The AUI Farmland Database (GIS landcover database)
Figures from the rapport later.
The Agricultural University of Iceland has produced a GIS database with vegetation classification map with relatively good resolution, the so-called Nytjaland database (AUI Icelandic Farmland Database). It is aimed to reflect the productivity and land use properties (i.e. for grazing) of the Icelandic vegetation. The AUI Farmland Database land cover (Nytjaland) was created based on supervised classification of satellite images. The project was initiated around 2000 but was mostly halted around 2008 due to finance constraints. It uses 10 classes for vegetation in addition to glaciers/snow and open water. Following is a short description of each class, but tabular data for these classes are presented in Table 6.
Cultivated land and hayfields (1690 km2). This category includes all cultivated land including harvested hayfields. Revegetated areas which have been seeded and fertilized belongs to this class, but due to limited vegetation in these areas they are often classified (in the Remote Sensing process) into other classes, dominated by less vegetation.
Shrubs and forests (1823 km2. Data from Icelandic Forest Service). This category includes land dominated by willow (Salix phylicifolia, S. arctica and S. lanata) and mountain birch (Betula pubescens).Undergrowth consists most often of forbs, grasses and heath vegetation. All forestry also belongs to this category. In the edition, of the Nytjaland land cover map, which was prepared in connection with this paper, the classified Shrubs and forests were merged into Rich heathland class (see below). Forest data from the Icelandic Forest Service were added into the Nytjaland data set instead.
Grasslands (2418 km2). Grasslands occur were growing conditions are favorable, with ample soil moisture, commonly in depressions or in toe-slope positions and in the lowland plains. Forbs are often prominent.
Saturated wetlands (3948 km2). The AUI Farmland Database (Nytjaland) separates between saturated wetlands and damp wetlands (‘hálfdeigja’), the latter having aquic soils but partial drainage leads to a mixture of plants characteristic of wetlands and species more common within the dryland vegetation classes. The wetland species include Carex spp., such as Carex bigelowii, C. lyngbyei, C. rostrata, C. chordorrhizia, and Equisetum spp. Cotton grass (Eriophorum angustifolium) is quite common as is heathland vegetation discussed below.
Damp Wetlands (1787 km2) are wetland areas with partial drainage, often at the margin of the saturated wetlands. Species include Carex spp. such as Carex bigelowii, C. nigra, and C. vaginata, Equisetum spp. such as E. arvense and E. palustre, and also Juncus arcticus. Eriophorum angustifolium is very common. Other species include the grasses such as Agrostis capillaris, Deschampsia caespitosa, Festuca richardsonii, Luzula multiflora and heath vegetation. Willow species (Salix spp.) and dwarf-birch (Betual nana) are common in damp wetlands and sometimes birch (Betula pubescens). Ground water level is usually high.
Rich heathland (6439 km2). The Icelandic heathlands have also been termed ‘dwarf shrub heath’. They are separated into two classes: rich heathland and poor heathland in the AUI Farmland Database (Nytjaland). Rich heathland is dominated by dwarf heathland vegetation, such as dwarf-birch (Betula nana), blueberries (Vaccinium uliginosum, V. myrtillus), crowberries (Empetrum nigrum), common heather (Calluna vulgaris) and Arctostaphylos uva-ursi, but also willow species (Salix phylicifolia, S. arctica and S. lanata). Moss species are also common, such as Rachometrium spp. Rich heathland also has a significant component of herbaceous plants that are good for grazing, both grasses and forbs. This separates the rich heathland from the poor heathland below.
Poor heathland (24 450 km2). Poor heathland is by far the most extensive vegetated class, covering about ¼ of the country. This class is dominated by the heath species and has usually a large component of moss, such as Rachomitrium lanuginosum. Good grazing plants are not as abundant as in the rich heathland. 3
Moss (3293 km2). This vegetation class is dominated by moss species covering more than 50% of the surface. Common moss species include Rachomitrium lanuginosum, Rachomitrium ericoides, Hylocomium splendens and Rhytidiadelphus squarrosus. The land covered with moss has quite low production of green biomass and has limited value for grazing. One of the distinctive characteristics of Icelandic vegetation is the abundance of surfaces covered by moss. Mosses also appear in most other vegetation classes and it is a primary succession vegetation on recent lavas.
Poorly vegetated - half vegetated land (12 922 km2). A large proportion of Iceland is poorly vegetated. This class represent land with scattered vegetation cover (20-50%). It is often isolated hummocks of plants well adapted to these conditions such as Cerastium alpinum, Silene acaulis, Armeria maritime, Thymus praecox subsp. arcticus. Willow and heath is also common within the vegetation patches or hummocks. Poorly vegetated land occurs within desertified areas, but also at high elevations and areas disturbed by volcanic events and flooding. It occurs also within degraded areas with shallow soils, resulting in rock outcrops where part of the soils have been lost.
Barren land (30 337 km2) is characterized by scattered vegetation cover (0-20%) with the same plants as within the poorly vegetated class. The poorly vegetated and barren surfaces consist of a variety of geologic surfaces, such as sand surfaces, lag gravel, and lavas.
The classification used available multispectral satellite coverage, including Landsat 7 and SPOT 4 and 5. The report describes the classification methods in some detail, but an English version if this text will be published later. It also describes the main problems with this classification, including the high diversity within classes, boundary problems (between vegetation classes and on the ground).
Water information was obtained from the National Land Survey of Iceland, and forest information from the Icelandic Forest Service. Some information about agricultural land has been digitized into the database. The classification is based on 12 100 control points on the ground and it was verified by 6550 verification points. Accuracy (Error Matrix) was about 70%, but much of the mismatch was due to unclear differences between ecologically similar classes, making this level of accuracy acceptable for the purposes of the system. These similar classes include grasslands and agricultural land (hay-fields), poor heathland and half vegetated land, the heathland classes and so on.
Only 70% of Iceland was covered with this classification (termed Nytjaland N12), but the remaining part of the Iceland (mostly highlands) were classified into fewer categories (Nytjaland N6) and an upgraded version (N8) has subsequently been developed with 76% accuracy. The Nytjaland project shows that 45 691 km2 of Iceland is vegetated land with >50% cover, with poor heathland being the most abundant vegetation class.