Hoffmann, F. (1999) Restoration processes in a calcareaous grassland after abandonment of arable fields at the Baltic island of Öland. Bachelor's Thesis, Biology.
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Abstract
Two moments in the course of vegetation processes taking place after the abandonment of formerly cultivated fields at the species rich alvar dry grasslands on the Baltic island of Oland (Sweden) were studied. After 50 years of natural restoration not all species had returned. Twelve missing species were sown into the field and the local species pool was investigated. Eleven species emerged and survived one growing season. Short-term establishment was possible and diaspore dispersal seems to be the limiting factor for species returning. In the local species pool occur 160 characteristic species, including all missing species. After 85 years Juniperus communis forms an almost closed woodland. The seed bank of small open places inside the woodland contained not more than 31 species in total. In the open places and in places at the edge of the woodland, flowering intensity and light availability were measured. Both were lower inside. Disappearance of grassland species in the open places seems to be initiated by a decreased reproduction due to less flowering caused by shadowing by the junipers. Seed production is decreased and the seed bank depleted. When shrub cutting is done as restoration measure, returning of species has to come from seed dispersal since only few species survive in the seed bank or vegetatively. Restoration of dispersal possibilities for plant species should be included in restoration measures of calcareous grasslands and other habitats. Artificial reintroduction is an option that should be considered more. This study is an example of research about the restoration processes in habitats related to traditional agricultural systems. More knowledge about these systems has to be gained in order to restore and maintain them.
| Item Type: | Thesis (Bachelor's Thesis) |
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| Degree programme: | Biology |
| Thesis type: | Bachelor's Thesis |
| Language: | English |
| Date Deposited: | 15 Feb 2018 07:45 |
| Last Modified: | 15 Feb 2018 07:45 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/9485 |
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