This year, our lab formed an Anti-Racism Discussion Group and read a series of books to broaden our perspective on diversity, equity, and inclusion. We met monthly for discussions, and learned a lot from the books’ authors and from one another. If you’re interested in our reading list, we’ve listed each book (with a few words about its contents) below. We’re also happy to share our discussion prompts and more detailed thoughts on request.

Summer 2020 — Black Faces, White Spaces by Carolyn Finney
We chose this book as our summer book club reading, and found it to be an illuminating discussion of a number of issues surrounding the intersection of the Black experience and the American outdoor/environmental movement. This book had a different writing style from our normal scientific (or popular science) fare, but we learned a great deal about the importance of who controls the narrative, how history impacts feelings of safety in nature, and the systematic exclusion of Black people from the American outdoors.

August 2020 — How To Be An Anti-Racist by Ibram X. Kendi (Discussion leaders: Laura, Alexandra, and Ferdinand)
We kicked off our anti-racism reading group with this important and insightful text. Kendi’s work is widely read (and widely recommended) for a reason: His self-examination throughout the narrative helped his message resonate with each of us as we evaluated our own actions and asked how we could become more actively anti-racist. Among the points that resonated with us were Kendi’s explanation of the origins of race as a social construct, his metaphor of water flowing into buckets at different rates for the legacy of inequity caused by institutionalized racism, and his description of the vital importance of Black communities.

September 2020 — Biased: Uncovering the Hidden Prejudice that Shapes What We See, Think and Do by Jennifer L. Eberhardt (Discussion leaders: Raine and Veronica)
Seeking deeper understanding of the implicit biases that can shape our actions and decisions, we turned to Biased to understand the social psychology of racism and other biases. While some of us felt the book could have been more critical of institutional racism, we found that the case studies Eberhardt used really resonated with us. We also appreciated the discussion of how shared experiences can break down implicit biases, but only under certain circumstances. 

October 2020 — Voter Suppression in US Elections, a transcript of a discussion between Stacey Abrams and others (Discussion leaders: Gabe and Michelle)
This was an incredibly timely choice given that the US election was right around the corner when we held our discussion. (We applaud the members of our lab who phone- and text-banked to encourage voter turnout around the country!) Yet it was also a painful and frustrating read because it highlighted the really blatant ways in which government policy has been used to suppress Black voters in particular. The first half of the book is a transcript of a panel discussion on the topic: Although some of us needed to adjust to this different style of text, the personalized nature of the conversation and details shared really helped bring the message home. The book ends with a compilation of relevant articles that add context to the transcribed discussion.

November 2020 — The Color of Law: A Forgotten History of How Our Government Segregated America by Richard Rothstein (Discussion leaders: Holly, Laura, and Ean)
Our previous readings had highlighted the ways that racism is “baked in” to US policy, so we chose The Color of Law to learn more about this history. Rothstein’s thesis is that America’s current segregated state is not simply the consequence of individual (racist) choices, but rather is the outcome of systematic policy at both national and local levels. He draws on examples from across the US, including the SF Bay Area and New Jersey, hitting close to home for many of us. This was a good November read as it provided excellent fodder for Thanksgiving discussions with family members about the deep legacy these policies have left, including segregated neighborhoods and enormous wealth gaps.

December 2020 — American Islamophobia: Understanding the Roots and Rise of Fear by Khaled A. Beydoun (Discussion leaders: Chris and Ferdinand)
This year we prioritized learning about the Black experience, but we also recognized parallels in the inequities and biases faced by other races and religions. So, we ended the year by reading about Islamophobia in the USA. Many of us found this book more difficult to read than our previous choices, and asked ourselves whether this was shaped by our own unconscious biases. We learned a lot from the book’s description of the long history of Islamophobia in the US, including the post-Cold War political interest in casting Islam as a civilizational opponent (“clash of civilizations”), and the role some academics played in that. While we felt that the author’s language and examples could have been more nuanced, we recognized the divergence between fear of (and government policies to stop) religious-based terrorism, and the far greater threat of home-grown (e.g., white supremacist) terrorism in the United States.

An addendum from Holly: Overall, this year’s reading provided me with lots of opportunities for learning and growth. I’m grateful to our lab group for participating in this learning experience, especially the discussion leaders who provided weekly reminders of the reading schedule and crafted thoughtful discussion prompts for our monthly meetings. Some things that I think worked well:

1. Choice of reading material — Among the books we read, I would especially recommend How to be an Anti-Racist as an entry point to the subject matter and The Color of Law as an excellent summary of racist (to use Kendi’s, and our, definition) legal policies in US history.
2. Paired discussion leadership — Rachel Germain told me about an equity discussion group (BREWS at the University of Toronto), and emphasized the importance of paired discussion leaders. We found that working in teams was a good way to not just share the work of organizing the month’s discussion, but also feel supported and have a “gut check” when dealing with sensitive topics.
3. Use of small-group discussions — We spent most of our hour-long Zoom meetings in small (3-4 person) breakout rooms, discussing prompts from the discussion leaders and taking notes on a Google Doc shared across all groups. At the end of the hour, we’d return to the large (10-15 person) group to debrief. As all classroom instructors know, this provided a more intimate setting where everyone’s voice could be heard, as well as integration at the end to highlight the various topics each group discussed.
4. Defraying costs and emphasizing that participation is voluntary — There are lots of barriers for entry in our community: We didn’t want money to prevent participation here. We set up a small lab fund (via Visa gift card) that people could use anonymously to purchase copies of each month’s book (and often found free copies through UCSB’s library system). And because the subject matter resonates with each of us in different ways, we didn’t mandate participation, and took care to be respectful of one another in discussion.

“Give me an example of how your training in mathematics led you in a new or surprising direction as a biologist,” said Mike. (As part of my preparation for job interviews, Mike has been inserting questions and prompts like these into our conversations at random. He takes his advising role very seriously!)

“Well, once upon a time in a far off land where the ocean is too cold to swim in,” I began (it was late September on Cape Cod, and the water was still luxuriously warm), “I was thinking a lot about how trees invest in their fungal partners.”

I was in my first year of Ph.D. work at Stanford when inspiration struck. My thesis was starting to take shape: I’d be studying the processes that maintained diversity in ectomycorrhizal fungi, the belowground partners that help trees gather nutrients and water from the soil. The host trees obviously play a major role: it’s their “payments” (in terms of carbon food) that support those fungi. How much the trees invested, in whom, and when, were — and largely remain — open and important questions.

Just a year before, I’d been working with Mike on a masters thesis that used a branch of mathematics called “optimal control theory.” This is the kind of math we turn to when we want to answer questions like, “How should I invest my fixed amount of money to control the spread of a disease?” (We’d been using it to ask “How should I distribute my fishing fleet to catch the most fish?”)

With partial differential equations and Hamiltonians and greek letters dancing in my head, I thought: “Why can’t we use the same tools to understand tree investments?” Basically, we just need to adopt the tree’s perspective to ask the question, “How should I pay my fungal partners so that I wind up having grown the most at the end of the day?” Taking a traditionally bioeconomic tool, and applying it to a purely biological system, made perfect sense to me — but was also a new approach.

And so, the idea for a new paper, out this month in The American Naturalist, was born.

The road from inspiration, in 2011, to publication, in 2016, has been long, inventive, and exciting. The paper we published is not really the one I intended to write. Instead, it describes an unexpected finding — which makes me very happy, because, like my coauthor Mike Neubert, I believe that mathematical models are most  valuable when they surprise us. We’ve also had a lot of support along the way — from interested colleagues to my thesis committee members to the journal’s very enthusiastic editorial staff.

And, five years later, I have to say: I’m really proud of this one.

The official press release is online here; since we wrote it, I’ve also included it below.

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Sometimes, even low-quality partners are worth maintaining

A fruiting body of the ectomycorrhizal fungus Amanita muscaria pokes through a carpet of pine needles shed by its mutualistic partners. A. muscaria coexists on tree root systems with dozens of other ectomycorrhizal fungal species. Photographed in Cora Lynn, New Zealand, by H. V. Moeller (January 2012).

A major challenge of ecology is explaining species diversity in natural communities. For example, why do some species interactions—like the mutualistic relationship between plants and the below-ground fungi that help them gather nutrients from the soil—involve dozens of partners, especially when some of those partners don’t pull their weight in the relationship? Although such ‘low-quality’ partners die quicker, grow more slowly, and/or move nutrients less efficiently, they still remain part of the mutualistic community

In a recent paper, mathematical ecologists Holly Moeller and Michael Neubert of the Woods Hole Oceanographic Institution present a new explanation for the persistence of low-quality community members: They may be actively maintained by their partners as part of an “optimum” investment strategy designed to maximize their partner’s growth.

Using a mathematical model of the exchange of carbon and nutrients by trees and fungi, Moeller and Neubert show that a tree’s investment in its fungal partners depends on environmental conditions. In their model, trees invest only in high-quality fungal partners when the environment is constant, but, when the environment is variable (e.g., if nutrient supply fluctuates over time), trees may also nurture low-quality partners to meet their nutrient demand. Because long-lived organisms like trees and fungi are almost certain to experience environmental variation during their lifetimes, such active partner investment may be an important mechanism that maintains species diversity.

Find our article, at last “officially” published online, on the journal’s website. I’ve also posted a PDF here.

“Homogocene.”

That’s the term some of my scientist colleagues are using for the current ecological epoch, during which humans have moved different species all around the planet.

We can’t help it. We move some of these species deliberately — because they’re key crops, because they make good companions, or because they remind us of home. We move some accidentally, when they tag along on airplanes or boats.

Unfortunately, our global exchange program has had some nasty side effects. Introduced species can become invasive, in some cases taking over landscapes and displacing native species. Certain places, like island ecosystems whose delicate balance has evolved in isolation for millennia, are especially vulnerable.

New Zealand is one such place.

Today, numerous North American tree species, originally brought to the country by foresters seeking the ideal species for their timber industry, are invading across both North and South islands. Douglas-fir (Pseudotsuga menziesii), the giant of the Pacific Northwest, is one such tree.

In a new study published this month in the journal Ecology, my Ph.D. advisor and I worked with collaborators in New Zealand to understand the belowground community at the Douglas-fir invasion front. We were particularly interested in a group of fungi called ectomycorrhizae: These mushroom-formers travel through the soil collecting nutrients and water, which they then deliver to their host trees in exchange for sugars (carbon that the tree fixes through photosynthesis). Without these mutualistic fungi, Douglas-fir (and other invasive pines) can’t grow and expand their range. So identifying the types of fungi that are available is one way to figure out why Douglas-fir is becoming invasive.

We show that Douglas-fir’s complement of fungi is context-dependent: That is, where you are matters. In Douglas-fir plantations, invading seedlings can find lots of familiar faces, fungi that were brought to New Zealand (either deliberately or accidentally) from Douglas-fir’s home range in North America and therefore make ideal partners. Outside plantations, community composition is more variable — and might explain why Douglas-fir can invade in some places, and not others. Troublingly, however, the Douglas-fir invasion into native forests doesn’t seem to be fungus-limited, possibly because Douglas-fir, apparently uniquely among invasive trees around the world, can form associations with native New Zealand fungi.

Read more at the journal’s website.

Download the pdf.

In today’s fast-paced, increasingly crowded world, we often view our conservation goals as directly in conflict with our economic ones. Save a forest, or cut it down for lumber? Preserve a wetland, or drain it for human habitation?

Marine reserves, parts of the ocean where commercial fishing is prohibited, are usually seen as embodying that conflict. On the one hand, they provide great conservation benefits by acting as safe zones for overfished species. On the other hand, they remove a portion of the fish stock from harvest and, in so doing, seem to remove money from fishermen’s pockets.

Fortunately, a growing body of literature is showing that marine reserves may be part of an economic best-case management strategy. That is, sometimes, you want to protect a portion of your fish stock, so that you can make more money when you fish the rest.

In a new paper out this month in Natural Resource Modeling, Mike Neubert and I highlight the economic benefits of marine reserves when fishing damages habitat. There are many cases in which habitat damage occurs: here on Cape Cod, the long history of bottom trawling for cod and haddock is just one example.

Using a very simple model in which we divide habitat into two portions, we show that profits are maximized when one of those two portions is closed to fishing. The reason for this is that the closed “patch” provides undamaged habitat that houses a healthy fish stock. The spillover from that patch (i.e., the fish that leave the reserve and swim into the fished habitat) can then be caught and brought to market.

For more information, contact Mike or me. You can also read the full paper online. [Access via journal website] [pdf]

Want to know even more? Check out our 2013 paper, which uses a more complicated model (partial differential equations to model continuous space) to show the emergence of marine reserve networks protecting >80% of habitat as part of the economically optimal management strategy. [pdf]