|
Résumé :
|
During a 1956 survey of 233 sampling stations located approximately every five miles on the Cheat River and all its tributaries. Only five species of mollusks were found to inhabit this watershed which lies in West Virginia and Pennsylvania and its tributary to the Monongahela River. Four families of gastropods, each represented by one species, and one pelecypod species occupy this system. Pollution and the resulting water pH throughout the system between Parsons, West Virginia, and the West Virginia-Pennsylvania state line were the major limiting factors considered to restrict the known species to the headwater areas south of Parsons, West Virginia. It is surprising that mollusks were absent in the one possible retreat area, the headwaters of Big Sandy River north of Bruceton Mills, West Virginia. Natural barriers of waterfalls, gorges, underground streams and environment all played important roles in determining the distribution of mollusks within the Cheat River watershed. However, the constant and rapidly expanding destructive acid mine pollution exerted a much greater influence than did these natural features upon the distribution of the mollusks within the system.
|
