Grief, beaver anguish makes me want to weep.
I do not condone the illegal release of beavers, but they really are not a serious problem. Go anywhere in Strathtay (below the Tummel confluence) or Strathisla around Coupar Angus where the beavers thrive and watch silt pour off fields ploughed tight to the margins (loaded with fertilizers, organic soils and a wide range of pesticides), over extraction of water to produce tatties that taste of nothing, river banks poached by grazing, diffuse pollution from livestock, manicured river margins for clients who cannot manage a roll cast, piss poorly designed levees, road drainage not subject to SUDS principals discharging directly (loaded with Sodium Chloride), burns loaded with decades of fallen lumber etc. etc.
The native trees they drop, aren't necessarily dead, it time the remain rootswill naturally rejuvenate ........ I think the old woodman called this pollarding.
Modern agricultural practice, remains the biggest threat to East Coast rivers, beavers are a wee blip by comparison