Abstract, Astrid Brekke Skrindo

Instituttt for plante- og miljøvitenskap

Natural revegetation from indigenous soil

The main objective of this thesis was to increase the understanding about the early phase of natural revegetation from indigenous soil on severely disturbed areas.
To evaluate the outcome of revegetation from soils of different locations, investigations were conducted along a new main road (R23) in SE Norway. Prior to this study, the soil had been divided into topsoil (the upper 30 cm) and subsoil (the remaining soil), stockpiled separately, and redistributed with a 10 cm topsoil layer on the subsoil after the construction was finished.
Investigations included 10 different topsoil types at different locations, and experiments included one other topsoil and one subsoil type with and without fertilisation treatment and in different locations.
Revegetation was studied by recording changes in vegetation cover, vascular plant species richness and the abundance of each species in the first years of the revegetation period, and by analyzing the relative importance of soil content and location on the variation in vegetation composition.
Germination success was studied on Vaccinium myrtillus, a dominant species of the understorey of several northern hemisphere ecosystems, which may be suitable for revegetaion along this road. Trials were conducted in growth chambers under different experimental conditions: variable light qualities and ingestion or non-ingestion by bears as pre-treatment.
Two years after deposition of topsoils, the vegetation cover was generally satisfactory from an aesthetical point of view. However, the variation in vegetation cover and species composition was considerable on different topsoils, reflecting both local variations of indigenous vegetation and soil quality. Most of the species with decreasing abundance from the first to the second year could be considered as africultural weeds, while most of the species with increasing abundance often inhabit forests and forests edges.
On the roadside, the vegetation composition rapidly (after two years) reached a rather stable state. Three years after soil redistribution, the vegetation composition was related to the soil parameters and explanatory factors such as slope and aspect of the site, and distance to the road. No effect of fertilisation on the vegetation composition was observed along the roadside.
Vaccinium myrtillus germinated under all treatments, although germination was reduced when incubated at high levels of far red light, imitating tree canopy, as well as after being ingested by bears.
We conclude that restoration of degraded rural areas in comparable environments benefits from the use of natural revegetation from indigenous topsoil in terms of vegetation cover, vegetation composition and heterogeneity.

Key words:
Revegetation, restoration, roadside, topsoil, indigenous vegetation, boreal forests, prorpagule bank, Vaccinium myrtillus, germination, light quality.



Oppdatert: 22.04.05
Utskriftsvennlig versjon : Arkiv : Tips en venn