>Incidentally, would you like to tell the assembled Conchlers about the recent FMCS Gastropod Workshop here in Tuscaloosa? Granted, freshwater gastropods are not everyone's forte, but we promise to sit quietly and learn.<

A fair amount of information is becoming available on the FMCS and FWGNA websites.  The workshop had two parts, with the first two days addressing general water quality issues (including the well-being of major groups of organisms) and the last two days surveying freshwater gastropods.  Over 100 people attended at least part of the meeting.

Like the mussels, about 70% of the freshwater gastropods in the US and Canada are considered imperiled, making the freshwater mollusks perhaps the most imperiled major group of organisms.  Major threats include pollution, siltation, demand for water for other uses, and modification of stream flow (e.g., dams, channelizing).  Introduced species may also pose a threat.  Alabama is the capital of diversity and imperilment, where dams on the Coosa river eliminated one subfamily, four genera, and dozens of species.

We have several families of freshwater snails here.  Important distinguishing features include the shell shape, size (from subatomic hydrobiids to ampulariids that can feed a family of four, according to Tom Watters), color and sculpture patterns, operculum form, and several anatomical characters.  The Hydrobiidae are the most diverse, though many current workers are splitting this family into multiple families.  Hydrobiids and pleurocerids are the most imperiled; the hydrobiids including many species that occur at only a few localities and the pleurocerids including several species specialized for undisturbed large river habitats.

If suitable habitat is available, reintroduction of rare species into places where they once lived can be fairly successful.

Any particular details of interest?

    Dr. David Campbell
    Old Seashells
    University of Alabama
    Biodiversity & Systematics
    Dept. Biological Sciences
    Box 870345
    Tuscaloosa, AL  35487-0345 USA
    [log in to unmask]

That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa

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