The use of iNaturalist in ecological and conservation research: methodological guidance and considerations

Faced with ever-accelerating threats to Earth’s biodiversity, large digital datasets have become essential for ecological research and informing conservation policy. These data now allow researchers to attain key insights more rapidly and at larger scales. An important source of biodiversity data comes from citizen science initiatives. iNaturalist is one of the most popular global citizen science platforms and is being increasingly used in biodiversity research, including monitoring species distributions, biological invasions, at-risk species, phenological changes, and a wide variety of interspecific interactions. Still, iNaturalist is ultimately an unstructured citizen science platform, resulting in a number of sampling artifacts and biases that must be taken into consideration by researchers. Using case studies from the United States, where platform usage is highest, we illustrate these principal sources of error, which include significant spatial, temporal, and taxonomic skews in observations. For each issue, we identify both high- and lower-risk applications and provide recommendations for diagnosis and mitigation. Together, we offer guidance on how researchers and managers can best match their questions to the strengths of the iNaturalist platform and how to apply appropriate corrections or use iNaturalist to complement additional data sources. With informed, deliberate use, iNaturalist can continue to reliably support evidence-based ecological and conservation work worldwide.