Citizen science in pollinator monitoring: Current approaches, challenges and recommendations

The current decline in pollinator abundance and diversity poses a significant threat to the natural world and the food and economic security of human societies. A major challenge faced by the scientific community in pollinator conservation is the lack of sufficient data. Citizen science has emerged as a promising avenue for addressing this issue. In this article, we present the global perspective of citizen science projects focused on pollinator monitoring. Our analysis reveals a notable underrepresentation of developing and tropical countries in citizen science-driven data generation efforts. More than 70% of the listed studies are conducted in North America (n:64), followed by Europe (n:22). Together, Europe and North America account for 98.85% (n:86) of all the projects listed. Thirty-three percent of the projects are hosted on iNaturalist. Majority of projects focus on insects as pollinators, and 52% of the projects additionally document the identity of the pollinated plant species. We classified these projects into structured, semi-structured, and unstructured categories based on their methodologies. Linear regression analysis was performed to evaluate the influence of various factors on the potential for generating outputs. The regression model explained 82% of the variance in document production (Adjusted R-squared = 0.766, F(10, 33) = 15.06, p < 0.001). Structured projects significantly contributed to document output (Estimate = 12.44, p < 0.001), as did the inclusion of training (Estimate = 6.89, p < 0.001). Fisher's Exact Test for Count Data also revealed a significant association for outputs generated with the structured methodology (p < 0.001). Additionally, we discuss the merits and drawbacks of different approaches and propose recommendations for subsequent research.