Participant ecology is the effective world a person actually inhabits: the subset and configuration of the shared field ecology that is functionally reachable, consequential, or active for them. It is the level at which the model’s developmental concern lives, because it is where two people diverge inside the same place.
Two children grow up in the same city, under the same government, in the same decade. One has parents who travel, access to international people, books, museums, money, and broad networks; the other does not. Same formal society — different participant ecologies.
What configures it is not geography but resources, connections, standing, signal access, interior realities, pathways, and developmental history. This is why a single metric like income reveals so little: it reads a sliver of one participant ecology and is silent on the relational, informational, and standing structure that actually decides what the field can do for that person. Development, in these terms, is partly the widening of a participant ecology toward the latent ecology around it. See Whose Ecology?.