But a good or bad disruption? Are you arguing that the ecosystem is currently optimal? It seems unlikely. So there's interesting questions; what's an optimal ecosystem look like? How can it be achieved?
Industrialized humans have a historically abysmal track record of ham-fistedly “optimizing” ecosystems.
Any manual intervention into an ecosystem generally requires establishing an indefinite commitment to more manual maintenance.
Who determines what “optimal” means? Who implements the optimization? Who pays for it? What happens in a few decades when people lose political interest in the project? Which creatures do we optimize for? Why are we doing this at all? How have similar projects fared in the past?
I can tell you haven’t seriously studied ecology from the way you are approaching this question, so I’m not too worried. But consider questions like those as you ponder this scenario.