A species by quadrat matrix showing the percentage cover of understory herbaceous plants in ancient and recent woodlands varying in age and isolation. Percentage cover was calculated for each species individually. The data was collected on the Isle of Wight, woodlands spanned the entire island and were not situated in one area. All data was collected in the summer of 2021 over a period of 3 weeks covering the last 2 weeks of may May and the first week of June. This time was chosen as this is when a large subset of woodland plants are in flower. Woodlands were sampled in blocks of three, each block contains an ancient woodland, a recent woodland adjacent to the ancient woodland and another recent woodland of similar age and size but isolated from the ancient woodland. Each woodland had six quadrats taken, systematically placed at four corners and two in the centre. Within each quadrat the percentage cover of all understory herbs was recorded. This data was collected to measure the colonisation credit of recently planted woodlands, and to observe how much this might vary under differing degrees of isolation. This data could also be used to compare all sorts of biodiversity metrics between connected and isolated recent woodlands. It could also be used to compare beta diversity metrics between woodlands of varying degrees of isolation Full details about this dataset can be found at https://doi.org/10.5285/7c2b2878-1d15-4ddd-9d7e-cf50bd65f652