Detritus, trophic dynamics and biodiversity

Synthesises the structure and dynamics of food webs based on dead organic matter, and examines how detrital pathways differ from grazing pathways in their inputs, turnover and stability properties.

Studied in

Animalia, Fungi, Bacteria

Sample size

synthesis across detrital food-web studies and models

Detritus supports food webs whose dynamics differ from grazing webs in important respects: the resource does not respond to its consumers, inputs arrive independently of consumption, and the resulting couplings can stabilise or destabilise the wider community depending on structure.

• A synthesis spanning systems whose webs are described at very different resolutions.
• Stability conclusions rest partly on models whose assumptions are not settled.

• Detritus

  In most forests, the great majority of what plants make is never eaten by a herbivore. It dies, falls, and is dismantled — which is the pathway almost every food chain diagram omits.

• Detritus

  Decomposers — fungi and bacteria — break molecules apart chemically, outside their bodies. Detritivores are animals that eat dead material and make the pieces smaller, digesting little of it themselves.

• Detritus

  A rabbit population responds to being eaten. A pile of dead leaves does not. That asymmetry — a resource delivered from outside, which cannot decline in response to its consumers — changes how the whole web behaves.