Ecological monitoring with citizen science: the design and implementation of schemes for recording plants in Britain and Ireland

Interest in citizen science has been increasing rapidly, although the reviews available to date have not clearly outlined the links between the long-established practice of recording plant species' distributions for local and national atlases, or other recording projects, and the gradual development of more structured monitoring schemes that also rely on volunteer effort. We provide a review of volunteer-based plant monitoring in Britain and Ireland, with a particular focus on the contributions of expert volunteers working with biological recording schemes and natural history societies; in particular, we highlight projects and practices that have improved the quality of data collected. Although the monitoring of plant distributions at larger scales has led to numerous insights into floristic change and its causes, these activities have also led to the recognition that knowledge of species' abundances at finer-scales often provides a more powerful means of detecting and interpreting change. In the UK, this has led to the development of a new, abundance-based National Plant Monitoring Scheme'. We outline this new structured scheme, and review some of the design considerations that have been made during its development. New monitoring projects require a clear justification, and the launch of a new scheme is also an opportune moment to review whether some basic assumptions about the collection of monitoring data can withstand scrutiny. A distinction is often made between monitoring that is focused on answering particular, focused questions, and that which is more generally seeking to detect changes; for example, in species' distributions or abundances. Therefore, we also review the justification for such general surveillance' approaches to the monitoring of biodiversity, and place this in the context of volunteer-based initiatives. We conclude that data collected by biological recorders working within atlas or monitoring scheme frameworks will continue to produce datasets that are highly valued by governments, scientists, and the volunteers themselves.