I think I agree with and support what @jdmore is suggesting here.
Also, what authorities does iNaturalist use for determining native vs. introduced status? Are there any guidelines of how to determine this?
I have noticed that there can be significant disagreement about this stuff. It is not something I would want to leave to being edited by individual users, because talking to the average gardener, they have a lot of misconceptions about what is native and introduced in which regions. For example, just today I heard someone say Virginia creeper was an invasive species in PA, and I frequently hear people say that introduced plants are “native”. I feel like allowing or encouraging users to edit this stuff directly could be a huge can of worms if there were not some sort of fairly strict guidelines that were clearly spelled out, and some sort of checks about it.
For plants, I trust the data provided by BONAP more than the USDA. I have not found a source more extensive or accurate than BONAP, but I recognize that it also has its limitations. For plants in PA, I also use the Plants of Pennsylvania book by Rhoads and Block which also has more accurate information about this stuff.
To respond to @pisum, here is the BONAP map on sweetgum, and it shows it native everywhere including through Houston, which is at the border of its range, and introduced (they call it “adventive” which I think is the category they use across the board for things native to the continent but not the local area) only on the West Coast and one county in NE Massachussets.
I find it odd that iNaturalist would flag sweetgum as non-native in Houston, but it seems to list records in California as native when it is clearly introduced there.
I also am curious about how iNaturalist defines or draws cutoffs about something being introduced. And does it have (or are there any plans for it to have) more categories than just introduced and native, sort of the way BONAP has “adventive”? One thing I don’t like about BONAP is that they don’t distinguish things like…in that sweetgum exmaple, they mark the county in NE Massachussets “adventive” but also mark the introductions of that species to the west coast, by the same category. Ecologically, it seems different, because it’s separated by a massive geographic aree and is a totally distinct ecoregions, vs. being a few counties displaced from native population, in a more-or-less similar ecoregion.