If Life is Meaningless Anyway, then What's Wrong with Religion?

[The Grand Nudger]

Do you think we're unique in that the ecosystem would go on without us?

No.

I think we're unique in the way that without us, the ecosystem would improve.

That's a common belief.  The ecosystem would change, whether or not that change is an improvement would be an issue of perspective.  It wouldn't be an improvement for our pets, our livestock, or the species which flourish in our wastes or directly because of our many and varied activities.  

For example, as you may know I do a little bit of fishing once in a while up in Alaska. The department of fish and game has resorted to constructing platforms along certain rivers to keep people from walking directly on the banks because it's detrimental to the habitat of baby salmon, which use the vegetation along the banks as a food source and shelter from predators.

I'm not sure why you think this would be an example of the above.  We manage our wildlife resources.  Why do you not see -this- as a role that human beings play in the ecosystem? Human beings are, in your example...improving the ecosystem, by the metrics you seem to be using for improvement. We do this intentionally and unintentionally for a variety of species. Animal husbandry and livestock production started out this way. It was wild herd management before we built the fences. We would improve the ecosystem for them (and they would in turn improve it for us). Your example, notably, regards a commercially fished species. You don't see much ecosystem improvement for the benefit of non-marketables. In this regard, we're doing pretty much the same thing we've always done..but why it's improvement in this case and not improvement in the case of cattle, in your estimation, is beyond me.

I think, and correct me if I'm wrong, but I think it boils down to a perception of artificial ecosystems as artificial in the sense of being fake, "not really the ecosystem"...and that in turn reduces to a misunderstanding of the term artificial. We use it to mean fake, but in context it merely refers to artifice. Things we make. Those things are, themselves, ecosystems by definition.