The particular way that components are connected is one of the features that distinguish an Ecosystem Model from the more familiar and commonly used Conceptual Diagram (sometimes referred to as a “concept map”). In an Ecosystem Model, the connections between component parts always represent the movement (or flux) of nutrients or energy among components, while in a Conceptual diagram the connections between the ecosystem components may illustrate many different ways in which these components are related to each other.
For example, in a Conceptual Diagram connecting trees to people, it makes sense that people use lumber from trees. However, from the perspective of an ecosystem model, no transfer of energy or nutrients has occurred between the trees and people, because the nutrients & energy are still in the tree (lumber).
In an Ecosystem Model connecting people and trees, the connection must be one that actually transfers nutrients or energy from one component to the other. For example:
People harvesting timber or “using timber” does not move energy or nutrients into the people. But, when people EAT something from a tree, like maple syrup, then energy & nutrients are transferred from the tree component to the people component.