The Desert Laboratory on Tumamoc Hill hosts a series of lectures focused on topics that relate to the science, ecology, history, and culture of the Sonoran Desert. All talks are open to the public.
Talks are presented in thematic series format in the fall and spring. Please direct any questions to tumamoc-hill@arizona.edu or (520) 621-6945.
Current Lecture Series

About our Presenters:
- Dr. Michael Kotutwa Johnson, is a member of the Hopi Tribe. Dr. Johnson is an Assistant Specialist- from the University of Arizona (UofA) within the School of Natural Resources and the Environment and is also affiliated with the UofA’s Indigenous Resilience Center and Cooperative Extension. Dr. Johnson is also a co-author of the Indigenous Chapter in the National Climate Assessment Five and peer-reviewed journal and feature articles. He continues to practice Hopi dry farming, a practice of his people for millennia. Visit Dr. Johnson's Instagram page and his profile with the Indigenous Resilience Center at the University of Arizona.
- Dr. Peter Breslin, Staff Researcher at the Desert Laboratory on Tumamoc Hill started his Ph.D. in Environmental Life Sciences at Arizona State University in 2014 after a 30-year career teaching secondary school. He finished the Ph.D. in 2020. His Ph.D. research involved the evolution, ancestral biogeography, and population viability of a group of cacti called the Mammilloid Clade, composed of plants commonly called "pincushions" and "fishhooks," including the locally common Cochemiea grahamii (formerly in Mammillaria). He has published three greatly revised chapters of his dissertation, in Ecology and Evolution, Taxon, and the American Journal of Botany. He is also the editor of The Cactus and Succulent Journal and the peer-reviewed annual, Haseltonia, published by The Cactus and Succulent Society of America. On Tumamoc Hill, Breslin is a postdoctoral researcher conducting the decadal survey of the saguaro plots set up in 1964 by Rod Hastings and Ray Turner. He hopes to use this extraordinary long-term data set, as well as data from the National Park Service and researchers in Mexico, to make projections about the future of the saguaro over the next 100 to 200 years.
- Dr. Charlotte Brown is a plant and community ecologist who uses experimental and analytical methods to examine the mechanisms of community assembly, species interactions, and diversity. Dr. Brown spent ten years in Canada conducting research and obtaining a B.Sc. (Dalhousie University) and
Ph.D. (University of Alberta).
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Previous Lecture Series
Health is strongly connected to our interactions with the spaces around us. Tumamoc Hill is emblematic of this relationship, a place where many experience a connection to nature, health, community, self, and others. The importance of these relationships have all been accentuated and challenged in the last year and half. A conscious relationship with the natural world, a critical factor in health, can help alleviate “nature deficit disorder” and help us find balance. Join us for a four-part lecture series that brings together voices in health, environment, community, and food to share emerging perspectives and practical suggestions about the critical role of natural spaces in health and healing.
Agave has been a mainstay of culture in the Americas for millennia: food, drink, tool, spirit, utilitarian, sacred. Adaptations to aridity represented by both agave and people hold critical insights into how to live in the desert. This lecture series looked closely at these adaptations and the reciprocal relationship between this desert plant and people. Through presentations, roundtable discussions, tastings, and art we collectively reconnected to the importance of agave, how this relationship is threatened by climate change and our actions, and also how a resilient future is embedded in the heart of a plant.
For this series, Club Congress and El Crisol offered tastings of agave spirits.
The Santa Cruz River was the life blood of the earliest human settlements in Tucson (Chukshon, O'odham, Black Base) but today has been downcut, drained, channelized, cemented, and ignored. Yet, innovative thinking and actions are working to reverse this trend and revitalize the Santa Cruz river where it once flowed perennially at the base of Tumamoc Hill, reinvigorating a lush ecosystem, the local watershed, and sense of place. This four-part lecture series explored how the river has coursed through the history of people in this region and how it can continue to do so into the future.
Tumamoc Hill | Cemamagi Du’ag has been a site of culture and gathering for thousands of years. In this lecture series we collectively learned from key voices about the vibrancy and essential connection between people and place. We now see the Hill of the Horned Lizard in a different way and appreciate its meaning through the millennia and into the future.
Did you know that the Sonoran Desert originated in part from the tropics? The Río Mayo drainage of the Sierra Madre mountains near Álamos, Sonora, Mexico, is a convergence zone of astonishing biological and cultural diversity. Research into this unique and imperiled ecosystem at the Desert Laboratory on Tumamoc Hill extends back to the 1940s. The Desert Laboratory and The Southwest Center hosted this series, ventured back to the Río Mayo, and heard from a diversity of researchers and community members who highlighted new explorations, biocultural understandings, and efforts to preserve the tropics next door.
La Vaquita Marina, a small porpoise endemic to the upper Gulf of California, is on the precipice of extinction. Global scale economic pressure fuels local gill-net fishing that ensnare the vaquita, driving their numbers down to as few as a dozen individuals remaining. This lecture series with experts from Mexico and the United States explored what lessons we can learn from an intertwined web of science, local and global economics, politics, black markets, and conservation. What can be taken from this dire situation for future conservation? Where does the middle ground exist and how do we get there?
Since the Hornaday expedition set off from the Desert Laboratory in 1907, captured in the book Camp fires on Desert and Lava, there has been a unique connection between Tumamoc Hill and this enigmatic volcanic range in NW Mexico. Recognized by many as the desert’s heart, the Pinacate has captivated and inspired those who have traversed its rugged slopes, peaks, and dunes. Four individuals connected the audience to this special region of our desert in celebration of the first bilingual publication of the 1928 novel Campos de Fuego: A Brief and Fantastic History of an Expedition into the Volcanic Regions of the Pinacate by Gumersindo Esquer, Contribution 2 of the Proceedings of the Desert Laboratory.
Interested in previous one-time lectures given at the Desert Laboratory? Check out our full archive of previous lectures!