Almost wiped out centuries ago by fur trappers, beavers have made a comeback in North America, including the Mid-Atlantic and the Chesapeake Region. While many see them as a nuisance -- slayers of trees, builders of dams that flood roads and farm land -- biologists and natural resource managers see good in the beaver comeback. Their dams create rich habitat for other mammals and fish while filtering sediment and damaging nutrients from waters that flow to the Chesapeake Bay.On the show:- Frances Backhouse, a Canadian writer and author of, ----Once They Were Hats: In Search of the Mighty Beaver.----- Mike Callahan, founder of the Beaver Institute who has resolved more than 1400 conflicts between beavers and humans.- Scott McGill, founder and CEO of Ecotone, a Maryland-based ecological restoration company that is bullish on the beaver as a benefit to the environment. (Photo courtesy of NPS / Neal Herbert) Links:http://www.baltimoresun.com/news/maryland/harford/aberdeen-havre-de-grace/ph-ag-beaver-dam-0406-20160407-story.htmlhttps://www.bayjournal.com/article/leaving_it_to_beavers_communities_make_room_for_natural_engineershttps://potomac.org/blog/2016/1/19/beaver-dam-nitrogen-waterhttp://www.backhouse.ca/books/https://www.beaverinstitute.org/https://www.ecotoneinc.com/