| INTRODUC TI ONIn a rapidly changing world with increasing pressure on natural resources, land-cover maps are of utmost importance for area planning and resource management (Fuchs, Herold, Verburg, Clevers, & Eberle, 2015). Land-cover maps depict the physical cover of the surface of the Earth. Vegetation, for example the plant species composition (Box & Fujiwara, 2005), is the physical cover most often used for land-cover mapping because plants are easy to observe and vegetation types can be identified using a wide variety of methods. The plant species composition reflects variation along important environmental complex gradients (Whittaker, 1967), thus vegetation-based land-cover maps can also be used as a proxy for the ecosystem, i.e. all species present at a site, the environmental conditions and the processes and mechanisms by which the environment influences the species (cf. Tansley, 1935). Lakes, rock outcrops and vast areas of constructed sites and land otherwise heavily modified by man do, however, lack natural vegetation and hence are Abstract Questions: Land-cover maps are used for nature management, but can they be trusted? This study addresses three questions: (1) what is the magnitude of between field worker inconsistencies in land-cover maps and what may cause such inconsistencies; (2) in which ways and to what extent do spatial scale and mapping system influence inconsistencies between maps; and (3) are some biomes mapped more consistently than others, and if so, why?Location: Gravfjellet, Øystre Slidre municipality, southern Norway.Methods: Two different mapping systems, designed for mapping at different spatial scales, were used for parallel mapping by three different field workers, giving a total of six maps for the study area. Spatial consistency of the resulting maps was compared at two hierarchical levels for both systems. Results:The average pair-wise spatial consistency at the highest hierarchical level was 83% for both systems, while the average pair-wise spatial consistency at the lowest hierarchical level was 60.3% for the coarse system and 43.8% for the detailed system. Inconsistencies between maps were partly caused by the use of different land-cover units and partly by spatial displacement. Conclusions:Field workers made different maps despite using the same mapping systems, materials and methods. The differences were larger at lower hierarchical levels in the mapping systems and increased strongly with system complexity.Consistency among field workers should be estimated as a standard quality indicator in all field-based mapping programmes. K E Y W O R D S delineation, ecosystem mapping, ecosystem types, GIS, map quality, precision, repeatability, vegetation mapping, vegetation types SUPPORTING INFORMATION Additional Supporting Information may be found online in the supporting information tab for this article. APPENDIX S1 Details of the aerial photos APPENDIX S2 Details of the NiN system, and the update from the preliminary system to the revised system APPENDIX S3 Method for and res...

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During recent decades, forests have expanded into new areas throughout the whole of Norway. The processes explained as causing the forest expansion have focused mainly on climate or land use changes. To enable a spatially explicit separation of the effects following these two main drivers behind forest expansion, the authors set out to model the potential for natural forest regeneration following land use abandonment, given the present climatic conditions. The present forest distribution, a number of high-resolution land cover maps, and GIS methods were used to model the potential for natural forest regeneration. Furthermore, the results were tested with independent local models, explanatory variables and predictive modelling. The modelling results show that land use abandonment, in a long-term perspective, has the climatic and edaphic potential to cause natural forest regeneration of 48,800 km 2 , or 15.9% of mainland Norway. The future natural forest regeneration following land use change or abandonment can now be spatially separated from the effects of climate changes. The different independent model tests support the main findings, but small fractions of the modelled potential natural forest regeneration will probably be caused by other processes than land use abandonment.

Long-term and varied land use has had a major influence on the vegetation in rural Norway, and the traditional open landscapes are now being replaced by forests. In the present investigation, we assess and quantify structural vegetation changes caused by changes in land use and climate. Up-to-date actual vegetation maps from three rural study areas were compared with interpreted historical vegetation maps and potential natural vegetation (PNV) models. Our findings indicate that the present vegetation structure is strongly influenced by land use. In the studied sites, 56-66% of the areas presently have another vegetation type than expected from a natural state (PNV). The mean turnover of vegetation types in the study areas during the past 35-40 years was 25%. Our study highlights that the influence of land-use needs to be accounted for when considering the effects of climate change.