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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Scottish liverwort heath : response to a changing environment and prospects for the future

Flagmeier, Maren January 2013 (has links)
Upland plant communities are vulnerable to environmental change, especially if the component species have limited dispersal abilities and consist of fragmented populations. Oceanic-montane liverwort-rich heath is a rare upland vegetation type found in the oceanic areas of the British Isles and Norway. This thesis contributes both fundamental knowledge about the liverworts’ biology and an understanding of how this can be applied in conservation management, taking into account the compositional changes that have already occurred within liverwort heath. These issues were explored by i.) a re-survey of 50- and 20-year old liverwort heath plots, ii.) assessment of the genotypic diversity of one liverwort using microsatellite markers, iii.) ex-situ and in-situ experimental studies on growth and reproduction and, iv.) transplantation of one liverwort to unoccupied sites to assess habitatlimitation and the potential of translocation as a conservation management tool. The re-survey revealed that the liverwort heath has undergone compositional changes. Liverworts and dwarf shrubs decreased while graminoids increased. This was linked to grazing pressure, eutrophication and warmer and drier conditions. High genotypic diversity was demonstrated in a liverwort unknown to reproduce sexually in the British Isles (Anastrophyllum alpinum), suggesting that sexual reproduction must have occurred in the past. The data also indicated clonal growth at the local level, but no dispersal of vegetative fragments between populations. Thus, dispersal limitation is likely to have implications for the species under future environmental change. Ex situ and in situ cultivation of whole liverworts and fragments revealed that most of the species can grow from both fragments and whole shoots. Therefore, in the absence of sexual reproduction, the species can persist locally by growth and vegetative spread. Also, there is potential for ex situ conservation of these species, in situ enhancement of existing populations, and creation of new ones. Translocation of Herbertus hutchinsiae suggested that the species is dispersal limited. Transplants grew at all sites, exhibiting best growth within range. Therefore, translocation is a management option for this species to enhance or increase extant populations, to restore populations that have declined over the last half century and to reach future suitable climate space. These results have large implications for nature conservation management, to safeguard the unique liverwort heath.

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