sentences:  In the lower reaches, the landscape changes slightly to grassland and upland heath with underlying boulder clay, alluvium and peat.The Rede is known for its salmon, trout and otter, which are commonly seen within its waters.The river is notable for being one of the few places in England to have a freshwater pearl mussel population, which in 2006, was estimated at 50,000 mussels across the Rede and the North Tyne.