Practice makes the expert: The importance of training volunteers in the generation of phenological data from photographs of biodiversity observation platforms

RESEARCH ARTICLE Practice makes the expert: The importance of training volunteers in the generation of phenological data from photographs of biodiversity observation platforms Julieta Salome´-Dı´az1,2☯, Jordan GolubovID3*, Omar Dı´az-SeguraID3‡, Ma. Cristina Ramı´rez-Gutie´ rrez4‡, Sarah Sifuentes de la Torre3‡, Patricia Koleff5☯, Esther Quintero5☯, Armando Jesu´ s Martı´nezID6 1 Instituto de Ecologı´a, Universidad Nacional Auto´ noma de Me´ xico, Ciudad Universitaria, Coyoaca´n, Ciudad de Me´xico, Me´ xico, 2 Posgrado en Ciencias Biolo´ gicas, Unidad de Posgrado, Edificio A, 1˚ Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoaca´ n, Distrito Federal, Me´ xico, 3 Laboratorio de Taxonomı´a y Sistema´ tica Vegetal, Universidad Auto´ noma Metropolitana, Coyoaca´ n, Ciudad de Me´xico, Me´ xico, 4 Facultad de Ciencias, Universidad Nacional Auto´noma de Me´ xico, Ciudad Universitaria, Coyoaca´ n, Ciudad de Me´xico, Me´ xico, 5 Comisio´ n Nacional para el Conocimiento y Uso de la Biodiversidad, Tlalpan, Ciudad de Me´xico, Mexico, 6 Instituto de Neuroetologı´a, Universidad Veracruzana, Dr. Luis Castelazo s/n, Col. Industrial Animas, Xalapa, Veracruz, Me´xico ☯ These authors contributed equally to this work. ‡ These authors also contributed equally to this work. * gfjordan@correo.xoc.uam.mx Abstract Phenology studies the time at which events in the life cycle of a species occur sand how they are related to environmental cues. Patterns of change in phenology at different scales can be used as an indicator of ecosystem changes and climate change, but the data neces-

sary to detect these changes can be difficult to obtain due to their temporal and regional dimensions. Citizen science can contribute to generate large amounts of data on phenologi- cal changes at wide geographical scales that would be almost impossible for professional scientists to generate, but the quality and reliability of these data are often questioned. The objective of this study was to evaluate the use of a biodiversity observation citizen science platform based on photographic information as a potential source of large-scale phenologi- cal information, and to identify the key benefits and limitations of this type of information source. We used the Naturalista photographic databases for two invasive species in a tropi- cal region: Leonotis nepetifolia and Nicotiana glauca. The photographs were classified into different phenophases (initial growth, immature flower, mature flower, dry fruit) by three groups of volunteers: a group of experts, a trained group with information on the biology and phenology of both species, and an untrained group. The degree of reliability of the phenolog- ical classifications was estimated for each group of volunteers and each phenophase. The degree of reliability of the phenological classification of the untrained group was generally very low for all phenophases. The group of trained volunteers showed accuracy levels for the reproductive phenophases that equaled the degree of reliability among the expert group, regardless of species, and was consistent across phenophases. We conclude that

volunteer classification of photographic information contained in biodiversity observation PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0282750 March 7, 2023 1 / 17 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Salome´-Dı´az J, Golubov J, Dı´az-Segura O, Ramı´rez-Gutie´rrez M.C, Sifuentes de la Torre S, Koleff P, et al. (2023) Practice makes the expert: The importance of training volunteers in the generation of phenological data from photographs of biodiversity observation platforms. PLoS ONE 18(3): e0282750. https://doi.org/10.1371/journal. pone.0282750 Editor: Jean-Franc¸ois Humbert, INRA/Sorbonne University, FRANCE Received: October 6, 2022 Accepted: February 22, 2023 Published: March 7, 2023 Copyright: © 2023 Salome´-Dı´az et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files. Funding: JSD was supported by the Posgrado en Ciencias Biolo´gicas (Universidad Nacional Auto´noma de Me´xico) and a Consejo Nacional de Ciencia y Tecnologı´a scholarship. GEF 00089333 project “Enhancing National Capacities to manage Invasive Alien Species (IAS) by implementing the