The upper Columbia watershed has more ecological similarity to the upper Colorado watershed than to the lower Columbia. Consider that a relatively modest (geologically speaking) change in topology could join them into a single watershed, thus radically altering the watershed-defined "bioregion" but without fundamentally changing their ecology.So, to illustrate this, here's that classic map of the Cascadian bioregion:
Here's the Forest Service map of eco-regions, zooming into Cascadia:
This map looks much more like the coastal Cascadia map I was rooting for here.
The larger bioregional map, I think, is a much more expansionist idea of Cascadia, pushing the borders out towards where Cascadia doesn't really exist right now. Or may ever. I don't think its a coincidence that this map is also more attached to those folks that are also expressly seccesionist. These are both Cascadia's that don't yet exist.
But, I'm more worried about Cascadias that already exist, socially, politically and ecologically. Or, at Matthew would say:
I don't think it's a coincidence that the map which emphasizes human cultural similarities actually does a better job of showing ecological zones than the bioregion map does.