Whether by means of the Agree button or typing in an ID yourself, you should ID something to the level of specificity that you (1) feel (for whatever reason) motivated to, and (2) are confident that the available evidence indicates is correct. The very same rules apply to the same degree to the decision of “should I ID this to genus or species” as apply to “should I ID this to species or subspecies” as apply to “should I ID this to X-rank or to just-below-x rank”.
Personally, I try to capture in my own observations the details necessary for a subspecies identification and I try to look for those details in the observations of others and ID to subspecies when I find them or to species when I don’t. Others, for a variety of reasons, choose not worry about subspecies, either in certain situations or at all. And that’s fine too.
Phytolacca americana has two subspecies: subsp. americana and subsp. rigida. If I remember right, the former occurs throughout the United States, has drooping racemes, and can get quite robust; while the latter occurs only in/around Florida, has erect racemes, and is smaller. I live in Nebraska, which is a very long distance away from Florida. When I’m ID’ing pokeweeds from my own state I look for racemes and when I inevitably find them to be droopoing, I ID them as subsp. americana. If I dont’ find racemes, I think “this is not Florida” and ID them as subsp. americana, but recognize I’m making an assumption there. (If anyone ever tells you you should never do this ever, ask them what up-to-date global monograph of all plants, or toads, or fish, or whatever the thing is, that they use, and maybe share it with me too because I’d love to use it.) Now if ever I find something that fits the description of subsp. rigida or find that it’s range has expanded to include my state or a bordering state (which I do check now and then because I’m a little obsessive), then I’ll go back and re-review my pokeweed IDs and adjust them as appropriate.
On the other hand, there are plenty of similar-looking subspecies out there with much less distance between their known ranges. In situations like that where the observation I’m ID’ing could be a look-alike subspecies that isn’t known from the local area but is known or suspected in bordering areas (I usually use state/province as my threshold), I’ll add an ID of species and explain “this is likely to be X, but could be Y, which is known nearby or suspected to be likely nearby, and you’d need this-or-that detail to confirm what you have observed here”. There are similar-looking species out there too, and again, the same rules apply no matter what rank we’re talking about.
There are some subspecies (and even species) that occur in an area together and are a real pain to differentiate because maybe you have to use some really tiny detail(s) in order to do so, or the detail you’re supposed to look for is like “what the heck does that even mean”. I’m stubborn, so I just take that as an exciting challenge, but again I only ID to the level I can confirm given the evidence available for that individual observation.
On the other hand, there are times where people-from-afar have decided something they found somewhere-not-where-I-live is a subspecies of this-or-that species which previously did not have any subspecies (besides the autonym or nominate subspecies). These I generally find hard to find information about (that is literally and linguistically accessible to me), or more frequently I am just too lazy to seek out that information, and I usually just keep on ID’ing my thing as species and move on. Or if it’s a plant family I’ve already “learned” (context: I’m learning to identify the species of plants that occur in my state family by family), I’ll take the time to track down the information about that new subspecies and incorporate that into my ID flow.
I sense the situation described in the paragraph immediately above this one is the one most similar to what you’re asking about. I usually find out about these just by coincidence. Maybe I’m working on a taxon flag or I’m typing in a species name and I notice in the drop-down menu a bunch of subspecies I’d never noticed before.
I once requested a particular way to discern what observations could conceivably be ID’d to a lower rank but it didn’t get much buy-in – see https://forum.inaturalist.org/t/make-needs-id-independent-of-both-research-grade-and-casual-statuses/.
I suspect that for your needs (granted I’m kind of making some assumptions here) one of these is going to best non-programmatic solutions that is available right now:
As Thomas has since clarified, if you subscribe to notifications for taxon changes on observations you follow, you’ll get one-and-only-one notification when a taxon change occurs for a taxon you have an active ID for, regardless of how many observations of that taxon there are in iNat or how many of them you have an active ID (of that taxon) on.
That only helps you for taxa you have ID’d though. If you want to see all of them, you’d have to regularly review taxon changes, which would probably be cumbersome considering many are likely not to be relevant to the geographic area you care about and as far as I know there’s no way to filter out taxon changes based on the geographic distribution of the underlying taxa, at least not through the user interface.
). With so many taxonomic changes happening it’s hard to keep up with the lumping and splitting at times. Though I do get annual updates from our provincial BC Conservation Data Centre (linked to NatureServe). I have 2 questions: