We are excited to announce that a fresh set of pdf maps
detailing the ranges of all the freshwater gastropod species inhabiting
Atlantic drainages from Georgia to the New York line are now available for
download from the FWGNA site. This is
the first significant update of FWGNA mapping coverage since ever.
As our legions of loyal users will fondly recall, the oldest
sections of the FWGNA website featured downloadable pdf dot maps showing the
detailed distributions of freshwater gastropods in South Carolina (2005), North
Carolina (2005), Georgia (2006) and East Tennessee (2011). But neither our Virginia site (2011) nor our
Mid-Atlantic site (2013) ever featured pdf dot maps. And our maps of Georgia and Carolina
distributions have gone obsolete in the interim.
So the fresh set of range maps now available for download integrates
seamlessly with the version of the FWGNA site we rolled out in October of 2013,
based on 11,471 records of 68 freshwater gastropod species and subspecies inhabiting
the Atlantic drainages of nine states [1].
These 68 taxa have been divided into 26 sets of two or three related
species each (in most cases), and mapped in sets as a tool for the exploration
of potentially interesting joint distribution patterns.
As an example, click on the thumbnail above to download a
pdf map comparing the distributions of Pleurocera proxima, P. virginica, and P.semicarinata. You will see very little
overlap between these three widespread pleurocerids, proxima ranging throughout
small softwater streams of the Blue Ridge and upper Piedmont from Georgia to
Virginia, semicarinata inhabiting small hardwater streams in the Great Valley
of Virginia, and virginica in the streams and rivers of the lower North
Carolina Piedmont, spreading northward.
By way of contrast, click on the thumbnail below left to
compare the ranges of the hydrobiids Littoridinops tenuipes, Notogillia sathon,
and Spilochlamys turgida. While
populations of Littoridinops demonstrate specialization on a unique (freshwater
tidal) habitat up the entire length of the Atlantic Coastal Plain, Notogillia
and Spilochamys are positively associated, very strikingly tending to occur
together in a narrow patch of central Georgia.
A complete set of updated maps every bit as interesting as
these are available today from the FWGNA site for the entire freshwater
gastropod fauna of US Atlantic drainages.
Visit any of the 68 separate species and subspecies covered, scroll down
to the “Supplementary Resources” heading, click on the “Atlantic drainages”
link, and enjoy!
We are pleased to acknowledge a great debt of gratitude to
Mr. Matt Ramsey, an undergraduate archaeology student here at the College of
Charleston with a bright future ahead of him. Great job, Matt!
Notes
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