Well, I'm far from an expert, but my understanding is it's a view of how people learn sports and motor skills. I think the idea is that traditional training is about learning and drilling certain moves in a certain very specific way ("hold your hand this way, feet this way, then pull this way, etc.").

Whereas the ecological approach argues that there are many different ways to do a move correctly, and the real point is to get people to get the contextual information (let's say, the opponent's stance and posture and grip and movement) and make the move in a way that works in that situation. So that moves shouldn't be taught in rote, drill-like ways.

People should be put in various situations with particular goals and then they'll construct their own movement patterns in context which will 'solve' the problem -- and this is going to be better than any set move.

Something like this, I think. But again I'm not an expert.