My colleague Chris Buddle has asked an interesting and important question about taxonomic descriptions and natural history data. Specifically: Should taxonomists wait to describe a species until there are some details known about its natural history? Chris and I both cross the line between taxonomy and ecology frequently in our research and teaching, so I suppose these links between taxonomy and natural history are on our minds a lot.
My short answer to Chris’s question is: No.
Here’s my long answer, from my (mostly) taxonomist’s perspective:
Big questions, small steps
Most new species of arthropods and other small organisms are recognized from specimens already preserved in natural history collections, not collected as part of focused hunting expeditions (Another nature documentary myth deflated. Sorry). This means that a taxonomist will often describe a new species based on a few dead specimens, and a very small label with minimal data. Here’s an example of the challenge that can create: I have a specimen of a (likely) new species of fly sitting by my microscope. The label reads: “CAN:YT: Dempster Hwy nr North Fork Pass 64.57942° -136.28212°, 1200m, Repl. 3 wet, sweep, 24.vi.2012, NBP field party”. And because I was the NBP field party member who did the sweep transects that day I have a little more detailed memory about the vegetation and topography along that transect. But I don’t know where along that transect I got that specimen. In a large scale study, with lots of field sites and sample grids and lots of data to collect in a very short time we simply do not have the ability to note each of those specimens when they’re alive and watch what they’re doing. It would be great fun to do so, but neither I, nor any of the students, would get enough data to finish any of our projects. This is the trade-off, especially when we’re working on small and obscure arthropods as part of a big and ambitious project.
I’ll almost certainly describe that new species because I think it’s an interesting little fly in a distinctive genus in a part of the world where I would not have expected to find it. And I know from the label where and when I collected it. But that’s hardly significant “natural history information”. I don’t know where along that gentle slope above a tundra pond I got that fly as I swept. The sedge hummocks? beside the Dryas? under the little shrub? out of mid-air? And I certainly don’t know what it eats, or where its larvae develop, or its preferred microhabitat, or its role in food webs. We may never know that. I can make a prediction based on what I do know about its related species, but even there I have some nagging questions. But if I describe this species and give it a name and mark a place for it in the Great Filing Cabinet of Life, it makes it easier for somebody with an affinity for small flies and some time to kill to know that there’s a neat little question waiting to be tackled the next time they venture up the Dempster Highway. If this fly has a name, and is placed in a classification, then at least we know that its natural history is a “known unknown” (it’s sublimely comforting to know that a silly catchphrase will likely be Donald Rumsfeld’s only lasting legacy to the world).
The way we collect
One of the biggest changes in recent decades in the way we accumulate biodiversity data about arthropods is the widespread adoption of high-yield, replicated, passive collecting methods such as Malaise traps, canopy fogging and large pan trap grids. This brings in a lot of new species and a lot of material in quantities suitable for rigorous statistical analyses. The downside is that such methods have the ability to separate the collector from the live specimen in a way that was quite uncommon a century ago. In most cases we don’t see the specimens until they’re already dead and preserved. Sometimes the taxonomic expert who recognizes the species wasn’t even in the field where the material was collected. That’s not necessarily a bad thing; it’s just a thing. But it means that natural history observations about living specimens don’t always make it into somebody’s field notebook.
I’m sometimes envious of colleagues who hand-collect their specimens and make notes on them as they go, and rear them out individually to associate larvae and substrates and adults. But on the other hand, oh boy do I ever have a mountain of data!
One impediment is enough
Much has been written about the “taxonomic impediment” — the realization that there are not enough active taxonomists, and not enough resources, to describe earth’s biodiversity anywhere near soon enough, at the rate we’re going. Just here in the cabinets in my lab I have at least 200 undescribed species of small flies that I already know are new species. How many of them do I have reasonable natural history information for, beyond simply where and when they were collected? About a half-dozen. Now, I feel I have a responsibility to the scientific community to execute my duty as a duly-apprenticed, trained and employed taxonomist to get some names on those species, and in doing so, make that taxonomic knowledge about those species available for other researchers who may or may not be taxonomists. But if I only describe the species for which I have decent natural history data, I will likely describe 6 or 8 species in the next few years and let the rest sit undescribed in the cabinets. If I do that, then I will, at the end of my career, consider myself a pretty poor taxonomist. I suppose this is the cost of specializing on a group of small, cryptic, poorly-known flies, whose ecological diversity is so high that it’s hard to even predict the habits of unknown species — natural history data is sometimes a luxury.
A losing battle?
Chris asks “whether seeking additional natural history information about species (when it is described) is a losing battle… and whether this task should be in the hands of the individuals who describe species.”
I think that no battle in which our goal is greater taxonomic resolution and more complete natural history knowledge is a losing battle. If it is, I’ll go down swinging. Granted, it’s not an easy battle and it’s going to be a long one and I think we have to be content with little gains of a few inches here and there rather than total victory. We can certainly seek additional natural history information about species, and there’s little I enjoy more on a field trip than spending time just watching insects live their lives and documenting that. But in this battle, I’m a taxonomic specialist, and I will often have to choose my targets. So I’ll charge into the lines of undescribed species and worry about cleaning up the rest later.
I certainly don’t think the task of documenting the natural history of new species should rest solely in the hands of the people who describe the species (although some of the most superb naturalists I know are taxonomists). If, when I describe a species, I have that information, then I’ll put some natural history notes into the paper (but that’s rare). I won’t likely have accumulated all that knowledge myself. The best example I can think of to illustrate the power of collaboration on documenting natural history of new species is my own experience with BugGuide, where I’ve contributed taxonomic expertise to put names on a few species of flies for which other contributors (mostly non-scientists, and not taxonomists) have provided fantastic natural history data. And I know that at least a couple of those species are as yet undescribed. The more collaborations we have like these, the better.
The elephant in the room
The critical topic we haven’t addressed is: where and how can we publish these critically important natural history observations so they are accessible?
That’s probably a rant for another post.