Date November 21, 2017
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Brown’s Herbarium is a collection of ecology, geography and history

In the Brown University Herbarium, the digitization of tens of thousands of plants preserved over two centuries has opened the door to studies that span space, time and the diversity of nature.

PROVIDENCE, R.I. [Brown University] — Behind a zigzagging glass wall that faces into the main floor hallway of Brown’s BioMed Center, junior Dan Davis spent a recent Friday morning bringing precious treasures of natural history into the digital age. At the Brown University Herbarium, Davis — a dual concentrator in biology and music — has scanned thousands of pressed and dried plant samples into the facility’s rapidly growing public archive.

He places each sample in a brightly lit box that in another existence might house items being photographed for sale on eBay. A camera mounted above with the lens pointing downward snaps a perfect, high-resolution photo. As the image appears on a linked computer, Davis adds metadata to the database including whatever description appears on the label — what the plant is, where it was found, by whom and when.

The samples date back as far as the 1820s. Davis says he often reflects on the history of the eras he encounters.

“You’re handling plants that existed during Abraham Lincoln’s presidency and prior to the Civil War,” he said. “These are relics of that history. We have some that are from the first explorations of the Colorado River.”

Davis is not alone in such reflections. Two rooms deeper into the herbarium, senior Lance Gloss is hard at work, too. An urban studies concentrator, he thinks about the correlated human experience as he scans and studies the collection. Among many insights he’s gleaned in more than three years working in the four-year-old facility is that as American society transitioned from its agrarian past to its suburban present — with a clear turning point in the 1940s and ’50s — collectors of grasses shifted from a vocabulary of “pastures” to one of “lawns.”

A native of Fort Collins, Colorado, he’s currently contributing to a national study, funded by the National Science Foundation and led by the University of Colorado, focused on the ecological history of the southern Rocky Mountains. For instance, tracking patterns of plant diversity in the Rockies and tracing the advent and spread of invasive species. In encounters with early parts of that collection, he has seen aspects of the U.S. westward expansion.

“There’s are really interesting records of colonialism here and of the development of science,” Gloss said. “The territorial ambitions of the U.S. are really reflected here.”

In many ways, the Herbarium collection brings history not exactly to life, but to the life sciences. Collections manager Tim Whitfeld, an assistant research professor of ecology and evolutionary biology, says that now that the entire North American collection of more than 57,000 items has been digitized, the stage is set for a new generation of ecological studies. And with the help of a new cadre of students in Whitfeld’s plant collection and identification class every fall semester, the trove continues to grow.

Whitfeld isn’t sure precisely how big the collection is, but it could be as many as 90,000 samples. Davis is working on scanning in some of the 20,000 or so plant samples from the rest of the world. There are also more than 15,000 samples of fungi, algae, mosses and lichens.

Brown University botanists acquired the vast majority of the collection bit by bit over two centuries. In 2011, former faculty member Erika Edwards led an effort to move it from a cramped basement in the Arnold Lab to its new state-of-the-art facility in the BioMed Center with support from the Division of Biology and Medicine. Since then, Whitfeld, curatorial assistant Martha Cooper and about a score of undergraduates including Davis and Gloss have been organizing and digitizing it, with funding from the National Science Foundation, for the public good.

A fertile ground for science

The digitized plant samples are more than just interesting specimens, however — Whitfeld and his students have already begun to extract science from the plants. Last year with former student Sofia Rudin, for example, he co-authored a study tracking the history of heavy metal pollution in Providence.

“Sofia was working in the Herbarium doing digitizing and she noticed that certain specific localities in and around Providence — for instance, Mashapaug Pond on the West Side — were often mentioned on the specimen label of some early 20th century collections,” Whitfeld said. “She had the idea of what if we went back to these locations, collected the same species and did a comparison of lead and various other heavy metals. We showed that for some elements there wasn’t much change, but lead concentration has decreased.”  

There could be many more studies to come. Whitfeld aims to complete a comprehensive collection of all of Rhode Island’s estimated 1,700 current plant species. He and Assistant Professor Tyler Kartzinel, for example, have proposed a collaboration to study how New England’s plant diversity changes along environmental gradients such as elevation and interact with changes in the diversity of the communities of animals that depend on them.

More generally, what digitization brings is the ability to answer questions about ecology on a large scale. With the ease of developing online queries, researchers can cut across space, for instance to see how individuals of a species grow differently in different locations, or across time to see whether plants have begun flowering earlier as the climate has warmed (collectors tend to prize plants most when they are flowering).

“You could search the entire database for your species of interest and bring up all the images and look through them,” Whitfeld said.

That’s especially true given the collaborative nature of the Herbarium community. Brown’s collection is combined online with those of about 40 others across the region in the Consortium of Northeastern Herbaria. In all, the total digital collection tops 1.3 million records with some dating back to the 1700s.

And, of course, the physical specimens remain in place to provide vital data such as DNA and micro-scale morphology and anatomy. They are meticulously arranged and organized in cabinets that are carefully climate controlled. To walk among the stacks is to follow an evolutionary path that traces the plant tree of life in Rhode Island, North America and beyond.

Educational expeditions

Though the plants are all dead, the collection is living.

On the same November day that Gloss and Davis were busy in the lab, the class they each had taken in prior years, Rhode Island Flora, met in the afternoon one floor below. This semester’s crop of budding botanists was hard at work around lab benches. In groups of two or three, they scrutinized the samples they had collected earlier in the fall from forests and beaches across the Ocean State. Poring over the plants carefully pressed within pages of the Brown Daily Herald, the students sought to identify and make an informative label for each one. They looked through microscopes and matched leaf shapes and features to reference examples of plants online.

“The edges of the leaves, are they toothed?” a student gazing at a laptop asked his lab partner who stared at the specimen. The leaf edges were smooth, and so the search for a definitive ID continued.

In four years of the class, Whitfeld says, his students have added around 500 specimens to the collection.

Davis, who said his father is an amateur botanist who teaches him about plants in and around his hometown in Pennsylvania, took Whitfeld’s class last fall. He remembered it fondly as a chance to learn by doing work outside the classroom.

“It was wonderful,” Davis said. “Every week for the first five or six weeks we would go on field trips and go collecting. Tim would teach us the different environments and different types of forests and what proper pressing techniques are. We got to go to some really beautiful places.”

Though pressed, dried and stacked on cabinet shelves, the plants in Brown’s Herbarium can lead students on journeys through history, geography and from ecological unknowns to uniquely sourced scientific answers.