Dr. Rob Dillon, Coordinator

Monday, August 19, 2013

Delaware, and what we think we know, that we do not

Editor’s Note. This essay was subsequently published as: Dillon, R.T., Jr. (2019d) Delaware, And What We Think We Know, That We Do Not.  Pp 235 - 241 in The Freshwater Gastropods of North America Volume 4, Essays on Ecology and Biogeography.  FWGNA Press, Charleston.

Delaware, our first state, is surprisingly diverse.  Its Piedmont north is primarily industrial and urban, but there are some lovely (and surprisingly rich) rocky streams tumbling across the low fall line.  Large, prosperous farms dominate the sandy coastal plain of the south, where I was personally startled to find blackwater swamps, dominated by bald cypress.  And with the Delaware Museum of Natural History in Wilmington, the Academy of Natural Sciences 20 miles north in Philadelphia and the National Museum of Natural History 70 miles east in Washington, the state of Delaware is cradled in the greatest concentration of malacological talent in the USA, if not the world.

Should we be surprised to learn that Delaware has never seen a survey of its freshwater gastropod fauna?  Or that the systematic collections of the DMNH, the ANSP and the USNM hold but 151 lots of freshwater gastropods collected in The First State combined, under 31 nomina, 11 of which are misidentifications or junior synonyms?  It seems likely to me that this situation arises from some sort of “neglected backyard effect,” our North American imaginations so transfixed by the Brazilian Amazon and the Black Smokers of the Abyss that we tend to overlook the little creeks running through our own city parks back home.

I am now pleased to report that a remedy is at hand.  In coming months the FWGNA project will roll out a new website entitled, “The Freshwater Gastropods of the Mid-Atlantic States” which will include surveys of Delaware, Maryland, New Jersey, eastern Pennsylvania, and the West Virginia panhandle.  Our extensive original collections, sampled from approximately 144 sites spread down the 100 mile length and across the 30 mile breadth of The First State, will confirm that a fairly reliable estimate for the number of gastropod species inhabiting the freshwaters of Delaware is indeed 20, as might have been predicted from the meager museum records available.

We will be sharing much more detail about the freshwater gastropods of all the Mid-Atlantic states in the coming months.  My focus for the remainder of this essay is not on what we now know, but on what we thought we knew, that we did not.

I am not a fan of the nonprofit environmental group called, “NatureServe,” or its online database “Explorer.”  But if you were to open a new window in your web browser today (19Aug13), go to www.natureserve.org, hit that “Explorer” button on the right panel, and execute a query for freshwater snails AND Delaware, the search engine will return a list of just eight species.

This is a peculiar list.  Missing from it are the four most common gastropod species actually inhabiting the freshwaters of Delaware: Physa acuta (aka P. heterostropha), Menetus dilatatus, Ferrissia fragilis, and Lymnaea (Pseudosuccinea)columella.  All four of these species are very nearly cosmopolitan in their distribution throughout eastern North America, and simple reference to the collections of either the DMNH or the ANSP would have returned numerous Delaware records for most of them.

The NatureServe report will also include one species that our extensive field surveys of Delaware and attendant reviews of systematic collections have failed to uncover, Physa gyrina.  Populations of Physa gyrina do inhabit Ridley Creek in Delaware County, southeastern Pennsylvania, so on first reading it certainly seems possible that the NatureServe record might be bona fide.  Or might this record represent a misidentification of Physa acuta?  The DMNH collection does hold a single undated lot of P. acuta (locality just “Wilmington”) misidentified as P. gyrina.

On 28July13 I sent an email inquiry to Dr. Bruce Young, Director of “Species Science” for NatureServe, asking if he could provide a reference supporting his report of P. gyrina in Delaware.  Dr. Young replied the next day, apologizing that “for common species we do not tie specific records to individual references or museum collections.”  Ms. Margaret Ormes of NatureServe followed up with “I just looked at our database and my best guess is that it was added (as Physella gyrina) based on Burch (1989).” [1]

I do appreciate the courtesy of the NatureServe staff, but the facts are very plain and very ugly.  The mission of NatureServe is advocacy, not science, and Physa gyrina is a trash snail, and they do not care whether arbitrarily-chosen trash snails actually inhabit arbitrarily-chosen states.  The NatureServe Explorer database is a smokescreen and a ruse, designed to lend false scientific credibility to a political agenda.

Science is the construction of testable models about the natural world.  Such models need not necessarily be accurate, nor even based on reliable data.  I am not fussing here about the discrepancy between the NatureServe estimate of 8 freshwater gastropod species in Delaware, and the FWGNA estimate of 20.  Nor am I fussing about the basis of the NatureServe estimate, which is spurious.

Science will fix these things, eventually.  There are scientists who will drive 16,139 miles in a 1992 Nissan pickup, camp in the rain, and eat Dinty Moore beef stew for a week to not find Physa gyrina in Delaware.  There are scientists who will dump three years of unsorted DNREC-DWR macrobenthic samples into little Petrie dishes and squint through microscopes for hours to not find Physa gyrina in Delaware.  There are scientists who will sleep five nights on an air mattress in Alexandria to ride the orange line downtown to pull every drawer of physids out of the US National Museum to not find Physa gyrina in Delaware.  Science ultimately fixes carelessness, sloppiness, and neglect.

No, the worst thing about the Explorer database is not that it is wrong, but that it reinforces conventional ignorance, and in so doing works against the cause we all seek to advance.  Fresh young students, casting about for research ideas, will tend to assume that the freshwater gastropod fauna of North America is in some sense “known,” and divert their energies elsewhere.  A proposal to the NSF Biotic Surveys and Inventories Program will be reviewed more favorably if it is directed toward the Ubangi River than to the Nanticoke, even though the freshwater gastropod fauna of the Ubangi is better documented [2].  Reinforcement of conventional ignorance is not the main problem I have with the NatureServe organization [3], but it is certainly in the top ten.

How big is your budget, Dr. Young, and how large is your staff?  The FWGNA project has now surveyed all or part of ten states.  This we have done with no more than $5K in grant support total, over 15 years.  Those 16,139 miles we drove in 2012-13 were unreimbursed.  We have paid $49/night out of our own pockets to sleep on air mattresses in Alexandria.  We bought our own Dinty Moore.

I will end this essay, however, on a note of hope.  Despite the layers of pseudoscientific hoo-hah in which NatureServe cloaks its Explorer website, it remains just a website, run by a political advocacy group.  And (how many times must we warn our students?) the internet is a wild and woolly marketplace of information, both the good and the bad, and the buyer must beware.  Each report returned by the NatureServe Explorer comes with the following disclaimer: “All documents provided by this server are provided “as is” without warranty as to the currentness, completeness, or accuracy of any specific data.”  In the final analysis, the Explorer database is not peer-reviewed science, and it does not pretend to be.

Thank heaven no legitimate researcher would ever confuse spurious data made available from the website of an advocacy group with reliable science.  Thank heaven.


[1] Yes, it does seem plausible to me that the initial state-by-state freshwater gastropod distributions uploaded to the NatureServe Explorer may have been the work of some intern hired to extrapolate the broad ranges found in J. B. Burch’s North American Freshwater Snails.  Burch lists 15 subspecies of P. gyrina, the ranges of at least two of which certainly include Delaware.  The range of Physella gyrina aurea is given as “New Jersey to Kansas, south to Arkansas and Florida,” and that of Physella gyrina cylindrica is given as “Ontario and New York south to Virginia.”  Then did our young intern simply miss Delaware when extrapolating “New England to Ohio, Tennessee and the Virginias” for P. heterostropha?  And did that intern miss Delaware when extrapolating “Eastern United States, from Maine west to Iowa, south to Texas and Florida” for Menetus (Micromenetus) dilatatus?  And so forth?  The entire enterprise is a house of cards.

[2] Brown, D. S. (1994)  Freshwater Snails of Africa and their Medical Importance (Second Edition).  Taylor & Francis, London.  608 pp.

[3] My main problem with NatureServe is the pseudoscientific method by which they gin up “conservation status ranks.”  See:
  • Toward the Scientific Ranking of Conservation Status [12Dec11]

1 comment:

  1. Posted on behalf of Jay Cordeiro:

    Hello Rob.

    I believe we have discussed this issue before in person and online on your blog (see http://fwgna.blogspot.com/2011/12/toward-scientific-ranking-of.html). No need to go into details there again. Please review the discussion, however.

    Anyway, whether what you say is true or not (and some of it is- see I can be reasonable) is irrelevant to the role Natural heritage ranking plays in mollusk conservation. The NatureServe database is not intended to be scientific with a testable hypothesis using the scientific method. The database is to be used as a source for information useful for biological species, population, and ecosystem conservation. It is an assemblage of data on current taxonomy, fence, distribution, occupancy, habitat, threats, trends, rarity, and conservation for select groups of organisms in North America. Much like your Freshwater Gastropods of North America (albeit without identification keys), it consolidates lots of information into an easily accessible, user friendly location freely available to the public at large.

    Much like a field guide or natural history atlas, the information contained within is just that- information only. Arguably the NatureServe Explorer online database is the most valuable source of information on North American species conservation because it contains so much information on so many taxa. This includes information (even when incomplete as with ) on "common" or otherwise non-imperiled taxa. This is in contrast with other conservation status ranking methodologies like USESA and AFS.

    This system is naturally inherent with untested errors. The same could be said of any published guide book, museum specimen lot (especially so), and dare I say it, your own FWGNA web site! The beauty of this system however is that the information is available publicly and can be easily corrected. In the case you mentioned about Delaware occurrences, you would not even be aware of the absence of such records in Delaware had you not been utilizing the NatureServe Explorer database in the first place (and I'm guessing this not the first time you've used it). The error can be rectified increasing the accuracy of the database through peer review (the defense here might I request that the court hereby consider Mr. Dillon a hostile peer reviewer?). Such review and accompanying corrections are actually encouraged to make the database a more accurate resource.

    In short (I guess this was not so short), please reconsider your opinion of the NatureServe Explorer database as an information source rather than a scientific study... And please, continue to send in your corrections. They only make the database stronger.


    Jay Cordeiro
    Northeast Natural History & Supply