Generating Red Lists with the support of citizens science

In Switzerland, extensive data collection by volunteer field botanists has a long tradition. Indeed, there are many excellent field botanists in this country who like to share their floristic observations. This represents an incredible potential for specific data sampling. During the last revision of the Swiss Red List of vascular plants, published in 2016, InfoFlora decided to switch from an expert-based Red List to an evidence-based Red List. This important step could only be taken thanks to the great potential of voluntary work. As a result, 420 volunteer botanists visited more than 8,000 sites where the country's 713 rarest and most endangered species are found. This success story has motivated InfoFlora to continue the cooperation with the ‘Swiss botany community’ in a permanent way. Within a scientific data sampling framework, InfoFlora offers appealing ‘data sampling missions’ for the volunteers. Currently, missions are being promoted to update the Red Lists of vascular plants and charophytes.

To motivate botanists to participate actively in this large-scale endeavour, InfoFlora has developed a wide range of tools and opportunities. These include field missions accessible directly through a smartphone application, guided excursions, and identification workshops. In addition, various training courses are organised to improve the volunteers’ skills in recognising challenging taxa. Manuals and guidelines have been created to help volunteers carry out specific tasks in a consistent manner. Continuous validation of submitted observations—particularly those relevant to the Red List update—is carried out by experienced botanists to ensure the overall quality of the dataset.

This methodology significantly increases the volume of available data while maintaining a robust standard of data quality. It also addresses taxonomic bias by encouraging greater interest in overlooked taxonomic groups such as charophytes, thereby filling data gaps and expanding collective knowledge. Nonetheless, external mandates remain necessary for particularly complex investigations, demonstrating that volunteer work and paid specialist work are complementary rather than replacing each other.