This dataset contains information regarding mountain river sites sampled in 2016-17. It includes: 1) physicochemical parameters of the river sites sampled, 2) tensile-strength loss data of a standardised cotton strip assay as a proxy for the decomposition of cellulose in mountain rivers, 3) molecular next generation sequencing data of the fungal Internal Transcribed Spacer region (ITS) and Cellobiohydrolase I gene (cbhI) sampled from the cotton strip decomposition assay. Field observations were made in Alaska, Austria, Ecuador, France, New Zealand and Norway to investigate how decreasing catchment glacier cover influences the fungal decomposition of organic matter in mountain rivers. Full details about this dataset can be found at https://doi.org/10.5285/fec704d2-ee6a-427b-9345-850dd96ff1b4
