What is the most efficient way to add an ‘introduced’ category, if there are many species addressed? For example, the genus Opuntia should be labelled as introduced outside of America and I don’t want to do this for every species separately.
Unless you can convince the site admins to run a special job for you, I don’t believe there is any way to do it other than 1 by 1. I’m not even sure it can be done through the API if you are comfortable doing API programming - I dont see an obvious endpoint that handles it.
There must be a way, as for example the genus Drosophila is marked as introduced in NZ: https://www.inaturalist.org/observations/25153320
There is no way to validate how that got there.
There are at least 2 possibilities. There is at least 1 user who very actively manages and updates New Zealand checklist data. They may have done it manually.
The status can also be part of a bulk import of many species to a geographically based checklist, but that functionality does not help if you want to do taxonomic, not geographic based data as is the case for you.
anyway it could be very useful if it would be allowed to mark as introduced a whole genus instead of having to mark species by species. Indeed, many genera are introduced in many areas as a whole. Opuntia (together with almost all the Cactaceae) outside the Americas is well fitting.
You might find this related forum post helpful.