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 a vital source of information in addressing critical ecological and conservation issues. These data now allow researchers to attain key insights more rapidly and at larger scales. An important source of biodiversity data comes in the form of citizen science initiatives. iNaturalist is one of the most popular naturalist citizen science platforms and is being increasingly used in biodiversity research, including monitoring species distributions, biological invasions, at-risk species, phenological changes, and even investigating a wide variety of interspecific interactions. Still, iNaturalist is ultimately an unstructured, citizen science platform, resulting in a number of sampling artifacts and other sources of error that must be taken into consideration by researchers. These commonly include spatial, temporal, and taxonomic biases in observations logged by the public. Here we outline and highlight these important sources of error in iNaturalist data using case studies that span various ecosystems and taxa in the United States. Together, we provide comprehensive guidance, suggestions, and notes for caution in using iNaturalist data to better help scientists leverage this dataset for future ecological and conservation research.