This thesis is an investigation into the genetic diversity, genetic structure and phenotypic differentiation of the rare plant Melampyrum sylvaticum L. (Orobanchaceae) in the United Kingdom, in the context of habitat fragmentation. Habitat fragmentation is of conservation concern as it may result in reduced population sizes, reduced genetic diversity and gene flow, and altered environmental and ecological conditions. Seven polymorphic microsatellite markers were developed and revealed that M. sylvaticum is highly inbreeding (FIS = 0.90). Ten populations in a fragmented landscape in Scotland had significantly less genetic diversity than eight large populations from Scandinavia where the species’ habitat is more continuously distributed. Overall, genetic differentiation between populations was very high (F’ST = 0.892). Furthermore, the use of a replicated, spatially explicit sampling scheme revealed that ‘fragmented’ Scottish sites had much stronger spatial genetic structure (Sp = 0.267 – 0.311), per unit area, than more continuously distributed sites (Sp = 0.026 – 0.096) in Sweden. These genetic data indicate that the fragmented populations of M. sylvaticum have low genetic diversity and that gene flow is very low. To quantify morphological differences among populations, plant phenotypes were described using a novel method based on count and architectural position data of ecologically-relevant fitness-related traits. Four populations in the UK were phenotypically differentiated in their whole-plant, vegetative and reproductive phenotypes. Vegetative phenotypes correspond to traditionally recognised ‘seasonal variants’ in the Orobanchaceae and are likely to represent ecotypic local adaptation. The number of ‘unsuccessful’ and ‘potentially successful’ reproductive traits was significantly different among populations. It is not possible to say whether this is due to site-specific resource effects or population-specific inbreeding depression. Horticultural protocols were developed to enable conservation actions to be carried out with greater success. Recommendations for the conservation management of the species are to focus on site-based management, local expansions and ex-situ conservation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:569599 |
| Date | January 2012 |
| Creators | Crichton, Rhiannon Jane |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=192163 |
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