The Utility of Acoustic Citizen Science Data in Understanding Geographic Distributions of Morphologically Conserved Species: Frogs in the Litoria phyllochroa Species Group

Abstract.— Understanding species' geographic distributions is important for informing their conservation; however, an accurate understanding of where species occur is often precluded by a paucity of species records. For taxa that are difficult to visually distinguish at the species level, this problem can be compounded by misidentification of existing records. Citizen science has emerged as a potentially powerful tool to increase species observation data, but whether it can meaningfully add to our understanding of the distributions of species that are typically difficult to identify is contentious. We evaluated the volume, spread, and species identification accuracy of 3 yr of data from an acoustics-based citizen science dataset with a national aggregate of species observations collected over more than 140 yr (i.e., unvouchered human observations, photo-vouchered citizen science observations, and preserved specimens) to demonstrate the boundaries of five small, morphologically conserved frog species in eastern Australia. The national aggregate contained the most species records; however, the annual rate of record collection was much greater in the acoustic citizen science dataset. A high proportion of likely misidentified records were detected in the national aggregate dataset. Spatial bias differed between datasets, with acoustic citizen science data more biased toward highly populated areas. We demonstrate that citizen science can collect large volumes of spatially and taxonomically valid data which, especially when used in combination with more traditionally collected species records, can inform the detailed delineation of ranges in historically confusing groups of frog species.