Mapping peatland disturbance in Ireland: an object oriented approach

摘要

Peatlands contain large amounts of soil organic carbon. In a pristine state they sequester atmospheric carbon dioxide (CO_(2)), however, when they are disturbed they emit it. In Ireland peatlands are extensive and cover 20percent of the national land area. They contain between 53percent and 62percent of the total national soil organic carbon. However, large areas of Irish peatlands have been disturbed by anthropogenic activity. This activity includes drainage, mechanical extraction and burning. These activities lead to the reduction of the resilience of the peatland to climate and environmental change and can lead to the increased vulnerability of the peatland carbon stock. In this research an object oriented approach is used to examine high resolution imagery of a raised bog in Ireland and to extract a map of disturbed peatlands. The object oriented approach is implemented in ArcGIS with high resolution Geoeye-1 satellite imagery. The main disturbance classes identified were rough grazing, pasture, molinia, coniferous forest, high bog, drained bog and scrub. The users accuracy for each individual class ranged from 66percent to 92percent and the overall accuracy assessment for the disturbance map 85percent.