Rodolfo Dirzo

From an “Ecologist Directory” maintained by the ESA Education Office about 2004-2005. Profile circa 2004.
Degree                                       Ph.D. (University of Wales)
Position                                     Tropical Ecologist
Department                               Instituto de Ecología
Organization                             Universidad Nacional Autónoma de México
Rodolfo Dirzo has long been fascinated with patterns in nature. From his childhood bugwatching in Mexico to his graduate studies with slugs and snails in Wales to a career in tropical ecology, Rodolfo has lots of experience explaining how different aspects of ecology fit together. When asked about the transition from the meadows of the United Kingdom back to Mexico’s lush forests, he points out that the principles of scientific research are universal.

“In England, so much is known about the local natural history. I could study complicated interactions because the system is so well described. With that experience, I was able to extend some of my ideas to tropical forests,  and began asking similar questions there.”
“In graduate school, I had the pleasure of being one of the last students of Professor John Harper  at the University of Wales. He had the interesting idea that plants are influenced by their environment-not just the physical environment, like temperature and elevation, but also other  living organisms. I wanted to look at animals as important components of the biology of plants. That hasn’t changed.”
After he completed his Ph.D., Rodolfo began working throughout Latin America. He was one of the first generation of students who attended the Organization for Tropical Studies’ Spanish-language courses in tropical biology. Taught in both Spanish and English, OTS participants are immersed in tropical studies at Costa Rican research stations. Rodolfo himself has taught sections of the Spanish-language courses for 15 years. The OTS courses allow Rodolfo to concentrate on one of  his primary interests: science education. He is particularly focused on reaching Latin American students. “Much of the world’s tropical rain forests and a substantial portion of global biodiversity are here, so I am dedicated to teaching with OTS and with a Central Amazonian ecology course in Brazil.”
In understanding natural patterns, Rodolfo teams scientific knowledge with imagination. To understand how the loss of biodiversity impacts tropical ecosystems, Rodolfo has to consider what has been altered in a forest where animals have been displaced. In this way, he hopes to describe some of the effects of habitat degradation and disturbance in the tropics.
“Many people study deforestation using satellite imagery and other tools. I am interested in forest defaunation, or the loss of animals in tropical ecosystems. We can talk about this loss, but we cannot see these things as readily as we can see deforestation. Animals are often nocturnal or secretive, so it is much more difficult to notice if animals are missing than it is to see large clear cuts or other forest disturbances. What we have to do then is look at the biology of plants in the area to see the effects of the absence of these animals.”
To do this, Rodolfo works in two research locations. Los Tuxtlas in Veracruz, Mexico is a known defaunated site, where many of the native animals are no longer found in expected quantities. His other site, Montes Azules, is in Chiapas, Mexico, where the local fauna is “perfectly intact.” By looking at natural patterns in each place, Rodolfo observes what may be the results of a loss of animal diversity. Further experiments help him determine whether the patterns he sees are due to defaunation, or some other ecological process.
As Rodolfo explains, “In the absence of animals, plants are not being eaten. Animals feed on seeds and they trample plants, creating natural disturbances. In the absence of these activities, many plant species have to compete for space on the forest floor. Dominant species, or those best equipped to survive under these changing conditions, monopolize the forest understory. Since the understory is essentially made up of babies of the big trees, what grows up there will be the forest of the future. In other words, defaunation may lead to a reduction of forest diversity in the future.”
When thinking about his career as an ecologist, Rodolfo speaks highly of the scientists who have served as mentors in his life. His mentor in Mexico, Professor Jose Sarukhan, his graduate professor John Harper and tropical ecologist Dan Janzen each played a significant role in shaping Rodolfo’s ideas and his research. Serving as director of Los Tuxtlas Research Center in Veracruz also ranks among the most important experiences of Rodolfo’s career. “I had already gained the formal classroom training and field research experience, but the perspective of living in the place itself, getting to know the forest and seeing the problems first-hand closed the circle of experiences I’ve had in tropical ecology.”
Whether working with Welsh snails or with tropical animals, Rodolfo has found ecology to be tremendously rewarding. “We need a scientific baseline to guide us through the very difficult problems the environment is facing nowadays.”
“As important as it is for ecologists to do rigorous science and to communicate their findings to the scientific community, an equally important element is divulgacin. The closest term in English is dissemination, but what this really means is the spreading out of information to the public. This is a crucial responsibility that we as ecologists have. Sometimes ecologists do not have the time or talent to do this, but it is a major need for the future.”
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