This dataset contains botanical data 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 heathland and calcareous grassland sites the percentage cover of all plant species were recorded within five 1m quadrat squares. Plants were recorded to species level where possible, or genus where species level was not possible. Covers of bare ground and litter were also recorded. Within woodlands plots, sampling was done slightly differently to enable recording of ground level plants and species within multiple canopy levels. Cover and presence of all herbaceous species were recorded in 2m quadrat squares, cover of tree seedlings (<1.5 m height) were recorded in 5m quadrat squares and ground-level cover of trunk of tree species if necessary were recorded in 10m quadrat squares. 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/10.5285/8a75395f-7858-40a2-8364-eb3482aeaad1