Chat Moss along with Risley Moss and Holcroft Moss, is also a European Union designated Special Area of Conservation, known as Manchester Mosses. The major habitats in the moss are bog, heathland, woodland and acidic grassland, subject to varying degrees of wetness depending on the local drainage. The remaining areas of bog are dominated by common cottongrass "Eriophorum angustifolium" and hare's-tail cottongrass "E. vaginatum". Bog mosses are more scarce, but "Sphagnum cuspidatum", "S. recurvum", "S. tenellum", "S. fimbriatum" and "S. subnitens" occur in patches. As the peat has become drier, areas have been taken over by purple moor grass "Molinia caerulea" and
Portlethen Moss have been enhanced by proximity to the sea and natural defensive protection of the moss to impede intruders. From Tacitus accounts of the Roman general Agricola, it is known that the Romans were daunted by Portlethen Moss, Netherley Red Moss, Cookney Moss and other local bogs that hindered travel. This is also evidenced by the Roman Camp of Raedykes having been established immediately south of this cluster of mosses; the Romans not being able to progress further north, turned inland toward Netherley.The Portlethen Moss is near the Grampian Mountains. The ancient Causey Mounth passage specifically connected the Bridge of Dee