This dataset contains carbon and nitrogen data from soils and vegetation from 13 calcareous grassland, 13 heathland and 12 woodland sites within Dorset, UK. The sites were selected to represent a range of habitat types across a condition gradient as measured by levels of degradation from the original habitat. The original habitats were identified as being calcareous grassland, heathland or woodland from a survey conducted in the 1930s. Within each site, 15cm deep soil cores were taken and analysed for total nitrogen, total carbon and bulk density. Within the same area for each site, vegetation samples were taken from five 50cm quadrats and separated into herbacous or shrub layers before analysis for total carbon, total nitrogen and dry weight. Heathland and calcareous grassland sites were visited in summer 2017 and woodland sites were visited in summer 2018. Full details about this dataset can be found at https://doi.org/10.5285/ea43c2d1-88f5-4692-a09d-0ef4d96e0f35