Changes in forest soils and vegetation in Søgne, southern Norway, during a 20 year period

Abstract

An investigation of the edaphic conditions and the vegetation of 21 fixed plots in Søgne municipality, Vest‐Agder, South Norway was carried out in 1967‐69 and 1987. Loss on ignition, pH, total nitrogen, total exchangeable bases, base saturation, exchangeable hydrogen, sodium, potassium, magnesium, calcium and manganese was analysed. The species composition of vascular plants was investigated. The total cover of the bottom layer was scored. The soil pH had decreased in the more basic soils but had increased in the more acidic soils. The organic content had increased and base saturation had decreased in most samples. Na+ had increased in more than half of the plots, Ca2+ and Mg2+ had not changed, and K+ and Mn2+ had decreased in most plots. Salt depositions from the neighbouring North Sea and leaching from the soil accounted for these changes. In many of the parameters opposite changes were found in the poorer soils compared to the richer soils. In the field layer Deschampsia flexuosa, Convallaria majalis had increased, and Oxalis acetocella, Galium odoratum had decreased. The cover of cryptogams had decreased in most of the plots.

Two decades of change in the ground vegetation of a mixed deciduous forest in an agricultural landscape

“…The methodology and its consequences for the validity of the results may be discussed since semi-permanent plots (sensu Persson 1980) were used and different researchers participated in the data collection. However, these methodological inconveniences frequently occur in long-term vegetation studies (Malmer et al 1978;Brewer 1980;Persson 1980;Wilmanns et al 1986;Persson et al 1987;Falkengren-Grerup 1990;Björnstad 1991;Diekmann & Dupré 1997;Brunet et al 1998;Diekmann et al 1999), but the results are seldom questioned. Variation in plot positions was always less than a few metres, due to detailed information on the plot positions in 1977-1980. Despite the methodological inconveniences, this research clearly revealed that changes did occur in the herb and shrub layer of the Vorte Bossen over the 20 years of this study.…”

“…the Park Grass experiment) are a valuable means to test the applicability of ecological theory as a framework for predictions, but they are often complicated because of a lack of accurate historical vegetation data and a number of other practical problems, such as difficulties in relocating the original plots and participation of different researchers (e.g. Malmer et al 1978;Brewer 1980;Persson 1980;Wilmanns et al 1986;Persson et al 1987;Falkengren-Grerup 1990;Björnstad 1991;Diekmann & Dupré 1997;Nygaard & Ødegaard 1999).…”

Dynamics of understory vegetation in an old‐growth boreal coniferous forest, 1988–1993

“…Changes in species abundance have been shown for forests in C Europe (e.g. Wittig & Neite 1985) and S Sweden (Falkengren-Grerup 1986;Falkengren-Grerup & Eriksson 1990), but there is no evidence for such changes in Finnish and S Norwegian forests (Lähde & Nieppola 1987;Bjørnstad 1991).…”

Large‐scale changes in abundance of terricolous bryophytes and macrolichens in Finland

“…Air pollutants have been suggested to be of major importance in S Sweden, where a decline in bryophytes was detected (Hallingbäck 1992). In S Scandinavia, changes detected in soil pH and nutrient availability indicate that increased availability of nitrogen has influenced understorey vegetation more than acidification (Falkengren-Grerup & Eriksson 1990;Bjørnstad 1991). Without repeated large scale vegetation surveys based on statistically representative sampling the magnitude of these changes cannot be evaluated.…”