Citizen scientists are important contributors to species distribution data

By Patrick Hanly

While citizen scientists are already known to be  a vital source of water quality data, they have also been quietly amassing a substantial collection of species records through digital platforms such as the popular iNaturalist. For example, there are 900,000 dragonfly and damselfly records on iNaturalist as of August 2020. Although iNaturalist was created with the goal of connecting people with nature, a fortunate byproduct of this effort is an extensive database of species records with spatial and temporal coverage that vastly exceeds the capacity of the scientific community.

Examples of some of my odonate observations recorded on iNaturalist in Ingham County, Michigan. Dragonflies (top): a blue dasher (Pachydiplax longipennis) on left and a widow skimmer (Libellula luctuosa) on right. Damselflies (bottom): an eastern forktail (Ischnura verticalis) on left and a double-striped bluet (Enallagma basidens) on right.

You may have heard of eBird, a well-established citizen science project run by the Cornell Lab of Ornithology that tracks observations of birds. Similarly, iNaturalist accounts for 66% of the U.S.’s 470,000+ georeferenced records in the Global Biodiversity Information Facility (GBIF), an international organization that focuses on compiling biodiversity data and making it publicly accessible. However, unlike eBird, iNaturalist encompasses all biota and relies primarily on photographic records that can be corroborated by the community. Corroboration is an important verification step that increases the quality of the data and allows researchers to be part of the identification process to fix errors prior to use. Observations can achieve “Research Grade” when they are properly dated and georeferenced, submitted with verifiable evidence, and when greater than two-thirds of users agree on identification.

I am developing tools to help people access these important data. All records (Research Grade or not) are freely accessible in an open database through the iNaturalist API. This online tool facilitates downloads into R using a package I am developing called iNatTools that provides data processing tools such as ways to determine sampling efforts for ecological research. Research Grade records are also exported to the biodiversity data compiler GBIF. To date, these GBIF records have generated 738 citations, showing that Research Grade iNaturalist records are an increasingly important source of contemporary distribution data for many taxa.

Georeferenced records of the blue dasher (Pachydiplax longipennis) on the Global Biodiversity Information Facility (GBIF) from iNaturalist (left) and from all other sources excluding iNaturalist (right). iNaturalist accounts for 22,781 of records since 2010 compared to just 203 from other sources.

Although vouchered specimens from museums and universities offer a wide breadth of species for many taxonomic groups, citizen science is an important source of recent and geographically widespread data for easily documented species such as dragonflies. These data will be essential for understanding biogeography and other investigations into species and ecological communities. Despite the large and growing number of observations, the biodiversity of many areas remains poorly documented. You can help fill these gaps — get started as an observer, identifier, or both.

Number of iNaturalist species observations within 500 meters of all Michigan LAGOS-NE lakes > 4 hectares. As of July 2020, 10,710 of the 15,569 lakes lack observations entirely for any taxonomic groups.



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