Chat Moss, a lowland raised bog, formed after the last ice age about 10,000 years ago on the site of a shallow glacial lake to the north of the River Mersey. Fen peat formed in an area colonised by reeds and rushes. Sphagnum mosses then colonised the area causing a change from fen to bog peat which became elevated forming a dome, the raised bog. Sphagnum mosses increase the acidity of the water resulting in highly specialised plant species, many of them found nowhere else.[4] The site is also important for bird species such as the merlin, hen harrier and short-eared owl.[5]
