 The article presents a fuzzy model for evaluating the quality of volunteered geographic information, VGI, on species occurrences obtained by citizen science, CS, biodiversity monitoring programs, which assesses the trustworthiness of crowdsourced observations through three indicators of consistency with habitat, surroundings, and reputation of contributor. The proposed approach was applied to ASA macrofilm collected through eFlaura BC and iNaturalist CS projects and achieved high performance in detecting thematic and positional areas with a sensitivity of 0.99, specificity of 0.8, and Cohen's Kappa value of 0.79. This article was authored by Hosein Grahidi, Brian Klinkenberg, and Weinlin Yang.