Can citizen science fill knowledge gaps for the world's most speciose and poorly-known insular amphibian fauna?

Abstract

Context: Tropical regions host the richest, yet most poorly known and threatened concentrations of biodiversity on the planet. Citizen science is increasingly viewed as a strategy to help fill these key data gaps. However, inadequate taxonomic frameworks, social inequities, and poor infrastructure may all constrain this potential. Aims: To examine how effectively citizen science data from iNaturalist fills gaps in knowledge about the distribution, species richness and conservation status of a megadiverse tropical biota, namely the frogs of Melanesia (New Guinea and nearby islands). Methods: We identified all records of Melanesian frogs on iNaturalist to species or genus where possible. Species distributions on iNaturalist were then compared to existing distribution maps and records to identify range extensions, and the IUCN Red List conservation status of any species not currently considered Least Concern was assessed based on new distributional information. Key results: We estimate that around 125 described Melanesian frog species (23% of the total fauna) have been recorded on iNaturalist, including putative range extensions for at least 42 species. Based on these new data we recommend updating IUCN Red List assessments for nearly 20 previously Not Evaluated, Data Deficient, or Vulnerable species. Many records cannot be identified to species, and this issue is compounded by a mismatch between the area best-known scientifically (Papua New Guinea) and the area from which the majority of citizen science records originate (Indonesia). Conclusions: Citizen science has clear potential to fill some key knowledge gaps for poorly-known tropical biotas, but does not obviate the need for baseline survey and taxonomic work based on voucher specimens with associated tissues. Implications: Based on our experience, we make recommendations that may increase the impact of citizen science data for poorly-known biotas.