Not just species recording: the potential of citizen science for habitat monitoring.

Context: Reversing the global biodiversity crisis requires not only conservation and management of species, but the habitats in which they live. While there is a long history of biodiversity recording by volunteers, at least in Europe, information on habitats is less frequently recorded. Habitat data is needed to map and monitor habitat extent and condition; to train and validate earth observation (EO) data; and to explain biodiversity change. The complexity of habitat classifications means that it is challenging to record habitat well, but citizen science provides diverse opportunities to improve the range and scale of habitat recording. Objectives/Methods: We reviewed how citizen science can complement surveys by professionals and EO for habitat recording, and discuss its opportunities and challenges. We summarised a survey of 458 volunteer biodiversity recorders asked about their interest in and barriers to recording habitat. From this we developed a framework of questions to design citizen science that is appropriate and effective for habitat recording. Results/Conclusions: We found that existing biodiversity recorders were willing to consider habitat recording, but many lacked confidence and some lacked motivation. Our framework of six questions addresses the interplay between volunteer motivation and confidence, and data accuracy. It highlighted design considerations such as clarity of purpose, cost to volunteers, protocol complexity and scale of sampling. This impacts the training and support required by volunteers. Building this understanding into citizen science design enables us to develop activities that meet the needs for habitat data for monitoring, EO validation and research. Supplementary Information: The online version contains supplementary material available at 10.1007/s10980-025-02155-4.