Participatory citizen science data complements agency‐collected data for species inventories

Abstract Species inventories—comprehensive lists of all species in a given location—inform management decisions and conservation goals. In some instances, citizen science platforms may further contribute to species inventories, especially on public lands. Despite the growing availability of citizen science data, it is not known how these data compare to species inventories conducted by state agencies. We investigated how species inventories—across many taxonomic groups—conducted by a government agency (the Florida Department of Environmental Protection) for 39 state parks in Florida can be complemented by citizen science data generated from iNaturalist and eBird. We also investigated what, if any, characteristics of species and parks contribute to the difference in contributions made by citizen science. Across all parks, citizen science data recorded novel species in multiple taxonomic groups, with the largest contributions being insects and birds. However, the proportional contribution of citizen science data varied greatly by park, with a minimum of 2.9% and a maximum of 79.1% of species in each park detected only by citizen science. Most species in the examined state parks that had a designated conservation status from NatureServe were documented by agency data. However, citizen science sources did provide the only presence data of a small number of species of conservation concern (species with ‘Vulnerable’, ‘Imperiled’ and ‘Critically Imperiled’ statuses). Park characteristics, such as number of unique citizen science observers and observations, park acreage, population of the city in which the park is located and annual visitation, did not explain the over or under proportional sampling by citizen science data. Practical implication . Citizen science data can improve the completeness of taxonomically diverse species inventories by complementing data collected by government agencies. These data should be increasingly recognized for their value and curated in ongoing species inventory monitoring approaches.