Biology subjects

Blackman, R.

Publications and source records attributed to Blackman, R..

2 recordsLinked to original sources

bioRxiv2023

Mussels on the move: new records of the invasive non-native quagga mussel (Dreissena rostriformis bugensis) in Great Britain using eDNA and a new probe-based qPCR assay

Invasive non-native species (INNS) pose a worldwide environmental threat, negatively impacting invaded ecosystems on an ecological and economical scale. In recent decades, quagga mussels (Dreissena rostriformis bugensis) have successfully invaded several countries in Western Europe from the Ponto-Caspian region, being recorded for the first time in Great Britain (GB) in 2014, in Wraysbury, near London. In recent years, environmental DNA (eDNA) analysis has proven to be a sensitive and effective method for early detection and monitoring of a number of INNS. Previously, a dye-based quantitative PCR (qPCR) assay was developed for the detection of quagga mussels from eDNA samples. Here, a target-specific probe was designed to further increase the specificity of this assay and used to obtain an updated distribution of this species in GB. Twenty-four sites were sampled, including sites with established populations near London and sites spread across the East Midlands and East Anglia regions. Positive detections were obtained for 11 of the 24 sites, and these were widely spread, as far as Nottingham (East Midlands) and Norfolk (East Anglia). Detection rates were 100% at the three sites with known established populations, while rates were lower (3-50% of positive replicates) in the eight newly-identified sites, consistent with an early stage of invasion. Of particular concern was the detection of quagga mussels in major waterways and in popular recreational sites, highlighting urgent measures are needed to control pathways and spread. Our study demonstrates that quagga mussels are considerably more widespread in GB than previously thought and provides a much-needed step towards operational use of eDNA for monitoring quagga mussels.

ecology↗

bioRxiv2018

Temporal and spatial variation in distribution of fish environmental DNA in England’s largest lake

Environmental DNA offers great potential as a biodiversity monitoring tool. Previous work has demonstrated that eDNA metabarcoding provides reliable information for lake fish monitoring, but important questions remain about temporal and spatial repeatability, which is critical for understanding the ecology of eDNA and developing effective sampling strategies. Here, we carried out comprehensive spatial sampling of Englands largest lake, Windermere, during summer and winter to 1) examine repeatability of the method, 2) compare eDNA results with contemporary gill-net survey data, 3) test the hypothesis of greater spatial structure of eDNA in summer compared to winter due to differences in water mixing between seasons, and 4) compare the effectiveness of shore and offshore sampling for species detection. We find broad consistency between results from three sampling events in terms of species detection and abundance, with eDNA detecting more species than established methods and being significantly correlated to rank abundance determined by long-term data. As predicted, spatial structure was much greater in the summer, reflecting less mixing of eDNA than in the winter. For example Arctic charr, a deep-water species, was only detected in deep, mid-lake samples in the summer, while littoral or benthic species such as minnow and stickleback were more frequently detected in shore samples. By contrast in winter, the eDNA of these species was more uniformly distributed. This has important implications for design of sampling campaigns, for example, deep-water species could be missed and littoral/benthic species overrepresented by focusing exclusively on shoreline samples collected in the summer.

ecology↗