Historian and author, John T. Crumbler, will tell us how, through the centuries, people affected Cape Cod's ecosystem.  Mr. Crumbler, the author of several books, is a professor at the University of Louisville in Kentucky, now teaching part time.  He has a cottage in Wellfleet and lives on the Cape during much of the year.  As a result, he has become concerned with the Cape's fragile ecosystems.