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Ecology and population genetics of the neophyte alien, Hoary Mustard (Hirschfeldia incana (L.) Lagreze-Fossat). / Reshma Patel
Swansea University Author: Reshma, Patel
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The invasion of natural habitats by alien plant species is now recognised as one of the most important factors contributing to the current loss of biodiversity in our planet. In the UK alone there are now approximately equivalent numbers of alien and native plant species (Stace, 1997), and a small n...
|Degree level:||Master of Philosophy|
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The invasion of natural habitats by alien plant species is now recognised as one of the most important factors contributing to the current loss of biodiversity in our planet. In the UK alone there are now approximately equivalent numbers of alien and native plant species (Stace, 1997), and a small number of these are spreading in rural and urban areas. This study looked at Hirschfeldia incana (L.) Lagreze-Fossat belonging to the family Brassicaceae. Commonly known as Hoary Mustard, it is an established wool, grain and bird-seed alien in the UK. H. incana is native to southwest Europe, the Mediterranean region and southwest Asia. In the UK, this neophyte alien has shown a significant (p=0.004), exponential increase in its spread from 1930 to the year 2000. In this investigation a number of H. incana populations in South Wales were studied, in terms of the communities they were associated with, in semi-natural and natural habitats. The three species most commonly associated with H. incana were Senecio jacohaea, Holcus lanatus and Medicago lupulina, all native to the British flora. Cluster analysis and TWINSPAN indicated three major types of habitats, open urban gap habitat, closed habitat (semi-natural) and sand dune habitat (natural). Species indicative of the three habitats were Mycelis mural is (open urban gap). Euphorbia peplus (closed) and Ammophila arenaria (sand dune). Random amplified polymorphic DNA (RAPD) data was collected for England, Wales and southern European populations. Estimated genetic diversities were calculated using Shannon's Index, and showed that diversity was similar in native and alien populations (p=0.271 for H'j, and p= 0.018 for Hj). The genetic diversities between populations compared well with those for other outcrossing plants. The distinct clusters of populations found in the British Isles together with the evidence obtained from the RAPD data suggests that founding populations probably originated from multiple source populations.
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