Beavers are well-known residents of rivers, lakes and streams across North America.  New research finds they are also far more common in estuaries and tidal wetlands than was previously understood. The study suggests the rodents are critical ecosystem engineers in a habitat where twice-daily tides raise and lower water levels, bringing saltwater inland from the sea. Estuarine ecologist and self-described “accidental beaver biologist” Greg Hood surveyed estuaries and tidal wetlands across coastal British Columbia and the U.S. states of Washington and Oregon. He found beavers (Castor canadensis) in those ecosystems by surveying places other scientists tend to overlook. “Estuarine scientists and beaver biologists are generally working in other areas — the beaver biologist in normal streams and lakes where they expect to find beavers; the estuarine ecologists typically in herbaceous tidal marshes or even in eelgrass,” Hood told Mongabay in an email. Adding that scientists rarely work in “tidal shrub and forest habitats (tidal swamps) where beaver are most likely, because tidal swamps are very hard to move around in.” Hood found that beavers are widespread in tidal habitats across the Pacific Northwest. In some tidal channels of the Snohomish and Skagit rivers, he found beaver dams at twice the density of such dams on non-tidal rivers. Beaver dams in tidal habitats are shorter than those on non-tidal rivers, according to Hood’s research. He hypothesizes that since these dams are flooded at high tide, that their main function is to trap water at low tides, which allows beavers to continue…This article was originally published on Mongabay

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