Complex sentence: Dumsey Meadow is a Site of Special Scientific Interest in Surrey, England; the only piece of undeveloped water meadow unfenced by the river remaining on the River Thames below Caversham, (Oxfordshire now Berkshire) and is home to a variety of rare plants and insects.
Split into simpler sentences: Dumsey Meadow is a Site of Special Scientific Interest in Surrey, England. It is the only piece of undeveloped water meadow remaining on the River Thames and is home to a variety of rare plants and insects.