Elizabeth Wenk, Thomas Mesaglio , David Keith, Will Cornwell

Dynamic yet accurate reserve-level species lists are essential for conservation and biodiversity research. Even when such lists exist, changing taxonomy, ongoing species migrations and invasions, and new discoveries of historically overlooked species mean static lists can become rapidly outdated. Biodiversity databases such as the Global Biodiversity Information Facility, and citizen science platforms such as iNaturalist, offer rapidly accessible, georeferenced data, but their accuracy is rarely tested. Here we compare species lists generated for two of the world’s oldest, more famous natural reserves – Yosemite National Park in California, United States and Royal National Park in New South Wales, Australia – using both automated data extraction techniques and extensive manual curation steps. Here we show that automated list creation without manual curation offers inflated measures of species diversity at a reserve level. Lists generated from herbarium vouchers required far more curation than lists generated from iNaturalist, with both incorrect coordinates attached to vouchers and long-outdated names inflating voucher-based species lists. In comparison, iNaturalist data had relatively few errors, in part due to continual curation by a large community, including many botanical experts, and the frequent and automatic implementation of taxonomic updates. As such, iNaturalist will become an increasingly accurate source of automated biodiversity lists over time, but currently offers poor coverage of graminoid species and introduced species relative to showier, native taxa. At this point, researchers must manually curate lists extracted from herbarium vouchers or static reserve lists, and integrate these data with records from iNaturalist, to produce the most robust and taxonomically up-to-date reserve-level species lists.