Persistence of alpine grass-dominated vegetation on abandoned mountain summer farms in Western Norway

Abstract

Centuries of seasonal farming in the Norwegian mountains led to a decrease in forested areas, a lowering of the alpine tree- and forest lines, and an increase in grassland coverage in the subalpine zone. Since the mid-19th century seasonal farming has declined significantly. In the sub-alpine belt, this has resulted in woodland succession on former hay meadows and open grasslands and heathlands. In contrast, vegetation changes caused by seasonal farming and its decline in alpine environments may be comparatively subtle because of unsuitable conditions for tree growth. The study examines vegetation changes in a former mountain summer farming area in the alpine zone of Western Norway using data on present and previous vegetation and old photographs. On curtilages high levels of defoliation, trampling and nutrient accumulation resulted in grass- and herb-dominated vegetation that differs significantly from that of surrounding areas. This curtilage-specific vegetation is persistent and occurs even at locations that have been grazed with only low intensity for several decades. Local concentrations of nutrients are probably a key factor that maintains the grass-dominated vegetation and strongly delays or even prevents regrowth of shrub heath.

Keywords:

• livestock grazing
• multivariate analysis
• nutrients
• rephotographing

Acknowledgements

I thank Mary Edwards, Sebastian Eiter, Marc Antrop, Martin Price, and the anonymous reviewers for their valuable comments on this paper. Rune Halvorsen Økland advised on some statistical procedures. Also, the County Archive of Sogn og Fjordane is thanked for permission to reproduce photographs. The research was supported financially by the Research Council of Norway (Norges forskningsråd).

Notes

1. This paper is based on a previous version which is part of a doctoral thesis (Potthoff 2005).

2. Seasonal farm (seter/st⊘l) is used as general term covering a property in the outfields used annually in one or two particular periods. Mountain summer farming specifically refers to activities in the mountains and during summer. The term ‘mountain summer farmstead’ (st⊘lstun/setertun) is used when referring to the plot of land where the buildings are located including the buildings.

3. Arbeitsgruppe für Bodenkunde, Landschaftsökologie und angewandte Botanik GmbH.