27% of species have disappeared from Mass. pond author made famous
                                
                                
                                    (Newser) -
                                    While living at Walden Pond, Henry David Thoreau collected detailed data on the plant species native to Concord, Mass. Scientists studying climate change have compared those records to present-day biodiversity—and found chilling evidence of global warming’s effects, the Boston Globe reports. 27% of the species Thoreau documented are...