ETSU Biologist Co-Authors Study On Pollinators' Role In Plant Diversity Published In Journal

From East Tennessee State University:

September 9, 2021

JOHNSON CITY – East Tennessee State University’s Dr. Gerardo Arceo-Gomez is a co-author of a study published Sept. 8 in the journal Nature examining the role of pollinators in the maintenance of diversity among flowering plants.

Arceo-Gomez was part of a team led by Dr. Na Wei of the Holden Arboretum in Kirtland, Ohio, and Dr. Tia-Lynn Ashman of the University of Pittsburgh that conducted a National Science Foundation-funded study of a plant-pollinator system in the serpentine seep communities in northern California, which is a global biodiversity hotspot.

“How rare species are able to persist in any given environment has been a long-standing question in ecology and a key question for understanding the mechanisms that help maintain biodiversity,” Arceo-Gomez said. “This topic is of particularly great importance given the current environmental challenges that threaten the persistence of many species, especially those that are less abundant.

“Although there is plenty of support for the role that plant-pollinator interactions have played in giving rise to the diversity of plants we see today, their role in the maintenance of such diversity is less understood. Particularly, it is not well known how plant-pollinator interactions may help rare species persist in the presence of more abundant ones.”

The researchers evaluated the roles of three mechanisms that may favor the persistence of rare species. These included pollinator specialization, or niche partitioning; pollinator facilitation among co-flowering species; and plant reproductive self-sufficiency, or auto-fertility.

The information the scientists used to test predictions associated with these mechanisms consisted of data on 7,324 pollinators collected over two years. These pollinators representing 416 species – most of which were bees – visited 79 co-flowering plant species.

In sampling over 3,500 plant styles, the scientists counted 3.1 million pollen grains deposited on the plant stigmas. This allowed them to track plant success from both male and female perspectives, which Arceo-Gomez says has rarely been evaluated together in whole-community studies of this scale.

“One of our major findings,” Arceo-Gomez said, “was the high degree of pollinator specialization in this system. But more importantly, we found that rare species were more specialized, and this led to their higher reproductive success compared to their more abundant counterparts. This suggests an important role of niche differentiation, or pollinator specialization, in the maintenance of rare species.

“However, when rare species did share pollinators with other plants, they tended to benefit from a joint pollinator attraction in detriment of their abundant co-flowering neighbors, suggesting that facilitation exists, but it is asymmetric. That is, only rare species benefited from sharing pollinators while abundant species were affected by it.”

Arceo-Gomez, who collected data and samples in the field for the study prior to the COVID-19 pandemic, explained that these are the first findings to show strong support for predictions that pollinator specialization and asymmetric facilitation favor the persistence of rare species in highly diverse co-flowering communities, and therefore contribute to the maintenance of overall plant diversity.

“We emphasize that the role of plant-pollinator interactions in the maintenance of plant diversity is of great importance, and that the overall functioning of communities – the identity and efficiency of specific interactions – and not just the sole presence of plants and pollinators, should be preserved,” he said.

To read the article, visit nature.com/articles/s41586-021-03890-9.

To learn more about the ETSU Department of Biological Sciences, visit etsu.edu/cas/biology/.

This press release was produced by East Tennessee State University. The views expressed are the author's own.