PhD defence: Reki Kardiman
Reki Kardiman defends his thesis,
Habitat types, species autecology and restoration of tropical rainforests in Sumatra, Indonesia
Senior Researcher Anders Ræbild, IGN
Dr Tom Swinfield, Royal Society for Protection of Birds, UK
Associate Professor Dan Bruhn, Department of Chemistry and Bioscience, Aalborg University
Professor Frans Bongers, Department of Environmental Sciences, Wageningen University & Research - The Netherlands
Professor Henrik Meilby (chair), IFRO
This thesis studies the autecological adaptations of tree species to different microhabitat conditions in an effort to progress our understanding of where restoration planting is most successful and why. I firstly investigate which habitat types and which species potentially increase restoration success. Restoration in shrub dominated areas, severely degraded forests and areas surrounding bamboo must be prioritized, while areas inside bamboo dominated vegetation should be avoided. In each habitat type, a proper species selection is suggested as only few species were found to be well performing in all habitats. Secondly, I assess the early response of several late successional species to sudden light and shade exposure. Photo-inhibition occurred on all species when they were exposed to high light, but showed some recovery by photo-acclimation within a week. While height growth generally was largest under shade, diameter growth was fastest under high light. Species perform differently with in response to sudden changes in light environment. Thirdly, I investigate the change of stomatal parameters (size, density and rate of opening) of Sumatran late successional in shade and light situations. Species with small stomata had numerous stomata on the leaf surface. Small stomata opened faster than large stomata and the rates differed for plants acclimated to shade and light. Species with fast stomatal opening showed fast biomass growth. As the last part, I compare multiple species planting with natural plant diversity in each type of vegetation defined in Study I. Planting had a positive effect on plant diversity in all types, but less so in selectively logging forest where the natural regeneration was very diverse. My hope is that the thesis will contribute to developing of a concept for improving forest restoration with large numbers of species, to increase the possibility of restoration success in South East Asia and across the tropics.
The thesis is available for inspection at the PhD administration office at Rolighedsvej 23.