Development of a robust, standardised protocol for monitoring the distribution, abundance, and ecology of the Freshwater Pearl Mussel, M. margaritifera

Resumo

Margaritifera margaritifera is an endangered, long-lived, and culturally significant freshwater mussel in the Unionidae family. The species has suffered major declines, particularly in Northern Europe, where it is under risk of extinction in many countries. Surveying for M. margaritifera using traditional methods is challenging. It is camouflaged, rare, and often buries under sediment, and alternative survey tools would be of benefit. Environmental DNA (eDNA) surveying involves sampling from the environment under the assumption that DNA from organisms of interest will be collected should they be/have been present. eDNA has been applied in the case of M. margaritifera previously, but further validation and synthesis is needed, and there are more areas to investigate, such as reproduction. Thus, if, and precisely how eDNA can inform the presence/absence of M. margaritifera at sites of interest, and abundance, distribution, and reproductive activity will be addressed here. This also advances eDNA surveying toward widespread practical implementation.
Chapter 1 assesses M. margaritifera and its current condition and threats in Scotland. Then, eDNA, its implementation, limitations, and potential applications are reviewed. Chapter 2 notes the methods applied through further chapters, and briefly the mesocosm test used to optimise and validate if, originating from Carlsson et al., 2017. Chapter 3 trials the identification of a field-based collection method based on traditionally surveyed sites in small rivers. Chapter 4 studies eDNA concentration variation of two significant M. margaritifera populations over time. An ~8 fold difference in eDNA concentrations was recorded between seasons, and a significant spike in eDNA related to gamete and larva release was detected, potentially key to conservation practitioners. Chapter 5 investigates the complex relationship between eDNA and organism abundance/distribution, giving some evidence of an analysable relationship, with significant barriers to useability. Chapter 6 assesses the practicality of applying this tested method to aid conservation professionals via examples in Strathspey and Alladale. Chapter 7 indicates progress and provides suggestions and recommendations, both for M. margaritifera surveying, and eDNA more widely.

Data do prémio	10 out. 2025
Idioma original	English
Instituição de premiação	University of the Highlands and Islands
Supervisor	Bernd Hänfling (Supervisor), Lucio Marcello (Supervisor) & Barbara Morrissey (Supervisor)