In the past if there were no creatures spawning before there should be no creatures spawning after you terraformed and built structures. Plants, landscaping, buildings &c. do not influence creature spawns. The only thing that influences creature spawns are most fire sources, workbenches & wards, and they are used to suppress spawning where creatures had been known to spawn prior.

That being said, I have noticed spawning & spawn rates seem to have changed since a recent patch. Now it appears that creature spawn is connected to player proximity and activity. Late last year I placed some packs of tamed wolves outside our headquarters as an early defensive measure against invasion events. I know for a fact that in most of the areas I placed them boar & deer previously had no presence, now they are spawning like crazy and in numbers that are unprecedented. The more time I spend outside and the longer I am active the more deer and boar spawn. There was a time when I would not even notice my wolf packs were outside other than hearing the howls of wolf cubs after I had fed my wolves. Now when I visit HQ I constantly hear the death cries of deer and boar outside. For a month or two after I placed the wolf packs outside their numbers did not noticeably increase. Now there are rife throughout the area as they are feeding themselves from all the deer and boar that are spawning in their locations.