John Connolly, Nicholas Holden
Proceedings of the 14th International Peat Congress
Theme I. Inventory, stratigraphy and conservation of mires and peatlands
In this research we mapped the extent of disturbance on Irish peatlands using an object oriented approach and medium and high-resolution imagery. Peatlands in Ireland contain between 53-62% of SOC on 20% of the Ireland’s land area. These peatlands have been extensively disturbed by drainage and converted to agriculture, forestry and industrial or domestic extraction. Previous studies concluded that over 85% are disturbed. The medium resolution imagery (IRS) data dates from; 2005 to 2007 and most of the high resolution data (Ikonos/Geoeye) are more recent; from 2009 to 2010. The peatland extent was delineated using the Derived Irish Peat Map version 2 (DIPM2). A disturbance cube was used to determine the severity of disturbance. The object oriented approach uses the Feature Analyst extension in ArcGIS. Feature Analyst is a black box system.
Some difficulties were recorded in cutover areas where there is a spatially complex and heterogeneous mosaic of vegetation communities. However the overall accuracy assessment was good for the medium resolution imagery ranging from 72 to 73%. However, the use of high resolution imagery increased the overall accuracy of the disturbance maps to between 85 and 90%.