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Book details
  • Genre:SCIENCE
  • SubGenre:Life Sciences / Zoology / Invertebrates
  • Language:English
  • Series title:The Freshwater Gastropods of North America
  • Series Number:4
  • Pages:268
  • Paperback ISBN:9780960084333

Essays On Ecology and Biogeography

by Robert T. Dillon, Jr.

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Freshwater snails are common and familiar inhabitants of rivers, lakes, and streams throughout North America. In some environments they comprise the majority of the macroinvertebrate biomass, significantly influencing community composition, energy flow, and nutrient cycling. Yet their biology remains almost as obscure to the scientific community as to the lay public. Collected here in Volume 4 of the FWGNA series are 38 essays on the ecology and biogeography of North American freshwater gastropods, originally published in blog form 2003 - 2017, edited and rearranged thematically. Patterns of distribution are reviewed and analyzed at regional scales, with particular emphasis on mechanisms of dispersal. New invasions are reported, their progress monitored, and their consequences examined. The subjects of rarity and endemism, first introduced in Volume 3, are explored at greater depth in Volume 4 as well.

The scholarly study of biogeography has, in recent years, become entangled with public policies regarding endangered species conservation and invasive species control. Here we review several striking cases where natural resource agencies have been misled by conservation biologists biased by research funding. We suggest that the correct relationship between science and public policy is analogous to playing baseball and playing the banjo – neither compatible nor incompatible, neither better nor worse, just entirely different.


The Freshwater Gastropods of North America Project is a long-term, collaborative effort to survey the entire gastropod fauna inhabiting every river, lake, pond and stream in the continental United States and Canada.  Born in the summer of 1998 at the World Congress of Malacology in Washington, the effort has covered all or part of 17 eastern states to date, extending from New York to Mississippi.  Volume 1 in this series analyzed the results of a scientific survey of the freshwater gastropod fauna of the Atlantic drainages from Georgia through Pennsylvania, Volume 2 added important supplementary information on the evolutionary biology of the pulmonate snails found in that vast region, and Volume 3 similarly for the prosobranchs.

The essays collected here in Volume 4 are offered as supplementary information on the population and community ecology of the freshwater gastropods, considering the entire fauna together.  They provide essential insight into the historical background, context, and rationale for the many methodological and taxonomic approaches advanced in Volume 1, and in Volume 5, covering the Ohio, Cumberland, and Tennessee drainages, published in 2023.

About the author

Dr. Robert T. Dillon, Jr. is America's foremost authority on freshwater gastropods. From 1983 until retirement in 2016 he was professor of biology at the College of Charleston in South Carolina. He is the author of The Ecology of Freshwater Molluscs (Cambridge University Press, 2000) and over 60 scientific papers on the genetics, evolution, and ecology of snails. A former president of the American Malacological Society, Dr. Dillon contributed the freshwater gastropod chapter to the popular 2006 AMS publication, The Mollusks: A Guide to their Study, Collection and Preservation. In 1998 he founded the Freshwater Gastropods of North America Project, authoring or coauthoring an extensive website, a popular blog, and seven hardcopy volumes to date.