Essays On Ecology and Biogeography

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 in this volume are 38 essays on the ecology and biogeography of North American freshwater gastropods. 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 III, are explored at greater depth in Volume IV 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.

Volume I in this series analyzed the results of a scientific survey of the freshwater gastropod fauna of the Atlantic drainages from Georgia to the New York line. The essays collected here in Volume IV, together with those in Volume II (Pulmonates) and Volume III (Prosobranchs), will be essential companions to Volume I, as well as to additional volumes on the gastropod faunas of interior drainages forthcoming.

Volume I in this series reported the scientific results from our survey of the freshwater gastropods of United States Atlantic drainages, Georgia to the New York line.  In the preface to that volume, I mentioned that during the 20 years over which the FWGNA Project has unfolded, I developed the habit of sending regular emails to an expanding list of collaborators, a practice which ultimately evolved into an internet blog.  Those emails and blog posts have sometimes contained important supplementary information on the biology of the fascinating organisms toward which the FWGNA Project has been directed, as well as historical background, context, and rationale for various methodological and taxonomic decisions made in Volume I.

Volume II collected 29 essays on the pulmonate snails, and Volume III comprised 37 essays on the prosobranchs.  Both of those volumes were focused primarily on the evolutionary biology and systematics of the snails themselves.  Here we have assembled 38 essays focused on ecological themes, as the snails interact with their environments, and blundering humanity interacts with them.  These essays have been edited rather heavily from the form in which they were originally posted, in many cases, and re-ordered topically.  Essays 1 – 19 touch a variety of subjects on the broad themes of dispersal and biological invasion, as we find that we have too many snails, where they are not wanted, and Essays 20 – 29 focus on the rarity of freshwater gastropods, and their perceived endangerment, as we find that we have too few.  Essays 31 – 38 review more generally biogeographical topics, as we survey the landscape, wringing our hands about both situations, simultaneously.