While research is an intrinsic mission for most herbaria, it is not usually seen as a form of outreach, but I would argue that in some cases it definitely can be. In this post in my series on outreach (1,2), I’d like to present two recently published papers based on herbarium specimens that are scientifically interesting and fascinating enough to intrigue the general public. The first is on seeds brought in with ballast on ships during the 19th century and comes from the Chrysler Herbarium (CHRB) at Rutgers, the State University of New Jersey (Schmidt et al., 2023). The lead author Ryan Schmidt was a curatorial assistant there while completing his undergraduate and early graduate studies; he has now moved on to a Ph.D. program at Harvard University. The last author is Lena Struwe, a professor of plant biology at Rutgers and director of the herbarium. Struwe is the kind of dynamo who makes the herbarium world exciting. She is an active researcher, a well-known taxonomist, and a generator of student enthusiasm. She developed Botany Depot, “a global website for creative ideas and materials for teaching botany in the 21st century for all ages and levels.” It became a particularly important site during the covid pandemic. The other coauthors are Megan King, the herbarium manager, and Myla Aronson, a Rutgers professor who focuses on urban ecological studies. It definitely takes a team to produce an article like this, with Schmidt and Struwe designing the study and Schmidt collecting specimens and doing the analytics.
Schmidt took advantage of an area in which the Chrysler Herbarium is particularly strong, New Jersey plants, and asked what became of the many plants that came into the state via its ports at Jersey City and Camden (see map above). During the 19th century, ballast—usually sand, rocks, and soil—was used to balance sailing ships without enough cargo to keep them stable, a practice that ended by 1900 with the demise of wind-powered vessels. When the ships reached port they loaded their cargo after dumping the ballast on nearby land. Inevitably there were seeds in this material and many of them sprouted in and around the dumps. Some flourished, produced seed, and spread; others didn’t make it. Since these areas were active collecting sites in the 19th century, Schmidt was able to find over 200 species in the herbaria that were nonnative and that grew around Camden and Jersey City. He then followed what happened to these plants in the 20th and 21st centuries, doing a new survey of these areas in 202I-2022. He worked with over 8000 specimens in all and did a number of sophisticated statistical analyses on his results.
There is a great deal packed into this article, so all I can give is a brief summary of the results, but they are fascinating. Schmidt was able to divide the species into four groups. First were the “waifs,” making up 32% of the species; they grew and set seed but didn’t maintain stable populations and were only found as long at the ballast practice continued. The “short-term” species (20%) did hang on into the 20th century but disappeared rather quickly. The “established-limited spread” (30%) survived locally, mostly in the areas around the ports, while the “established-widespread” (18%) became broadly established and in some cases are now considered invasives. This study received media attention because it dealt with an important part of New Jersey’s history and also with the present problem of invasive species. This research was interesting even to people who didn’t know plant collections existed, so it not only contributed to ecological and botanical knowledge, but to bringing herbaria to the larger community.
A similar buzz surrounded a paper published by a team from the Botany Department (CM) at the Carnegie Museum of Natural History in Pittsburgh. The first author is Molly Ng, a postdoctoral fellow at the museum, while the next two authors, a professor Ryan Utz and a student Alyssa McCormick, are from Chatham University north of Pittsburg (Ng et al., 2023). The last author is another dynamic herbarium curator Mason Heberling who has a knack for investigating news-worthy topics. This case involves that odious plant Toxicodendron radicans, poison ivy. The research team used the herbarium’s historic collections along with freshly collected material to study the effects of elevated CO2 levels on leaf production, water-use efficiency, and toxicity, which had been shown experimentally to be elevated by increased CO2. However, field studies hadn’t found an increase in the abundance of poison ivy. Studies in many species have revealed decreased stomatal density with increased CO2, and it was true in the present one. Though leaf area increased, as would be expected from more robust growth, there was a decrease in water-use efficiency that may explain why the species growth overall didn’t change. I can’t go into more details here, but the punch line—that poison ivy growth isn’t being spurred by global warming—made the news, greeted eagerly by those of us used to things doing from bad to worse. Obviously more research is called for here, but again, it is always a plus when herbaria make it into the public consciousness and when the history of botany proves important to its future. In the next post, I’ll look at herbaria are reaching out beyond the bounds of their collections through social media.
References
Ng, M., McCormick, A., Utz, R. M., & Heberling, J. M. (2023). Herbarium specimens reveal century-long trait shifts in poison ivy due to anthropogenic CO2 emissions. American Journal of Botany, 110(9), e16225. https://doi.org/10.1002/ajb2.16225
Schmidt, R. J., King, M. R., Aronson, M. F. J., & Struwe, L. (2023). Hidden cargo: The impact of historical shipping trade on the recent-past and contemporary non-native flora of northeastern United States. American Journal of Botany, 110(9), e16224. https://doi.org/10.1002/ajb2.16224
Herbarium World 