Vegetation composition data from a series of former nitrogen deposition experiments in the UK, 2000-2021

For the data rescue project "Rescuing UKREATE Data to Elucidate Recovery" (RUDER), UKCEH engaged a consortium of stakeholders, asking members to share publications and available data on the experimental design and potential recovery indicator variables for a suite of former N deposition experiments across a variety of priority habitats. We received data in various formats and file types from the consortium members. We adopted a stepwise approach in vegetation data harmonisation. First, we identified the characteristics of the submitted vegetation information (data and/or publications) across the different experiments e.g. years and/or frequency of collection, variation in the clarity of accompanying metadata, response metrics. Where sufficient information existed, we then used the in-development experimental design spreadsheet to match unique IDs to submitted data for those experiments where it proved possible. Where this proved impossible, we ascertained next steps to help understand the experimental design (e.g. Thursley or Tadham Moor) or rescue data from literature (e.g. Wardlow Old and New). Initial QA procedures have been implemented to test standardisation of the species names and quality of the species cover data. We automated the data collation procedure so that in each experiment, data have been collated into a standardised format of response i.e. species percent cover. Where possible the vascular plant species names were matched with BRC (Biological Records Centre) code from PLANTATT (Hill et al. 2004). This allowed harmonization of data as this picked up where genus only codes were used, or the same species was spelled in different ways across datasets. Species names were then harmonized for the final dataset to use the taxon name present in PLANTATT (for vascular plants). A similar scheme was adopted for bryophytes, using information within BryoAtt (Hill et al. 2007). Lichen species codes (BLS code) were found using the British Lichen Society webpage resource (https://britishlichensociety.org.uk/; accessed on 8th May 2026) and entries looked at individually to harmonise within and across experiments. In quality assuring the vegetation data, we note the following information relating to species groups and other features (e.g. bare ground) that are recorded in each experiment (Table 6). In those experiments where species groups were recorded and there is zero cover of that group, or species within that group, this is a 'real' zero. In those experiments where there is no evidence of species groups being recorded, it is unknown whether they are real zeros or that they were not examined and could therefore be present but were not noted. These properties of the data should be borne in mind when analysing them.