Longevity of arctic and alpine clonal plants
Arctic and alpine regions, characterized by cold climates, are expected to be vulnerable to climate warming and land use change. In these habitats, vegetative reproduction and slow growth enable most plants to survive long periods of time, in which harsh environmental conditions hamper sexual reprod...
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| Other Authors: | , |
| Format: | Thesis |
| Language: | English |
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2011
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| Online Access: | http://edoc.unibas.ch/diss/DissB_10213 https://edoc.unibas.ch/23865/ https://edoc.unibas.ch/23865/1/LdeWitte_Thesis.pdf https://doi.org/10.5451/unibas-006055914 |
| Summary: | Arctic and alpine regions, characterized by cold climates, are expected to be vulnerable to climate warming and land use change. In these habitats, vegetative reproduction and slow growth enable most plants to survive long periods of time, in which harsh environmental conditions hamper sexual reproduction. Based on the discovery of extremely old plants and the presence of Ôremnant populationsÕ that were found to persist despite negative growth rates, extended longevity of plants is believed to enlarge persistence of populations and to have a positive relationship with ecosystem functioning. The main objectives of this PhD thesis were to assess present knowledge on longevity of clonal plants and the methods used to measure it, as well as to generate high-quality lifespan data for clonal plant species that dominate late-successional alpine-arctic vegetation based on genet size data and annual horizontal growth measurements. Additionally, the results were used to assess population persistence, community stability and ecosystem resilience under past and future global change. The annual horizontal growth measured in the field was compared among species, successional stage, regions and years to investigate the influence of geographically or temporally variable climates. The lifespan investigations conducted during this thesis revealed extreme longevity for several plants in late-successional vegetation as well as in pioneer sites. With the applied indirect methods, it was possible to observe genet age structures of whole populations that indicated high turn over rates and healthy population dynamics allowing adaptation to changing climates. Clonality, slow growth, longevity and continuous genet turnover all together form the combined strategy of arctic-alpine clonal plants to cope with their harsh environment. In the meantime, they enhance community stability and ensure maximum ecosystem resilience. Therefore, it can be predicted that populations of clonal and long-lived plants will persist despite future climate ... |
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