Abstract
The introduction of non-native species represents a key component of global environmental change and is now recognized as the second biggest threat to global biodiversity after habitat destruction. Aspects of both the ecology and genetics of the invasive algae, Sargassum muticum from the Welsh coastline were investigated with a view to generating information necessary for potential future management strategies for this non-native alga. Based on the DNA sequencing markers investigated, both the invasive and native populations of S. muticum display low variability. Analysis of the TrnW_I mitochondrial intergenic spacer regions revealed the occurrence of a previously unrecorded haplotype from the native range. Although sequence data could not pinpoint precise sourcelocations, distribution of both the TrnW_I and cox 3 haplotypes suggested regions of central Japan as a likely source area. Amplified fragment length polymorphisms (AFLPs) were also trialed as an additional method for examining the invasion genetics of the alga.
However, contrary to previous studies of macroalgae, the development of AFLPs for S. muticum in this investigation was hindered by a lack of reproducibility attributable to the quality of the DNA. Hence, it is suggested that in future studies, more stringent DNA purification procedures may help resolve the problems of reproducibility. Results from the population ecology investigations demonstrated variability in plant morphology dependent on environmental conditions. Growth and reproductive phenology of the alga within Wales appears similar to other introduced populations within the UK, although there was variability5 in the extent of fertility between contrasting habitats. Comparisons of the associated epibiota of S. muticum and structurally similar native seaweed hosts from two contrasting locations in Wales were also examined. Contrasts in community structure and species composition were most evident between sample locations indicating a significant impact of environmental conditions on epibiota assemblages. With regards to the
associated epifauna, the native alga, Cystoseira spp. at Rhosneigr supported a community very similar to that of the invader, a result attributed to the overall similar morphological complexity of the two macroalgae. In contrast, at Tal y Foel, the native alga Fucus vesiculosus supported a different and less diverse assemblage of associated epifauna compared to S. muticum. The ecological and molecular data are discussed in light of the current knowledgebase of S. muticum and in the context of the management of non-native marine species within Wales.
| Date of Award | Sept 2012 |
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| Original language | English |