Future forest distribution on Finnmarksvidda, North Norway

Finnmarksvidda is Norway's largest mountain plateau, located in the Arctic/alpineboreal transition area. The area is also a central winter grazing area for the reindeer herds of the indigenous Sámi people. This study develops a bioclimatic-based model to simulate future potential vegetation, with a focus on forest types. The model utilizes a bioclimatic study in the region, where vegetation types have been grouped according to minimum summer temperature demands. This is then used as a base for modelling of future vegetation. Due to the flat landscape of Finnmarksvidda, the model shows that a 1°C increase in summer temperatures will potentially lead to an increase of forested areas by 4485 km², which is a 70% increase from the current 6900 km² to a simulated 11 706 km². This in turn will lead to a reduction of Arctic-alpine heaths from 4440 km² today to potentially only 670 km². Such changes will have consequences for the reindeer grazing system, as the predicted changes will lead to a decrease in the vegetation types that have high winter grazing accessibility for reindeer, from 2386 km² today to potentially only 377 km². On the other hand, vegetation types with medium accessibility will experience an increase, from 2857 to 3366 km².