Interested in Using Museum Collections to Better Understand Freshwater Mussels? There’s Now an App for That

A new online resource combines data from 45 different natural history collections to provide easy-to-use information on America’s threatened freshwater mussels

Brown mussel shells sit in a white box with orange paper underneath.
The National Museum of Natural History’s Invertebrate Zoology collection contains around 24,000 freshwater mussel specimens, including shells of these endangered Snuffbox mussels from eastern North America. Jack Tamisiea, NMNH

These days, it seems like there is an app for everything. Mobile applications can be used for things as mundane as binging reruns and ordering groceries or as incredible as simulating an Apollo moon landing and bringing skeletal specimens to life. Even the Smithsonian’s resident Megalodon has its own app.

But few apps help researchers actively work together to save endangered species. To help fill this gap, John Pfeiffer, the curator of bivalves at the National Museum of Natural History, recently teamed up with Traci Dubose, a conservation biologist at Virginia Polytechnic Institute, and Sean Keogh, an evolutionary ecologist at the Field Museum of Natural History. The team’s goal was to create an easily accessible tool that provided researchers with the data necessary to track changes in freshwater mussel populations over time and space. This project yielded a new paper, published this week in the journal Biological Conservation, and MusselMapR, an web-based application containing more than 400,000 individual records of mussel specimens stored in museum collections across the country. 

While Pfeiffer thinks freshwater mussels “have all the rizz,” they are often overlooked in conservation circles in favor of more fluffy critters like pandas and polar bears. Freshwater mussels are deceptively colorful, long-lived and fascinatingly weird creatures that are one of the most threatened groups of animals on the planet. Nowhere is this decline more alarming than in the United States. In the last 100 years, more than 25 US mussel species have gone extinct. An additional 85 species are currently listed under the Endangered Species Act. Their decline is largely tied to habitat loss caused by damming and channelizing rivers.

The decline of these shelled invertebrates is disastrous for the entire freshwater ecosystem. A single mussel filters between 10 and 20 gallons of water per day as it feeds, keeping rivers clean. Providing this vital ecosystem service has led some to refer to freshwater mussels as the “livers of the river.”

Research Zoologist John Pfeiffer holds up a mussel specimen he’s collected in the field. His team’s new paper discovered that the amount of new mussel specimens being collected by researchers has dwindled in the past decade. John Pfeiffer, NMNH

To truly understand the timing, scope, and pattern of freshwater mussel decline, the best place to look isn’t a river. It is a museum collection, where mussel shells collected over decades, and even centuries, are safeguarded for scientific research. Tapping into this physical record helps researchers map how these species’ ranges have shifted and also determine how changing water conditions affect these filter feeders.

But all this data is only as useful as it is accessible. Most natural history collections are worlds unto themselves in terms of the ways and the types of information they record, making it extremely challenging to leverage their collective knowledge. 

When the COVID pandemic struck, Pfeiffer and other freshwater mussel researchers were prevented from accessing natural history collections in person. This forced him to reckon with the digital state of these collections. 

“Freshwater mussel collections data are often decentralized and nonstandard, which makes the information hard to access,” Pfeiffer said. “This project’s goal was to take all the chaotically formatted and decentralized data and put it into a single, easily accessible resource that would better suit the needs of folks trying to study and conserve freshwater mussels.”

One of Pfeiffer’s co-authors on the paper, Sean Keogh, sifts through mussel specimens stored in the collection of the Bell Museum of Natural History in Minnesota. Sean Keogh

Beginning in 2020, Pfeiffer and his co-authors reached out to 45 different freshwater mussel natural history collections across the U.S. to request they share their digitized collections. Once the team was able to wrangle all the data, they went to work  standardizing its format.

The researchers then compiled additional information as a means to complement the existing data. A key example of this was adding in information about the waterways from which the specimens were collected. “By using existing hydrological databases, we were able to enrich mussel collections data by adding information about the river’s size, volume, and speed, which is really useful in terms of describing habitat preferences,” Pfeiffer said. 

The final assembled dataset includes 410,665 individual records from 302 different species. This multitude of mussel specimens is searchable via the MusselMapR web application, which was designed by the researchers to help other biologists easily navigate such a sprawling collection of freshwater mussels.

Like other shelled mollusks, the inside of freshwater mussel shells are coated in a glimmering material called nacre, or mother of pearl. Jack Tamisiea, NMNH

With the database assembled and accessible, Pfeiffer and his co-authors set about analyzing it for patterns that might inform freshwater mussel conservation. The analysis revealed novel patterns and supported longstanding hypotheses. 

For example, one such hypothesis held that mussel species inhabiting large, now heavily-modified rivers like the Mississippi or the Ohio have disproportionately gone extinct or become endangered. The database revealed that this hypothesis was indeed supported by collections data — species listed under the Endangered Species Act tended to have a statistically significant preference for larger waterways with higher flow rates.

Traci DuBose, a co-author on the paper, collects water quality, sediment and mussel food data from Flint Rock River in Alabama. Erin Singer McCombs

The dataset also revealed another stark decline: the amount of new freshwater mussel specimens collected by researchers has plummeted by roughly 68% over the last decade. “Collecting freshwater mussels and depositing them in natural history museums is critical to measuring how mussel distribution and diversity has varied across time and space,” Pfeiffer said. “The recent failures to deposit specimens in natural history collections is likely to complicate future inferences about mussel diversity, distribution and decline.”

Like the at-risk organisms they study, mussel biologists like Pfeiffer face a number of obstacles in the future. Increasingly stringent regulations and limited funding are making collecting new specimens difficult. Because these challenges are likely to persist, having access to a database of mussel data is essential for maximizing collecting efforts.

These freshwater mussel specimens represent six different United States mussel species that were officially declared extinct in 2023. John Pfeiffer, NMNH

“Using these data we can make our collecting efforts more impactful,” Pfeiffer said. “Now we can more easily focus on species or watersheds that are poorly represented in natural history collections, which will help us increase the impact of the collecting we are able to do. It’s all about getting to a place where we can make data driven decisions about how to allocate limited time and resources for effective conservation.”

The early response to the database’s web portal has been encouraging. Various federal, state and non-profit organizations have spent more than 115 hours on the MusselMapR app in just the first three months since it went online. 

The team is excited to see the real-world applications of the U.S. database. “Freshwater ecosystems don’t get the same attention as their counterparts on land and in the oceans, but freshwater habitats are far more endangered,” Pfeiffer said. “Freshwater mussels are some of the most threatened animals in the most threatened ecosystems. This tool is designed to better understand these creatures and translate that into practical conservation.”

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