Dr. Rob Dillon, Coordinator

Wednesday, November 8, 2023

Atlantic Drainages Update

Our hunger to advance the cause of freshwater gastropod science is insatiable here at the general headquarters of the FWGNA Project.  I’m always scanning the literature for the latest research and looking to add new records to the database, even for those regions we covered and published many years ago, from which we seem to have long moved on.  We haven’t “moved on” from anywhere.  Our coverage extends over all or part of 17 states, expanding south and west, active to the present day.

But it has been ten years – if you can believe it – since we last updated the five web resources that cover the freshwater gastropod fauna of U.S. Atlantic drainages:  Georgia (FWGGA), South Carolina (FWGSC), North Carolina (FWGNC), Virginia (FWGVA) and the Mid-Atlantic (FWGMA).

Fresh 2023 Format
So a couple months ago we were able to twist the arm of our good friend Martin Kohl to help us with a fresh set of maps, which is the biggest piece of the chore.  And today we are pleased to announce that the results of Martin’s considerable GIS skills are now available for download from the pages of the 72 species and subspecies of gastropods inhabiting rivers, lakes, ponds and streams of the vast (ten-state) Atlantic-drainage area.

The maps newly available for 2023 are built on a database of 12,138 records.  That number represents a 4.2% reduction from the 12,674 Atlantic-drainage records upon which we based our (most recent) Synthesis v3.1 and Biogeography v2.0 back on 12May22.  The new total reflects a pruning of our FWGNC database from 4,425 down to 3,809 records to remove a big batch of near-duplicate samples, collected by NCWRC teams upstream and downstream from bridges, for example.

Other FWGNA Atlantic-drainage databases have been slightly augmented by routine collecting, however, up from 895 to 960 in Georgia, from 1,938 to 1,989 in South Carolina, from 2,333 to 2,396 in Virginia, and from 3,150 to 3,159 in the Mid-Atlantic states.  Note that the sum of those five figures totals slightly more than 12,138 due to double counting where rivers comprise state lines.

Our 2013 maps emphasized rivers, streams, and vegetative cover.  Our new 2023 maps have been significantly reformatted to show the major USGS/EPA Ecoregions, with counties and cities (very lightly) in the background.  Close comparison of the two examples (above and below) will reveal a slight reduction in data density for North Carolina, and some fresh data mapped, especially in Georgia.

Old 2013 Format

The contents of all 128 species pages on the FWGNA site have also been refreshed in recent months – not just the 72 species and subspecies of Atlantic drainages.  I am always on the lookout for new research to add to the bibliographies – ecology, life history, systematics, evolution – anything and everything, really.

Whenever any of you publish anything new, please send me a link or a reprint.  Indeed, if you happen to read a new paper with especially interesting or important results on any aspect of the biology of North American freshwater gastropods, written by anybody else, I always appreciate a heads-up.

For many years, my customary sign-off has been, “Keep in touch.”  I mean it, I’m serious!