Light and shade of citizen science for less charismatic invertebrate groups: quality assessment of iNaturalist nonmarine mollusc observations in central Italy

Abstract

Citizen science has grown in importance in recent years: many projects have been launched and records are being collected on an unprecedented scale. However, certain less charismatic invertebrate groups are still underreported and the accuracy and quality of their records in crowd-sourced citizen-science projects have rarely been investigated. Here, we used expert review to conduct quality control of nonmarine mollusc observations from central Italy on the online citizen-science platform iNaturalist (https://www.inaturalist.org/). As of December 2019, c. 400 observations of nonmarine molluscs had been reported from Tuscany on iNaturalist. Most records (59.4%) were identified to species level by the iNaturalist community and included a total of 90 taxa, providing interesting new chorological data of certain entities. Although identification of more than half the observations uploaded by the community was confirmed by expert malacologists, some major issues emerged: low quality of photographic vouchers; bias in favour of a few large common species; poor taxonomic knowledge producing incorrect identifications; and difficulty of identifying many taxa without anatomical study. Expert review remains an essential tool for verification and improvement of data quality in citizen-science projects. In this regard, information on the main diagnostic characters of the more common species (e.g. certain medium–large-sized snails and slugs) as well as tips on how to take good quality photographic images could be provided to volunteers in the form of simple guides and tutorials. High-quality training resources to support recorders and regular feedback and teamwork between scientists and citizens could prevent unverified or inaccurate records from impairing the accuracy of citizen-science datasets and offer a real opportunity to discover and conserve less charismatic taxa.

iNaturalist as a tool in the study of tropical molluscs

“…Taxonomic identifications on iNaturalist are recurrently problematic due to several factors ranging from the poor quality of photographs to the platform’s AI-based ID (identification) system [ 26 ]. Photographs are often awkwardly positioned, have low resolution, lack proper scaling, and do not highlight any diagnostic characters.…”

“…This seemingly democratic system is hampered by a few problems, such as users validating misidentifications suggested by the platform’s AI (which typically suggests European or North American taxa, even for observations in Brazil or elsewhere). As the system ranks users based on the number of IDs, “clickers”, i.e., users who want to accumulate as many IDs as possible regardless of whether they are correct or not, make the problem even worse [ 26 ], even though this has not happened frequently in the observations analysed herein. Furthermore, when a mistaken ID is extensively validated by users, correcting the error becomes nearly impossible.…”

“…To be usable in research, community science datasets need to be of high quality [ 21 ]. So, validation by experts is essential to ascertain the accuracy of the identifications and the benefits of the increasing engagement of scientists on the platform have already been pointed out [ 26 ]. In this context, Brazilian reality imposes some difficulties, starting with the small number of experts, who are often too overloaded with activities to be able to interact with the platform.…”

“…We revised the identifications of all observations on iNaturalist using current literature (e.g., [ 24 , 25 ]; and more specific taxonomic publications when necessary), as well as comparative specimens from the following natural history collections: CMRP (Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Ribeirão Preto, Brazil), MZSP (Museu de Zoologia da Universidade de São Paulo, São Paulo, Brazil), and NMNZ (Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand). By doing that, we avoid the issues of using the raw data from iNaturalist, as even those observations tagged by the platform as “Research Grade”—that is, dated and georeferenced observations of wild organisms that are identified to species level or lower by at least two-thirds of the identifiers—are sometimes incorrect [ 26 ] (see also the Discussion below). When the previous identifications on iNaturalist were found to be incorrect, they were updated via our user profiles (two of the authors, DCC and RBS, are Curators on iNaturalist).…”

“…However, the animals in many observations cannot be identified due to several reasons, including poor-quality photographs, awkward angles, and diagnostic characters not being visible [ 26 ] (see also Discussion below). In those cases, we have offered identifications to the best level possible, be it genus, family, or superfamily.…”