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Thomas Lewinsohn

Thomas Lewinsohn: Amplitude to think

Ecologist integrates evolution and physical and mathematical models, and vaults over academic walls to influence conservation policy

028_Entrevista_LewinsohnLÉO RAMOSThomas Lewinsohn challenges the narrowness of a profile. In his research, he switches from fieldwork to physical and mathematical models, from scientific communication to conservation policy. He believes that it is not enough to develop theories without understanding how the organism behaves in the environment. Partnerships with specialists in several areas, of different nationalities, contribute to broadening the research topics he focuses on and how he approaches them.

He almost left biology while still an undergrad and considered switching to photography, but he discovered a comprehensive, evolutionary view of ecology that led him to pursue a master’s degree at the University of Campinas (Unicamp) in what was then the newly inaugurated program in Ecology, in 1976. He became a professor at the same university and, in 2016, 40 years later, is retiring before the compulsory age.

The decision, surprising even to him, was not because he was tired of science. He is not. He intends to change his relationship with work and continue to do research, advise students, and broaden his views, free of the administrative bureaucracy of academic life.

A month-long academic residence in 2014 at the Bellagio Center of the Rockefeller Foundation, in Italy, allowed him to work with thinkers and artists from different countries and areas in a stunning landscape, with medieval ruins and Renaissance buildings. It was an ideal setting for broadening horizons and proposing a way to share information about biodiversity and create manageable units to guide students and politicians, avoiding the trend in using species with popular appeal. It is an experience that he intends to repeat in other places.

While continuing his work, he also spends time on photography and music. Born in Niterói, the son of German Jews who fled the Nazis, Lewinsohn is married to journalist Graça Caldas. They have two children and two grandchildren.

Undergraduate degree in biology from the Federal University of Rio de Janeiro (1975); master’s and doctoral degrees from the University of Campinas (1980 and 1988)
Academic production
80 articles, 6 books as author or editor, 16 book chapters, advised 16 master’s students (one in progress) and 12 doctoral students
(one in progress)

How did you end up at Unicamp?
I had problems during my undergraduate days at the Federal University of Rio de Janeiro, and withdrew during my third year, with the intention of not returning. I backpacked through South America and attended a conference on tropical ecology in Venezuela where I took a course taught by Otto Solbrig of Harvard University. I wanted to move there, but I returned to Rio because I was taking photos for textbooks and had met my wife, Graça. So my life changed. Back at UFRJ, I took a course that Woodruff Benson taught there. It was the first time I had seen someone in Brazil talk about the evolutionary biology topics I had seen in Venezuela. When he was hired to teach Ecology at Unicamp, I followed him.

What attracted you to evolutionary ecology?
Understanding how evolutionary processes are reflected in ecological structures. Shortly after I came here, I read a paper on the changing characteristics of a fruit called the courbaril in Puerto Rico, where a major seed predator was absent and the plant’s ecology — the morphology of the fruit, the beginning of reproduction — was completely different. It was an article published in Science magazine by Daniel Janzen, who was at the University of Michigan. He attributed the difference between Puerto Rico and the continent to the absence of seed predators. During the first fieldwork course we did in Amazonas, I saw another species of courbaril with drill marks and I began to look for seed predators. I opened a fruit and a wasp fell out. Janzen had never seen a parasite in 10 years in Costa Rica and claimed that it was impossible because the fruit was woody. I did my master’s degree on this courbaril system, working in different ecosystems — in the Cerrado savanna, in hard-ground forests, along the Tarumã River in the Amazon Forest.  I spent three years doing fieldwork.

Why did you then specialize in species of Asteraceae, the family of daisies and sunflowers?
I was looking for a cosmopolitan family with many species and different distributions, and Unicamp had two experts: Hermógenes Leitão Filho and João Semir. I wanted to learn about the richness of species of endemic plants compared to widely distributed ones. Part of this was the idea of beta diversity, which measures the differentiation between geographical locations or between plants harboring insect larvae. Few people were working on this, no one in tropical ecosystems, but I did not realize that I was opening a little-known field.

Now you revisit areas where you collected samples 20 years ago.
At that time we did a broad survey of all of the Asteraceae we could find. We traveled from the state of Rio Grande do Sul to northern Minas Gerais State, principally in the Southern mountains and the Espinhaço Mountains. We ran into the cruel reality of the tropics: most species are very rare. We obtained more than 600 species of plants. But for half of them we found only one specimen. Now we are looking for the same plants in the same places. I want to see how the interactions are differentiated geographically, what the spatial and phylogenetic components are. Now we have a phylogeny for the plants, which did not exist at the time. Still, I have results from that period that no one else has managed to obtain in the same way since then.

What kind?
Seeing to what extent the diversity of two groups linked by a well-defined ecological relationship vary with each other. In these interaction studies, the nature of the observation varies a lot. One of the fronts that advanced most with the theory of complex networks, which has become so popular over the last 20 years, was the study of pollination. A pollination network includes observations of floral visitors, who may be legitimate pollinators, nectar thieves, clever, naughty…

Are you interested in the whole spectrum?
Strictly speaking, when it comes to mutualism, the association between two living beings, there has to be effective pollination. If we observe who visits the flower without verifying that they carry pollen, we are mixing those that provide a service to the plant with others that are just hitchhiking or are system parasites. Researchers use hand nets, insecticides, field vacuums – anything to collect those insects on the plants. I wanted to be sure of the association and concentrated on inflorescences, on which there is a great diversity of insects. The protocol I developed during my PhD was to raise the insects whose larvae were already inside the flowers. On my first trip, I put the flowers in popcorn bags that I hung from the clothes lines at the hotel. Only later did I begin using the jars I still use today. The first night, I already had insects in them. This speed gives you an idea of the order of magnitude of biodiversity in the tropics for organisms of this type. The database we established contains just the insects that developed on the inflorescence and continue to grow on it. For each day of fieldwork, we need one month to grow them all, one year to mount and separate them, and 10 years to identify them. Since I started 30 years ago, I have developed a very high level of identification for these insects.

Are they mainly flies?
Flies, micro-moths and beetles. We invested a lot in identification and for most families, we’ve achieved state of the art, the best identification available. Since I performed most of the identifications before the current legislation, I visited the National Museum of Natural History in Washington DC several times, carrying only a small suitcase of clothing and a large suitcase full of plant and animal matter I had collected. I would go to the third floor to ask questions about the plants, to the sixth floor to identify the insects, and worked one or two weeks with specialists in each group. In most cases, the state of the art is very good and we were able to determine species and even describe new ones. Together with colleagues from Germany, we’re focusing on a genus of flies to clarify the genetic and morphological variation of their association with host plants, with the possibility of seeing if bacteria from the intestinal tract mediate this relationship.

Espinhaço Mountains: in 1995 with Bruno Buys, Paulo Inácio Prado and Vinicius Motta...

Personal archive Espinhaço Mountains: in 1995 with Bruno Buys, Paulo Inácio Prado and Vinicius Motta…Personal archive

Is this is the front line of what you are doing now?
We’re also developing theory – reconceptualizing the idea of ecological specialization. I began developing a generalization of the entropy model for the diversity of interactions while pursuing my doctorate.

How does it work?
Entropy is a physics concept and has to do with the organization of energy levels. In the mathematical theory of communication developed in the late 1940s, entropy was used to assess uncertainty and errors in the transmission of information. A system is more diverse if it has more components, but also if it has greater organization of the connections between the components, of the ecological interactions between them. If all species are connected to each other, an intricate network is formed without a proper structure. However, systems of living organisms are usually highly structured: most species have strong interactions with a very small number of other species. It is precisely the organization of these interactions that is interesting to a growing number of ecologists. This idea compares two approaches to organization that result in what some colleagues have called biodiversity architecture. They constitute different ways of organizing interaction systems, one with many links between elements and another in which there are fewer connections, but the links are grouped together. The dynamics of these systems is very different.

What does this have to do with system vulnerability?
In principal, if you perturb one point in a highly interconnected system, this perturbation can propagate throughout the entire set of species. If the entities interact strongly with groups that are isolated from each other, this restricts the spread of a perturbation. When we talk about changes, we might be referring to those that are introduced through the arrival of a pathogen in an ecological community where the disease had not previously existed. The more specialized the relationships, the fewer alternative reservoirs or predators. If there is a strong impact reducing a predator species, such as the jaguar, this allows a significant increase in the populations of other animals that were once their prey, such as the opossum. The effects will depend on what the opossums eat: the broader their interactions with other species, by eating seeds or other animals, the more widely these effects will propagate. Understanding the structure of these interactions is a way to better explain and increase our ability to predict the effects of different changes.

What is the relationship between this and your study of the interactions between insects and plants?
I want to see the configuration of interactions. One plant can be eaten by just one insect, and another by several, and vice-versa: specialization in both directions. It was very clear to me, even during my doctorate, that my observational focus is the interaction itself, but I collected organisms because I needed to identify them. I am in Brazil, so most of them are unknown or are new species. This means we must archive material and establish a reference collection.

But these organisms are not the most popular, right?
The major conservation efforts focus on fascinating animals, of the type used in logos and things like that. This ends up guiding conservation initiatives towards those species. You may have biological reserves with popular support oriented towards saving a particular species, such as the eagle, a symbol of the United States. On the other hand, if you revisit the Convention on Biological Diversity, there is a commitment to preserving, restoring and sustainably using ecological systems to protect processes and maintain services. This benefits human quality of life. The panda is an icon, but it is not necessarily important for ecological services. The inventories of zoologists and botanists do not provide the short-term answers we need, because the planet is rapidly degrading. We need something else. Many work based on the premise that, if we save the big cats, we will be preserving most of the other processes, because they act as umbrella species that harbor other species and ecosystem processes. But that’s not exactly how it works.

What did you work on during your academic residence in Bellagio, Italy?
I proposed developing an operational introduction on how to deal with biodiversity, something that works for people from other fields. The idea is to divide the biota into three large categories: macro, meso and micro. The large organisms are essentially flowering plants and  vertebrates, with some honorary members like butterflies and ants. They are large organisms for which the taxonomy is very advanced and essentially complete. At the other end, micro, we have uncovered only the tip of the iceberg, but molecular methods are causing a revolution. Part of this is understanding microbial diversity through molecular libraries and methods centered on DNA or RNA, without relying on conventional biological classification. The middle category is more complicated, because the procedure is to describe species, but there is a huge number of them in this group. My point is that each of these three groups has important properties that allow us to understand and work with biodiversity. If you want to map species, you have to look at the macroorganisms. If you want to focus on ecosystem processes and services, you have to prioritize the microbiota. Fungi and bacteria in the soil and water are essential to these processes. There are direct links between soil diversity and the functional properties of earth. The middle category, arthropods and other small organisms visible to the naked eye, is vital to capturing the architecture of interactions and tracking certain processes like pollination, dispersion and feeding. Each group provides information on one scale of the environment. Birds can easily fly between forest fragments because to them the fragments are not isolated. But for soil organisms, each fragment is an island with different spatial dynamics.

...and in 2016 with Leonardo Jorge, Camila Leal and Prado

Personal archive …and in 2016 with Leonardo Jorge, Camila Leal and PradoPersonal archive

How does this apply to conservation policies?
First you need to understand what is happening, and then formulate ways to monitor, intervene or follow up on the effects of your interventions. All of this leads not only to determining public policy, but also to policies for use of resources.  Public and private. My basic proposition is that any more-comprehensive program has to have a percentage of resources allocated to microbiota, another to mesobiota and yet another to macrobiota. Which group in each case will depend on opportunities and on who is available to do the work.

And from the international point of view?
This varies. The United States has a lot of diversity and a lot of science. In Northern Europe, there is an extremely high density of knowledge about biodiversity, but biodiversity itself is low. Among the highly diverse countries, there is a wide range of scientific resources. Some countries do not even have a university research system. We can share the experience of countries like Brazil that have high diversity and institutionalized science. I have had a short list in my pocket for a while now: Mexico, South Africa, Australia and India. In my opinion, it would be worthwhile to try to organize a special South-South meeting with these countries. South Africa and Australia have advanced systems to map species. This is closer to what we have than what the Finns have. It is easy to study the biodiversity of Finland. In Australia, it’s not as easy.

How can you use the knowledge that scientists in each country develop for public policy?
There are two fictitious ideas that must be eliminated. One is the idea that science for science’s sake solves all problems; that scientists tell others what to do. This does not work. At the other extreme is the idea — almost anti-science — that science is a narrative like any other. It isn’t. Somewhere in between these two extremes lies a space in which we can present solid knowledge; reliable evidence for developing policy. I think we are very far from this. Look at the Forest Statute. It has critical gaps, but it helps if we work with knowledge and decent evidence, using science not like truths that have been revealed, but to provide working models that create a bridge between theoretical and experimental research. The Forest Statute was well-intentioned in the 1960s. The update this decade was needed, but the science invoked was a horror story of impending crises with regard to food production and economic. Either we make environmental legislation compatible with food production needs, the small property crisis, and export requirements, or Brazil deteriorates. The studies used to support these arguments were not published in serious periodicals, but they served to promote obvious interests.

So the science that could take advantage of ecology to maintain long-term productivity was ignored?
It was marginalized. They claim it was heard, but this is false. The list of individuals invited by the commissions to talk to Congress was large, and contained a series of scientists. But, when I tried to find the testimony, the list was shown to be fiction. It seems that most of the researchers were not called. The most relevant science was not considered. It is a constant struggle to have ecology recognized as a science like all others, for better or for worse. If a person talks about the chemistry of materials, we can discuss if he is a good scientist or not, but no one says that he is not a scientist. Ecologists tend to be dismissed as environmentalists. So we prepared a document that is being distributed to prosecutors, congressional aides and government agencies. The information needs to be presented in more effective ways, and should be applied to science teaching. I worked on science books years ago, taking photographs, and this was very important in my training.

Do you still take photographs?
I’m getting back into it, but I need to find time to do it more seriously. It’s a pleasure to take photographs in the little time available when I do fieldwork. I also do what some people call authorial photography. Over the last six or seven years I began to take photos, mostly on beaches. I grew up on the beach. Walking barefoot on the sand with a camera is great. Two of my aunts were artists. One died in 2001 and the other is still active despite her age — 82. The latter, Anna Bella Geiger, works with fine arts, chiefly engraving, but she also works with mixed media, and was one of the first artists to work with video. My other aunt was better known as an engraver, Fayga Ostrower. Their work is represented in the archives of the largest museums in the world. From a young age I had a lot of contact with Fayga, who was my mother’s oldest sister. I have childhood memories of seeing her work, since it was part of family visits, and noting its evolution. I even worked with Anna Bella on a conceptual project. I began to reflect on what this very early experience represented in relation to my way of seeing things and taking photographs. Clearly, I am not trying to take photographs in a style similar to that of Fayga or Anna Bella, but my way of seeing things was influenced by them. I am thinking of using some of their engravings with my photographs to comment on the similarities and their influence on my way of looking at the world.

You are also a musician, right?
A dilettante. We have an early music group that plays mostly music from the 15th through 17th centuries. My upbringing involved a lot of music, and my family listened to classical music. When I was a teenager I started listening to folk, MPB, and fell in love with jazz and rock; I spent time listening to other things. This older style of music was not played very often when I was a child. But I participated in an amateur group in Rio. I saw a concert when I was 8 or 10 and fell in love with the instruments. It is easy for listeners to enjoy, with many delightful dances and short pieces. I find the timbres very pleasing.

Current composition of the early music group Zebu Trifásico (from left to right): André Freitas, Lewinsohn, Luciana Castillo, Paulo Dalgalarrondo, and Rafael Oliveira

Personal archive Current composition of the early music group Zebu Trifásico (from left to right): André Freitas, Lewinsohn, Luciana Castillo, Paulo Dalgalarrondo, and Rafael OliveiraPersonal archive

And you started researching the music of that period?
I started buying LPs. I attended an experimental high school in Niterói where non-academic  activities were also taken very seriously. I started playing recorder there. Later, because of jazz, I became part of a circle of extraordinary musicians in the 1960s. There was a saxophonist, Vitor Assis Brasil, an important figure in Brazilian jazz, Luizinho Eça, who founded Tamba Trio, and others. I received a saxophone as a gift around the time I took the university entrance exams. I remember rushing through the exams because I wanted to get back so I could play it. I began to take lessons from a friend, but my motivation dropped off during the dictatorship because these musicians left Brazil. I went back to the recorder and took lessons from a good recorder player in Rio, who was in Roberto de Regina’s group. When I went to England for my postdoctoral research, I joined a serious amateur group that had been playing together for a long time. We played Renaissance music, some early baroque music, and some pieces from the Middle Ages.

Was that when you began to explore other instruments?
No, I only played recorder there. When I returned, we formed the core of a group that varies over time, but André [Freitas, a professor in the same department] and I have been playing together for 25 years. We began to buy instruments, get them as gifts, borrow them. In addition to the recorders (sopranino, soprano, tenor, bass and great bass), we often play an instrument called a crumhorn, and other variations of it that later developed into the oboe. André has a precursor of the clarinet, I bought an instrument reconstructed based on engravings from the 17th century. It looks like an oboe, but it has a windcap similar to that of the crumhorn. André plays everything. He has bagpipes that are just like the kind played during medieval times. Last year I bought three cornamuses, which are a type of reed instrument. André and I would like to develop a phylogeny of these instruments. We even began to gather material, but haven’t had the time to devote to it yet.