In the Scandinavian mountains, grazing animals are transported from permanent settlements in the valleys to utilise the rich pastures in the mountains during summer. This practice, essentially an altitudinal transhumance system, is known as 'summer farming' in Scandinavia, but is also known from mountainous regions elsewhere in Europe and Asia.

During centuries of continuous low-intensity land-use, the perennial grasslands at summer farms have become characteristic and stable vegetation types that are often very rich in species. Different floristic elements meet here; generalist grassland herbs and grasses, more demanding semi-natural grassland specialists, alpine plants that take advantage of the open vegetation structure created by the grazing animals, and common subalpine plants.

At the landscape scale, these grasslands at summer farms appear as 'habitat islands' that are scattered throughout extensive sub- and low-alpine heaths and woodlands. Due to changes in agricultural technology and economy in the past 50 years, the land-use is now decreasing and the vegetation and flora of these cultural landscapes are changing.

Summer farms in use.
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In the mountains of Norway, the total biomass harvested by grazing and mowing has decreased by 61% from 1939 to 1996 (Edelmann 1997).

The aim was to gain insight into the processes governing the vegetation dynamics of mountain summer farms at several scales ranging from the landscape scale via vegetation types to local populations, and to study effects of changes in the land-use regime on diversity, composition, functional and morphological traits and regeneration. The results can be used to make predictions about the future development of the vegetation and flora of the summer farm landscape.

1. Studies of species composition, diversity, and plant functional trait responses at summer farms with different land-use history (i.e. toposequences) showed that local land-use effects create strong floristic patterns and are of overriding importance for the vegetation composition and structure. Landcsape-scale processes also contribute significantly, however.

2. Revegetation dynamics of bare-ground gaps within the grassland sward had strong effects on the local floristic composition that remained for more than three years after gaps were created. Differences between species in bare-ground colonising ability could partially explain gap effects. The lower overall disturbance regime at abandoned summer farms affected gap revegetation dynamics, and also the long-term local population persistence of gap-dependent species.