I did try to start a discussion on this a few months ago alongside another establishment idea I had (https://forum.inaturalist.org/t/reintroduced-and-self-introduced-establishment-means/3437), but the discussion was dominated by the “self-introduced” idea, with nothing about the “reintroduced” category, so I’ll make a suggestion post just for this one.
Might it be possible to create a “reintroduced” establishment category for plants / animals that have been reintroduced to an area they were extirpated from? The reason I suggest this category is because I think it would be good practice to indicate that just because an organism is present and native to a certain locality doesn’t mean that it has always been there in the immediate past. For example, a foreign user looking at the American Bison distribution map may assume that most of the localities east of the Rockies are home to relict populations of bison when in actuality, their populations were reintroduced from surviving bison herds in the Rockies and westward.
In addition, reintroduced animals can be of much different genetic origin than the former residents of the area. For example, the yellow-crowned night-herons on Bermuda were reintroduced to take the place of the extinct Bermuda night-heron, which was a completely different species in the same genus. But if one didn’t hear about the reintroduction and looked at the range map, they might assume the night-heron population on Bermuda to be an isolated population that naturally colonized the area after being blown in by storms. Thus, adding a symbol for a reintroduced taxon can educate users about how animal populations can be reestablished by human effort, and also indicate that the population currently present is not the same as the one in the past.
Unlike other establishment categories, this one could also be compatible with other establishment means (i.e. the red wolf is an endemic species to the US but has been reintroduced to NC, so an observation would have both the green star icon and the reintroduced one).
My suggestion for the "“reintroduced” establishment icon on an observation would be a white cross on a blue background (something like this). I suggest this because blue isn’t a color that has been used by these icons yet, and the cross is a frequent symbol of first-aid (much like how reintroduction is basically first-aid for a species’s survival chances). Of course, I do understand it looks a bit like the Greek flag.