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The study focuses on vegetation changes in the Nordic mountain birch forest in northern Norway, covering a period of more than 40 yr. The study area comprises the municipalities of Kautokeino and Karasjok on Finnmarkskvidda; it is predominantly covered by lichen and dwarf shrub vegetation. Sizes of various vegetation classes were estimated by the use of remote-sensing techniques and ground surveys. A significant change in vegetation cover during the study period was registered in the whole study area. Vegetation types dominated by bilberry (Vaccinium myrtillus), wavy hair-grass (Deschampsia fleuxuosa), the dwarf cornel (Cornus suecica), and mosses have tripled in abundance compared to 40 yr ago. In contrast, lichen-dominated heaths and woodland (forests), preferred by the reindeer stocks intensively utilizing these areas of Finnmarksvidda, have decreased by approximately 80% in abundance during the same period. Correspondingly, there has been a significant increase in the extent of birch forests especially in Kautokeino (90% increase). The reason for the steep decline in lichen-dominated areas appears to be a direct consequence of the intensive grazing by the increasing reindeer population in the period 1961-1987, but climate change (increased precipitation), caterpillar attacks, and long-transported air pollution (e.g., nitrogen) may also have accentuated the increase of forests and other vegetation types.

BackgroundGlobal environmental change is causing spatial and temporal shifts in the distribution of species and the associated diseases of humans, domesticated animals and wildlife. In the on-going debate on the influence of climate change on vectors and vector-borne diseases, there is a lack of a comprehensive interdisciplinary multi-factorial approach utilizing high quality spatial and temporal data.MethodsWe explored biotic and abiotic factors associated with the latitudinal and altitudinal shifts in the distribution of Ixodes ricinus observed during the last three decades in Norway using antibodies against Anaplasma phagocytophilum in sheep as indicators for tick presence. Samples obtained from 2963 sheep from 90 farms in 3 ecologically different districts during 1978 – 2008 were analysed. We modelled the presence of antibodies against A. phagocytophilum to climatic-, environmental and demographic variables, and abundance of wild cervids and domestic animals, using mixed effect logistic regressions.ResultsSignificant predictors were large diurnal fluctuations in ground surface temperature, spring precipitation, duration of snow cover, abundance of red deer and farm animals and bush encroachment/ecotones. The length of the growth season, mean temperature and the abundance of roe deer were not significant in the model.ConclusionsOur results highlight the need to consider climatic variables year-round to disentangle important seasonal variation, climatic threshold changes, climate variability and to consider the broader environmental change, including abiotic and biotic factors. The results offer novel insight in how tick and tick-borne disease distribution might be modified by future climate and environmental change.

The overall objective of this paper is to present and discuss the most recently developed vegetation map for Svalbard, Arctic Norway. The map is based on satellite images in which several Landsat TM/ETM+ images were processed through six operational stages involving: (1) automatic image classification, (2) spectral similarity analysis, (3) generation of classified image mosaics, (4) ancillary data analysis, (5) contextual correction, and (6) standardisation of the final map products. The developed map is differentiated into 18 map units interpreted from 37 spectral classes. Among the 18 units separated, six of the units comprise rivers, lakes and inland waters, glaciers, as well as non- to sparsely vegetated areas. The map unit 7 is a result of shadow effects and different types of distortions in the satellite image. The vegetation of the remaining eleven units varies from dense marshes and moss tundra communities to sparsely vegetated polar deserts and moist gravel snowbeds. The accuracy of the map is evaluated in areas were access to traditional maps have been available. The vegetation density and fertility is reflected in computed NDVI values. The map product is in digital format, which gives the opportunity to produce maps in different scales. A map sheet portraying the entire archipelago is one of the main products from this study, produced at a scale of 1:500,000.

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