food sources that vary a lot across space. Their feeding patterns reflected four key food‑web features: shifting foraging over time and space, outside energy subsidies, omnivory, and changes in diet as animals grow.
Together, these patterns show that both the physical layout of the river and the flexible behaviour of consumers shape how the food web works. Understanding these hidden structures helps reveal the processes—and scales—that keep complex ecosystems stable.