Contains 3 files. One spreadsheet containing processed sequences -SM1_results_spreadsheets The other two containing Read 1 and Read 2 of the raw sequences (fastq). Abstract A major challenge in the study of Quaternary environments is the variable preservation of paleoenvironmental evidence at many locations. Using ancient DNA from sediment cores (sedaDNA) allows the reconstruction of past biodiversity patterns at locations where traditional techniques often only reveal a partial picture. To test the feasibility of this approach, we analysed a sediment core from a peat bog, Traeth Mawr, in the Brecon Beacons National Park. Plant DNA was extracted and subjected to DNA metabarcoding, combining the use of universal PCR primers with Next-Generation Sequencing, to analyse a 7-143bp segment of the chloroplast trnL gene in five temporally separated sections of the core. Pollen analyses, from sections of the core, provide a comparison between the sedaDNA results and more traditional methods for studying the paleoenvironment. Partial reconstruction of past environmental variation was possible with the recovery of 113,682 DNA sequences representing six plant families, adding complementary results to traditional pollen analysis. This study is the first in the UK to successfully report the sequencing of ancient plant DNA from terrestrial sediments (currently a peat bog) using a DNA metabarcoding approach and exemplifies a promising area of research for addressing a range of questions about Quaternary environmental change.