Location and Topography
Rochdale metropolitan borough lies in the extreme north east of Greater Manchester and is primarily an upland district. The moorland in the north and east is between 200 and 400 metres above sea level (asl), reaching its high point of 472 m asl near the dramatic millstone grit escarpment of Blackstone Edge.
A significant part of the South Pennine Moors Special Protection Area (SPA) lies within Rochdale. The borough contains over 80% of the county's blanket bog (a UK BAP priority habitat). It also supports over 90% of the wet modified bog and more than half of the acidic flush habitat. The moorland also contains significant areas of bracken, the highest proportion of any GM district.
The high rainfall associated with the western Pennine edge is channelled into numerous reservoirs, some of which are at high altitude.
In the west of the borough there are important areas of semi-natural broadleaved woodland, such as Ashworth Valley, occupying the cloughs running down off the uplands.
The River Roch has its source high up on the moors and flows south-west through the borough, providing an important wildlife corridor through the urban areas.
Certain stretches of the Rochdale Canal have been designated as a Site of Special Scientific Interest (SSSI) and a Special Area for Conservation (SAC). A high proportion of Greater Manchester's grassland is found in Rochdale, with more than a third of the county's unimproved acid grassland and nearly 60% of the marsh/marshy grassland.
The South Pennine Moors SPA supports nationally important upland breeding bird populations including Curlew, Dunlin, Golden Plover, Red Grouse and Twite. There are extensive areas of heather. Sphagnum and other bog forming mosses occur locally, with the characteristic cotton-grasses which flower in June and July, adding splashes of white to the upland landscape.
Water Voles still maintain a healthy population along some of the brooks.
Roe Deer have increased significantly in numbers over recent years, taking advantage of the new areas of woodland planting.
The number of species of Damselfly and Dragonfly has increased as their ranges expand north, including the elegant Banded Demoiselle which frequents the Roch. A good selection of butterflies can be found, including the Wall Brown which maintains a stronghold on the moorland fringe.
The Rochdale Canal supports the European Protected Species floating water plantain (Luronium natans), as well as American Pond Weed and White-clawed Crayfish.