Bottom-up control models assume:
“Unidirectional flow from primary producers” for bottom-up control models assume. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. The relevant inference should follow the pathway from resource supply to organismal uptake and then to ecosystem-level flux. Productivity, trophic transfer, decomposition, and nutrient regeneration are connected, but each measures a different part of that pathway. The remaining alternatives—“Bidirectional energy flow”, “Unidirectional flow from top predators”, “Trophic
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
