When field guides fail

Increasingly identification to a species level is requiring either microscopic, or even molecular level investigation. Or in the case of rodents an ability to look into their mouths and study their dental patterns, don’t recommend trying that with a live vole, can’t even picture it with a carnivore.

The point is if it is a microscopic examination of a bryophyte, or the need for a molecular examination of a mushroom it is not something most naturalists can do in the field. If the organism being identified is in a new taxon to the identifier they may not realize that the trusted, dog eared guide is facing becoming obsolete?

How should people be made aware that you can nolonger use visual identification with certain groups? Had I not spent a summer looking at the achenes of sedges with a microscope, I would have felt I could identify them in the field.


Maybe a setting could be set at the taxon level, saying “This species can’t usually be identified visually; unless you have further information, consider leaving the ID at the genus level” or something to that effect?

I was wondering the other day how long it’ll take until “take a photo” gets replaced by “take a DNA sample”, at least for stuff like plants…


My long-time fantasy has been to have tiny handheld DNA scanners that you can just blip a plant with and upload the species straight away. It’d be so cool!


Visual identification has always been tough with certain groups and no field guide has ever been 100% reliable in IDing certain species. And photos have never really been adequate for some organisms, unless you’re able to get macro shots of certain subtle characteristics. Even then, it won’t work for some creatures unless you have a dead specimen in hand (e.g., many rodents).

But there’s still a place for field guides, even if genomic research has resulted in the recognition of new species that look a heck of a lot like one or more other species. Sometimes you might have to lean a lot on location if the geographic distributions have been worked out.

The rampant taxonomic splitting that we are seeing now in many groups of organisms, based on biomolecular studies, might be going a little too far in many cases. Some correction of that may be coming in the future. Don’t throw away your field guides yet.


I wish for one of those hand held instant DNA scanners everyday. Perhaps they are actually not too far off.


The main fault of field guides in many tropical areas is their non-existence.


Apparently, some people are already using something similar:



Couldn’t agree more. Here in Indonesia they are very much lacking especially for invertebrates (except for butterflies and dragonflies).


Can‘t agree more with this. In lichens, I‘ve seen so many splits during the last twenty years. Many of which did not survive even several years.

Again, I agree that there are many species that can’t be identified from a photo. For lichens more than often microscopy and/or chemistry are necessary. And by chemistry I mean thin layer chromatography, not just spot tests. However, even in lichenology field books would be still useful for the naturalists, but they should be produced in different way than they used to be. And, which is even more important – they should be regional. For example, Eastern Europeans will have little use of, say, British guide and vice versa. I won’t even start about the total lack of field guides outside Europe and NorthAmerica. It is a disaster. Research (or rather these who make decisions in financing research) should make serious effort in producing guides (printed and internet-based).


Also see this thread: https://forum.inaturalist.org/t/the-future-of-dna-barcoding-and-its-use-in-citizen-science/2681


There is another aspect of this question, when we talk of citizen science who are we addressing? A handheld DNA barcode devise is likely in academe, but is a critical part of projects like iNaturalist not involving more people, alibet “untrained” people in the natural world?

I sit here with five different state flora’s that many people I meet in the woods would not be able to read, they have not been forced to learn the botanical language. Yet if diversity is to be valued do we not need to expand “the choir”?

Do we need to develop a multilevel system, with “DNA verified” as a possible tag? I would hate to see people stop taking observations because they felt inferior.


The only changes to the system that I think might possibly help this problem are being able to flag taxa to indicate that they are difficult to ID to species without special techniques and changing how “Based on the evidence, can the Community Taxon still be confirmed or improved?” works. Otherwise all we can do under the current system is become more knowledgeable, make IDs at higher taxonomic levels, check the “can the community taxon still be improved?” box, and add explanations for why we feel it cannot be determined to species.

This notion that every observation should be identifiable to species or it isn’t worth putting on iNat that some people have is unfortunate. I put up plenty of observations where I don’t even know what Kingdom the organism is in, and sometimes even if it is a living thing or not. Any ID that can improve on that helps me out and is why I use iNat, even if it’s at a very high level.


My hope with iNat is that the computer vision will someday get good enough to pick up on a large number of morphological characters that aren’t easily described in the text of a key, but that when considered en masse can confidently identify to a fine taxonomic level. For example, technical works in mosses rely heavily on microscopic characteristics in their keys. But if enough people eventually upload observations of identified specimens that include a macroscopic shot perhaps we can train the CV to pick up on visual features at the macroscopic level, like the shape and apparent textures of the mosses. Things like texture and patterning are difficult to describe (doesn’t stop us from trying of course - see the expansive technical vocabulary for describing plant organ vestiture) but the CV doesn’t need jargon, it just needs visual features.

I’d push back strongly on the comments here that imply that “molecular” splitting work is somehow undesirable. Species designations are hypotheses about population interactions: future, present, and historical. Of course genetic evidence is germane to informing those hypotheses. In many cases, it’s the only thing bringing us out of the dark ages when differences of opinion in species delineation had more to do with the social status of the author than, you know, actual evidence…


I agree it’s a useful tool and more reliable than other methods based on morphology and opinion of the taxonomist (although the latter still plays a role). However some of the biomolecular studies might be overshooting the mark in certain cases, splitting species that have not yet been fully evaluated in terms of actual genetic isolation between forms. What we call a species has evolved over time, so there’s still an element of arbitrariness in where we draw the line. For some taxa, the pendulum might have swung too far towards the splitters and I expect we’ll see some re-lumping in the future to bring it back. As you say, taxonomy consists of hypotheses about relationships. As such it’s never really stable.



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I can see that clearly in Lepidoptera, where the undistiguishable species are usually neglected. People in the field lose all interest in Oligia, Hoplodrina or Caradrina species, for example, because they know up-front, a photo will not get to the species! There is a certain “frustration” in the system because higher taxa cannot get research grade, or only manually. But I guess it is in the nature of taxonomy to live with ever changing names, genus affiliations and new sister species. Looking at the European Lepidoptera species using https://www.inaturalist.org/observations?place_id=97391&subview=grid&taxon_id=47157&view=species will happily ignore all the “difficult” genera.


Good point - one thing that should be more clearly explained to non-biologists is that the concept of “what is a species” is very slippery and in many cases a handy convenience rather than particularly meaningful. Often genus-level is good enough.


I feel a pang of anxiety when I see field guides to fungi using watercolour paintings alongside mention of their edibility / toxicity.


Agree. I think part of the problem is the term “Research Grade”. It would be nice if certain taxons could become Research Grade without making it to species level. Maybe different types of “Research Grade” attributes.


Some observations can already become Research Grade at a level higher than species: https://forum.inaturalist.org/t/family-and-genus-level-ids/4083 Are you proposing that there should be a list of taxa at higher levels for which this is done automatically without having to use the Data Quality Assessment box?

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