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Applying molecular methods to investigate potential anthropogenic impacts on ageing in a free-living bat species Scott Brown (21042521) Bats Myotis bechsteinii Epigenetics Microbiome Ageing DNA methylation Urbanisation is a pervasive driver of global change and whilst direct impacts on wildlife are often clearly visible, the indirect impacts are diAicult to detect using traditional ecological metrics. For habitat specialist species, sensitive to disturbance, subtle changes at the molecular and microbial level may provide an early indication of population-level impacts. This thesis examines whether diAerences in ageing and gut microbiome between two colonies of Bechstein’s bat (Myotis bechsteinii), a long-lived woodland specialist and urban avoider are consistent with anthropogenic stress exposure. In Chapter 2, DNA methylation at age associated cytosine-phosphate-guanine (CpG) sites was measured to develop and validate an epigenetic ageing model for M. bechsteinii. A CpG-based epigenetic clock was constructed using 12 biomarkers from four genes and evaluated using leave-one-out cross-validation, demonstrating accurate within-sample age prediction. Although the model was based on a limited number of CpG sites, representing a reduced resolution when compared to larger models, this clock allowed for comparisons between colonies and revealed site-specific diAerences in methylation patterns. Evidence was found of individuals from a more anthropogenically disturbed woodland exhibiting indicators of epigenetic age acceleration when compared to those from a less disturbed woodland, suggesting an influence of environmental stressors on biological ageing. In Chapter 3, shotgun metagenomic sequencing was used to characterise the gut microbiome of bats from both colonies. Metagenome assembled genomes (MAGs) were reconstructed and functionally annotated to assess taxonomic composition, diversity and inferred metabolic capacity. Despite high interindividual variability, there were no clear diAerences in overall microbial diversity and functional potential between sites and across ages. However, subtle shifts in the relative abundance of specific bacterial taxa and functional traits were detected between colonies, indicating local environmental structuring without overt imbalance in the microorganisms comprising the microbiome. Together these chapters demonstrate that epigenetic and microbiome-based approaches can reveal cryptic physiological responses to diAering environmental pressures in wild populations. This thesis highlights the potential of molecular biomarkers as sensitive tools for conservation monitoring and underscores the importance of mitigating cumulative stressors from urban-adjacent environments.<p></p> 2026-05-27T00:00:00Z Text Thesis 10779/exe.32473665.v1 https://figshare.com/articles/thesis/Applying_molecular_methods_to_investigate_potential_anthropogenic_impacts_on_ageing_in_a_free-living_bat_species/32473665 All rights reserved Open Access after 2027-11-26