World Rainforest Day: A Conversation with Tropical Ecologist Jess Zimmerman

Jess Zimmerman is a tropical ecologist working as a professor at the University of Puerto Rico and acting as the current director of the Luquillo Long-Term Ecological Research (LTER) Project. In honor of World Rainforest Day, Cat McGee sat down with Jess to talk about his work and the importance of celebrating this day.

Cat: Can you tell me a bit about what you do and the research you conduct?

Jess: My long-term interest in plants has always been gender. I developed this fascination early on, and some of my first publications were in plants that have separate male and female individuals. Most plants are hermaphrodites, that is male and females. Pollen and seeds are produced by the same individuals. And I discovered while I was a graduate student starting at the University of Utah that there was this group of orchids that changed sex. There was evidence that it was an environmentally determined sex change, which is a fascinating topic. I discovered there were opportunities in Panama not only to study one of these orchids, but also to obtain funding from the Smithsonian Tropical Research Institute. I fell into tropical biology almost by accident. My interest in gender and plants sent me down to these orchids. And then it just happened that there were opportunities in Panama. I did all my research in Panama while I was at Utah. I graduated, did a postdoctoral with the Smithsonian Institute in Maryland, again on orchids. And then was hired in 1991 by one of my predecessors, Bob Wade, to help run the El Verde Field Station in Puerto Rico and to run a project on forest productivity. I kind of switched gears and rather studying than the things that grow on trees, I started studying the trees themselves. But again, the questions were quite similar because the issues of gender fall into a larger class of questions related to life-history variation, which is the various tactics and strategies that plants and animals use to contend with the variable environment. Questions about how long to live, whether to breed once or many times. Fundamental questions in ecology all revolve around these sorts of questions. I was trained as a population biologist, but then I fell into working with the Luquillo Forest Dynamics Plot, which is community ecology, but communities of organisms are simply the dynamics of individual populations played out as a group. I was able to make the leap from population community ecology without much effort. I’ve spent a lot of time working in LTER since those early days, as well as working with the Luquillo Forest Dynamics Plot in a life-history context.

Cat: What led you to this career?

Jess: My dad taught at the medical school at the University of Iowa and three of his colleagues and him bought this timberland outside Iowa City. Our Sundays were spent on this property learning the identification of all the wildflowers, learning the birds, he was sort of an Aldo Leopold outdoorsman. We had a cabin out in this property that we spent quite a bit of time with. Growing up there was squirrel hunting, duck hunting, and pheasant hunting. Then all the game cooking that went along with that. I took what was a series of hobbies for my father and converted it into a career. And that’s one of the things that distinguishes a lot of biologists, they’re just so tickled that they can actually get paid to do their hobby. I’ve always been fascinated with biology and complexity. I’ve always been about the ideas that drive evolution, population and community dynamics, coming at it more from a theoretical perspective. The ideas that tie everything together.

Cat: Why is Rainforest Day is so important to celebrate and how it connects to the work that you do with Luquillo?

Jess: There seems to be so many days and months celebrating things, and we do this because they’re overlooked or have special and unique properties. The Luquillo LTER is devoted to understanding the El Yunque rainforests, a cultural icon in Puerto Rico. We’re directly concerned with what’s going to happen to this rainforest if the rains cease, if the hurricanes increase. Climate change not only changes the temperature and the precipitation, but also it changes the disturbance regimes which is how often we have storms like hurricanes. So as a culture icon, El Yunque represents to the greatest extent what Rainforest Day is all about.

Cat: Since you began your career have you seen more of an emphasis towards inviting young people to understand the importance of sustainability and respecting the environment, opening doors for them to see this as a career for themselves?

Jess Zimmerman with Luquillo LTER Schoolyard students

Jess: Yeah, in growing ways. There’s a group called the Organization for Tropical Studies that began in the 1960s. It was a bunch of ecologists, tropical biologists that worked in Costa Rica to promote education and research. They used to run a bunch of courses for graduate students. That was an elemental part of many people’s upbringing as tropical biologists. They’ve struggled in recent years to fill those courses. That’s in part because we’ve done such a good job of bringing younger and younger people into understanding and doing research on rainforests.

Most undergraduates who are interested in research do what’s called an REU or research experience for undergraduates, usually between their junior and senior years. That introduces them to the process of scientific inquiry, fieldwork, and methods of whatever they may be studying. One of my colleagues, Ariel Lugo, said to me, when you go to conferences, you’ll see graduate students going around the meeting, followed by a trail of undergraduates. You never saw that in my day when I was a graduate student. Now we have a program called Schoolyard LTER in our LTER program where we try and bring in high school students, K-12 students, and expose them to the idea that they could be a scientist themselves. The idea is that we develop people early on. Most people have a fascination with biological entities. It’s kind of an innate thing that most young children have and should have the opportunity to develop. The thing is to tap into that and to stymie the forces that say because you’re a woman, or because you’re a person of color, you can only pursue certain careers. They can do this. We demystify the process. Most of us never paid to go to graduate school. You can do this without breaking the bank or racking up a lot of debt. In fact, I encourage my students to avoid incurring great debt, because they shouldn’t have to in order to pursue a career.

Cat:  Can you elaborate more on the LTER Schoolyard program?

Jess: It began in 1997 when Bruce Hayden was the Division Director of the Division of Environmental Biology. And he just changed the budget so that every LTER program had a small amount of money to do outreach to K-12. It’s an important legacy. We tapped into the fact that for a number of years up before then, going back to the early ’80s, a handful of teachers had taken a course on ecology of Puerto Rico from Ariel Lugo, who worked for Forest Service. We put our resources into the forest schools he was working with. At that time, we were trying to help them establish secondary forest plots near their schools that students would measure over time, so that they could look at long-term research. We tried to support them in that endeavor. We’ve changed the strategy over the years to try and involve more teachers, more students at more schools, particularly schools around El Yunque. We’ve evolved into a data jam mode, which makes direct use of the resources of the LTER, which are long-term data sets like stream flow, precipitation, and temperature. We teach them how to ask questions of the data, how to make graphics, and how to make presentations from those graphics. They learn the value of long-term data, and they learn environmental lessons connected to the rainforests. Then at the end of the year, we do a simple joint symposium with one of the other LTER sites, Sevieta in New Mexico, completely done in Spanish on both sides. Students get the opportunity to take a project and go full circle. That’s with less emphasis on collecting the data, which is what we used to do before, and more on making use of the data to answer a research question.

LUQ-LTER Schoolyard logo
LUQ-LTER Schoolyard students on site in el Yunque

Cat: What has been the most surprising discovery that you’ve made when it comes to your career as a researcher?

Jess: For us in Puerto Rico, the system is more resilient than you can imagine. There were papers written in the 1960s talking about rainforests or tropical forests as being nonrenewable resources, something that was damaged once, and you couldn’t get it back. Certainly, when humans make large scale deforestation, it’s hard for the forest to recover if there’s no remnants. But even in the mainland context, they’ve discovered that left alone, forests will come back on their own in a process we call secondary succession. We live in a system that sees lots of landslides and experiences hurricanes every 10-30 years. The disturbance regime is part of the ecology of the place. Most rainforests have some kind of disturbance regime, even if it’s just isolated tree falls from thunderstorms. In the forests, there’s a self-organization principle that causes them to regrow and you see that in great action in Puerto Rico. We recently wrote a review in Biological Conservation, where we talked about all the changes that the rainforests in Puerto Rico have seen and how it has recovered, even massive deforestation of the lower elevations. It’s now completely covered in forests. Part of that was due to the efforts of Forest Service at the time, replanting the forest, but a lot of it is just due to the natural processes of succession. Forests seem to have these characteristics of resiliency. The question for us going forward is, does climate change challenge that? It can be very worrisome when you’re looking at a potential 50% reduction, and what was once a rainforest is no longer a rainforest. Or a four- to eight-degree increase in temperature, taking them into temperature ranges that those organisms have never experienced, even evolutionarily for 50 million years. It’s resilient, but there’s always a nagging worry that we’re going to reach some tipping point where the organisms become challenged and the system changes in ways that fundamentally alter its structure or function.

Cat: Are there things that people can think about doing that make a good contribution to counteract that worry and help preserve our planet and its forests?

Jess: Go to zero carbon emissions is the best way to do that. Thinking about where your everyday carbon emissions come from is one way to do that. I recently bought a hybrid car because I travel a lot to work. Working from home is one solution. Simply eating less meat is an obvious way to do that. Chicken has less impact than cattle because of cattle’s unique physiology as ungulates, as they consume grass and processes food, they produce lots of methane, which is a greenhouse gas unto itself that converts in the atmosphere to CO2 that has a long residence time. That’s bad for cattle producers, but maybe they should be doing something else. We used to live by horse and buggy but what did the horse and buggy people do when we stopped using horses? They found alternative ways of employment. Change is a constant. And insisting on living like we did 50 years ago is not a solution. It goes back to that thing they said in the ’90s, think globally and act locally. And there’s lots of tools on the web that will show you where your carbon is coming from. Unfortunately, a lot of it has to do with plane travel, which is a huge source for most individuals. It creates a conundrum for those of us who like to travel. But if you travel, you can donate money to companies like World Land Trust, Rainforest Concern, and Climate Stewards that are doing something on the ground to plant more trees to absorb that carbon. You can mitigate your carbon as an individual by helping in small ways.

Cat: What kinds of things do you identify in young people that make for a good investigator?

Jess: There’s a thing called grit that I’ve learned about working with Steven and other education researchers and educational psychologists. Some people just have stick-to-it-iveness that they don’t take “No” for an answer. If there’s a problem, they view themselves as part of the solution, not other people. There’s just an attitude about getting things done that carries people to a research career or any career.