Staff Thesis 335 views 116 downloads
Spatial and seasonal distribution patterns of native and introduced aquatic species based on environmental DNA
Swansea University Author: Teja Muha
PDF | E-Thesis – open accessDownload (7.13MB)
DOI (Published version): 10.23889/suthesis.52895
The analysis of environmental DNA (eDNA; DNA recovered from environmental samples) is a recently developed non- invasive method used for detecting aquatic invasive and native species. Combined with barcoding or metabarcoding can be used to identify the presence of a target organism or to analyse an...
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The analysis of environmental DNA (eDNA; DNA recovered from environmental samples) is a recently developed non- invasive method used for detecting aquatic invasive and native species. Combined with barcoding or metabarcoding can be used to identify the presence of a target organism or to analyse an entire community, by estimating species presence/ absence and relative abundance, providing information for aquatic species management. The main aim was the optimisation of eDNA methods for assessing spatial and seasonal distribution of aquatic native and invasive species, focusing on hotspots of marine invasive species and on the distribution of fish species in rivers. An initial study on optimisation of eDNA capturing protocols, determined that sampling a large but feasible volume of water by combining syringe filtration with ethanol- sodium acetate precipitation was the most optimal strategy. Using this method of eDNA extraction and metabarcoding, a second study analysed river restoration success, after a recently removed weir, to identify changes in the abundance of freshwater fish, with no evidence of weir impacting fish discontinuity patterns, before or after removal. A similar approach analysing the role of obstacles on fish distribution in rivers with contrasting levels of fragmentation, indicated that both natural and artificial barriers resulted in limited fish community composition upstream compared to downstream, particularly for non-migratory species, with the migratory salmonid species being able of upstream passage in both of the rivers. Finally, the application of eDNA and barcoding for early detection and monitoring of invasive seaweed, indicated that native and invasive Codium spp. displayed significant seasonal and spatial differentiation, which could explain the establishment success of the non-native species. The results of this thesis establish the usefulness of environmental DNA spatial and seasonal dispersal assessment of aquatic species and suggests new avenues for eDNA future applications, such as providing data for spatial modelling.
Molecular ecology, environmental DNA, sequencing, spatial assessment, barcoding, metabarcoding, invasive species