I believe the observation part should record the "nativeness" of the habitat, not of the species. An animal in a zoo or plant in a botanical garden is likely to be non-native - but it could be. A lichen or a pathogenic fungus is much more likely to be native. But knowing the habitat according to this, would be very useful for pathogenic funguses as well.
With limited nativeness to English, nativeness applied to habitat does not seem to be the correct term to me, establishment means neither.
--------------- Any additional proposal for a term recording the occurrence circumstances with respect natural or man-made? ---------------
Proposals for terms to be covered could be:
Inside a building; including greenhouses (= square kilometers of these in agriculture!) Open air garden or zoo Open agricultural habitat High volume traffic lines (railways, highways, waterways) Habitats with limited human influence.
to be emended and improved....
This list is among other informed, by questions in quarantine, but also escaping biologically modified organisms.
Gregor