Biology professor Rodolfo Dirzo began his talk for the “Growing Up in Science” seminar series at the Neurosciences Building on April 11 with a photograph, taken in his hometown of Cuernavaca, the lush capital of Mexico’s Morelos state. In it, a very young Dirzo poses for his professional portrait standing atop a skinned jaguar — an endangered species in Mexico. 

Dirzo proceeded to illuminate his formative years, recounting his journey from an environmental miscreant to becoming one of the leading scholars in the field of conservation biology, while highlighting the importance of trust and perseverance in protecting biodiversity. 

“I try to emphasize not only the beauty of science, but also recognition of the questions that we need to be paying attention to if we want to maintain this amazing beautiful planet,” Dirzo said. “If you really think about it, what we see is nothing but the product of four billion years of organic evolution. It is this incredible [natural] benefit that we have on this planet.” 

After many years of teaching at the National University of Mexico, Dirzo came to Stanford in 2005 with an understanding that he would “serve as a conduit between Stanford and Mexico,” he said. 

Maintaining his connection to his native country, Dirzo focuses on the study of species interactions in tropical ecosystems ranging from California to Latin America. His work aims to demonstrate the benefits of ecological science for humanity. Dirzo also conducts significant science education programs with underserved children in the Bay Area and his study sites. 

“I personally really admire Professor Dirzo,” said Kenna De La Rosa ’27, an aspiring conservation biologist. “He is just a really inspirational person for me, and seeing him have such a fruitful career path that I only recently discovered is really inspiring.” 

While Dirzo’s parents wanted him to pursue a more traditional career as a doctor or lawyer, he could not resist his profound attraction to nature from a young age.

As a biology major at the University of Morelos, Dirzo discovered his interest in plant evolutionary biology and assisted with a research project analyzing rates of deforestation and land use change around a mega reservoir dam that delivered water to Mexico City.

“I thought, ‘Wow, in addition to the beauty of going to these places, we can do something that can be useful,” Dirzo said. 

At the recommendation of a visiting professor from the U.K., Dirzo applied for grants to fund graduate school through the British Consul in pursuit of master’s and doctoral degrees at the University of Wales.

With a limited understanding of English, Dirzo initially struggled in his program and encountered prejudice in Wales. Applying “twice the amount of effort as other students,” he ultimately finished his master’s degree in record time and completed a Ph.D. focused on the chemical evolutionary defense adaptation system of white clover plants. 

“What I brought to that beautiful place was not English, but passion and commitment. I was full of perseverance. I had humility. I had a relentless dedication to listen and that helped a lot,” he said.

Upon his return to Mexico, Dirzo sought to apply his expertise to the complex ecological challenges in Veracruz, only to find that the plants he intended to study were absent from the local ecosystem due to considerable human activity. He discovered that the reduction of the forest was a reflection of the absence of wildlife, a phenomenon known as absent forest syndrome. 

“I [realized], if I don’t do anything about the conservation of this place, I will not be able to study the kinds of things that I’m fascinated by, like evolutionary defenses,” Dirzo said. “In some sense, I combined my interest in the evolution of plant and animal interactions with conservation. And that has been my career for the last several decades.”

Dirzo formulated a new term — defaunation — to describe the conditions he and other researchers saw in the forest, denoting the loss of species and populations of wildlife. A crucial driver of global ecological change in the Anthropocene, the term defaunation now appears frequently in conservation literature and has contributed to a fundamental reshaping of approaches to conservation science.

By affecting ecosystem processes and services, defaunation also has critical implications for humankind, according to Dirzo. In particular, the loss of global megafauna has led to the proliferation of smaller animals that are vectors of diseases. As these species have come into closer contact with humans due to habitat loss — a process accelerating under climate change — the transmission of global infectious diseases such as COVID-19 has become more widespread.

Beyond studying the conservation of nature, Dirzo has expanded the scope of his research to analyze the conservation of cultures. Describing the “double extinction process” of both biological and cultural diversity, Dirzo noted the correlation between the loss of species and ecosystems and the loss of languages and traditional knowledge. “My emphasis went from being a very Darwinian plant ecologist to trying to define the impact of humanity on nature and how that is relevant,” he said. 

With most of his work focusing on rural communities in the Global South, Dirzo has also served as the associate dean for environmental justice at the Doerr School of Sustainability. “All of these communities have beautiful biodiversity remaining, and they will be impacted dramatically, disproportionately by climate change,” he said. 

Dirzo also emphasized the necessity of building rapport and trust with indigenous and rural communities to avoid the pitfall of “helicopter science.” 

“You really need to spend time in the community… take advantage of the relationships that people have developed and spend the necessary time to be able to work with them at the speed of trust,” he said.

For the young scientists in the audience on Friday, Dirzo’s insights and experiences were inspiring. 

Marty Freeland ’27 has conducted ornithology research in Dirzo’s lab since age 12. “It was especially moving to hear Professor Dirzo share some of the background that has shaped him into such an extraordinary mentor — from his ordeals as a Spanish-speaking graduate student in Wales struggling to learn Welsh and English simultaneously to the process of convincing his family that ecological research is a worthwhile pursuit,” he said. 

“[Dirzo] has navigated nearly all the hurdles that his students may face and draws on those experiences to provide limitless support… he shows us by example that it’s possible to meet any challenge with humility and a sense of humor,” Freeland added.