Feels like xena_allen is right about the lack of real reasons. It's often just for short-term cash that ignores the long-term value of these living things. That shortsightedness is the much bigger problem.
My town just paved over the little creek park to put in more storage units. Same deal. @xena_allen has a point about the "reasons" being weak. They said it was for "storm drainage," but we all know it was a cheap lot some developer grabbed. Reminds me of when they knocked down the old diner for another chain pharmacy. Everything solid gets traded for fast money now.