I haven't had enough game time with this tech-branch in play, but I'm wondering about why it seems that the lower-level tile improvements either disappear or are never present later in a game or when I conquer a world held by a non-amphibious species.
It seems to me that after a game enters the last tech era, I should see all three additional tile reclamation options on any world I colonize, and maybe any world that I conquer/flip from another species without the aquatic biospheres option.
What am I misunderstanding or failing to observe?