ANHC botanist and Arkansas herbarium digitization coordinator, Diana Soteropoulos, co-authored a scientific paper published in the American Journal of Botany in November titled, “Small herbaria contribute unique biogeographic records to county, locality, and temporal scales.” Her co-authors began work on this paper in 2014, three years before Diana moved to Arkansas to start working on her doctoral degree at Arkansas State University (ASU) with her advisor, Travis Marsico, the lead author on the paper. Given her skills in data analysis, Marsico invited Diana to collaborate on the work and particularly assist with the statistical analyses.

The goal of this research was to demonstrate the importance of small herbaria to botanical and ecological research. Historically, researchers often had to physically travel to herbaria to examine and study specimens, so researchers selectively traveled to large herbaria to see more specimens. With ongoing digitization efforts to image herbarium specimens, transcribe the specimen label information into a standardized database, and assign GPS coordinates to specimens based on locality information (called georeferencing), herbaria of all sizes are now accessible online. How do scientists prioritize which collections to digitize first? And which herbaria should researchers search in online portals?

To explore the impact of herbarium size on unique information for research, co-authors from eight states – Arkansas, California, Colorado, Florida, Georgia, Michigan, Tennessee, and West Virginia – each selected 40 species from their state to examine. These species were split among four different status categories, with 10 species in each status:

1)S1 – extremely rare, typically representing fewer than five populations in the state.

2)S2 – very rare, typically representing six to 20 populations in the state.

3)Common native – a widespread, native species throughout the state.

4)Introduced – a non-native species.

Then, co-authors gathered herbarium specimen records for their state’s 40 selected species, verified the identification of the specimens, and georeferenced the specimen localities, if needed. The uniqueness of each specimen was then considered across three different scales: a county-level scale, a locality-level scale (using the GPS coordinates), and a temporal scale for when the specimen was collected. The number of unique contributions was analyzed by species status category and herbarium size, where small herbaria have fewer than 100,000 specimens and large herbaria have 100,000 or more specimens. Across all three scales (county, locality, and temporal), small herbaria contributed unique specimen data in proportion with the total specimens they contributed to the project and far greater than small herbarium holdings would suggest. Species status and herbarium size were important factors for large and small collections, so it is important to prioritize digitization and share data from herbaria of all sizes. Further, small herbaria had unique collections represented in the datasets; that is, they contain specimens that are not duplicated at large herbaria.

For Arkansas, 1,048 herbarium specimens from eight herbaria (seven small and one large) throughout the state were included in this research. The ANHC Herbarium (the third smallest herbarium in Arkansas at the time of the study) has nearly doubled in size since the data were collated for this paper in 2014. Nonetheless, the ANHC Herbarium contributed 73 specimens, greatly impacting the importance of small herbarium contributions for the state.

Unlike most herbaria in Arkansas, which have regional and general collection focuses such as the plants of Northeast Arkansas and the Mississippi Alluvial Plain at ASU or plants of Southeast Arkansas for the University of Arkansas-Monticello, part of the ANHC Herbarium’s mission is to house representative specimens from populations of rare plants throughout the state to complement the Arkansas Heritage Program’s database of rare species occurrences. As a collection specializing on rare plants, the ANHC herbarium contributed two of the 12 records in the S1 (extremely rare) status category and 31 of 89 records in the S2 (very rare) status category, or 33 percent of all the rare specimens analyzed for the state of Arkansas.

Of note, the ANHC contributed 11 of 15 records for harperella (Ptilimnium nodosum), a federally endangered wetland plant that grows along rivers and streams in the Interior Highlands, and the only specimen of leafy bulrush (Scirpus polyphyllus). This example illustrates what the study concluded -- small herbaria are important to research as they hold unique specimens not found elsewhere. The journal article advises that “While a thorough sampling of many herbaria is challenging in person, digitization offers an excellent compromise. We recommend including herbaria of all sizes equally in digitization efforts and encouraging the mobilization of digitized data and media to biodiversity data aggregators such as iDigBio (idigbio.org) and the Global Biodiversity Information Facility (gbif.org).”

If you’re interested in contributing to Arkansas’s herbarium digitization effort, check out the Plants of Arkansas project on Notes from Nature for transcribing herbarium specimen labels. You can also contact Diana Soteropoulos, [email protected], for a “how-to-transcribe guide” or to join the community of georeferencers finding historic herbarium specimen localities.