Tomomi Suwa

Does a partner in crime make it easier to invade?

Contributed by: Tomomi Suwa @tomommer



Asian-American, Bacteria, Community ecology, Ecology, Experimental, Field, Fundamental research, Immigrant, LGBTQIA+, Mother, Mutualism, Nationality, North America, Plants, Queer, Race/ethnicity, Restoration, Terrestrial, Woman



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Lau, J.A., T. Suwa. 2016. The changing nature of plant–microbe interactions during a biological invasion. Biological Invasions. 18:3527–3534. link

Data Nugget Activity:



Slide 1: Researcher’s Background

Tomomi is a data scientist at the Keller Science Action Center at the Field Museum (Chicago, IL). She helps create tools to make conservation more effective and inclusive.

PB: Why did you become a biologist?
TS: I always loved spending time outside in nature.

PB: What is your favorite part about your job?
TS: I get to work in the museum with very great people who care about the same things as I care about. Also, the Museum is a really fun place to work because there are so many cool things everywhere and I always get to learn new things!

PB: What obstacles have you overcome to get where you are?
TS: One of my biggest obstacles was/is language. Learning different subjects at school in English was hard, communicating with friends and teachers was hard. Sometimes, people didn’t/don’t take me seriously. But at one point, I needed to embrace myself and feel comfortable with who am.  As Rosita from Sesame Street once said (I recently watched this clip with my kids), being able to speak multiple languages is a “superpower”! 

PB: What advice do you have for aspiring biologists?
TS: Be true to yourself and be happy.

PB: Do you feel that any dimension of your identity is invisible or under-represented/marginalized in STEM?
TS: Yes

PB: Can you elaborate on your answer above?
TS: I don’t see very many LGBTQ Asian people, or LGBTQ people with kids in STEM


Slide 2: Research Overview

Take home message of study

Tomomi and her collaborator took soil samples containing rhizobia from three different sites with different histories of hairy vetch invasion: vetch had never been there (0 years), it arrived recently (< 3 years), and it invaded a long time ago (> 10 years). Next, they grew hairy vetch plants in each of the three soil types. After 8 weeks of growth, they counted the number of nodules on the roots (an estimate of how many rhizobia are growing with the plant) and plant biomass (how big the plants got). They found that hairy vetch grown in soil that was invaded recently or a long time ago had more root nodules and correspondingly higher biomass than soils collected from uninvaded sites. These findings suggest that mutualistic rhizobia may help the spread of invasive legumes by providing nutrients to them.

Study system

The top photo shows the invasive legume plant, hairy vetch (Vicia villosa), growing in the field. The bottom photo shows Rhizobia nodules on plant roots. Rhizobia live inside bumps on the roots of legumes, called nodules. There, they convert nitrogen from the air into a form that is usable by plants (ammonia); in return, plants provide the rhizobia with food and protection in the root nodule. Plants growing with rhizobia usually grow better than those growing without rhizobia.


Slide 3: Key Research Points

Main figure

The figure on the left shows the number of rhizobia nodules on hairy vetch roots (y-axis) that were grown in soil with no, new, or old invasion history (x-axis). The figure shows that hairy vetches had much higher numbers of root nodules when grown in soil with invasion history.

The figure on the right shows that hairy vetch grown in soil with new or old invasion history had higher total biomass (y-axis) compared to plants grown in soil with no invasion history. Interestingly, vetch benefited less when grown with soils from old invasion sites compared to recently invaded sites, potentially indicating that over a longer time scale, soil microbial communities change in ways that may reduce the success of plant invasion.


Societal Relevance

Invasive species are one of the biggest threats to biodiversity and the health of ecosystems. For example, a large proportion of threatened or endangered species are at risk due to invasive species. Invasive species also seriously impact human health and economies. However, why and how some species become invasive but not others is still not well understood. In our study, we showed one of the ways in which introduced species become successful in a new environment. We found that microbial mutualists can facilitate the process of legume invasion by providing nutrients to them. This information may not only be helpful to understand the process but also to slow down the future invasion of legume species.


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