Abstract
Volunteer-based plant monitoring in the UK has focused historically on distribution mapping, with less emphasis on the collection of data on plant communities and habitats. However, abundance monitoring for other groups of organisms is well-established, e.g. for birds and butterflies, and UK conservation agencies have long desired comparable schemes for plants. We describe the first nine years of a new plant citizen science scheme for the UK, the 'National Plant Monitoring Scheme'. Scheme development emphasised volunteer flexibility through co-creation and feedback, whilst retaining a rigorous approach to sampling design. Comparisons with professional surveys have allowed for an understanding of the likely biases inherent to our approach, and model-based adjustments for these are being explored. Understanding the strengths and limitations of the NPMS will guide development, increase trust in outputs, and direct efforts for maintaining volunteer interest, as well as providing a set of ideas for other countries to experiment with.
