This dataset comprises enchytraeid worm abundance and Delta 13C values from enchytraeid cholesterol. The data were collected as a component of the NERC Soil Biodiversity Programme, consisting of a one year study of the diversity and activity of Enchytraeid worms, small relatives of the earthworm. These worms are very common in upland soils and often outweigh all other fauna, including sheep. The project focused on investigating the importance of Enchytraeid species, or group diversity, in maintaining soil carbon cycling. The NERC Soil Biodiversity Thematic Programme was established in 1999 and was centred upon the intensive study of a large field experiment located at the Macaulay Land Use Research Institute (now the James Hutton Institute)'s farm at Sourhope in the Scottish Borders. During this time, the site was monitored to assess changes in aboveground biomass production (productivity), species composition and relative abundance (diversity). Full details about this dataset can be found at https://doi.org/10.5285/0a443a55-28b6-4d82-9042-5a35bfdbebe0
