Tumamoc Talks

The Desert Laboratory on Tumamoc Hill hosts a series of talks focused on topics that relate to the science, ecology, history, and culture of the Sonoran Desert. All talks are open to the public.

Wednesday, October 14th at 5:30pm

Ephemeral jewels: hydrology, ecology, and trails connecting the tinajas of the Pinacate

For vast portions of the western Sonoran Desert, tinajas provide the only available surface water for humans and wildlife. These bedrock-bound stream pools may hold water for weeks to over a year after significant rainfall events, but their hydroperiods (cycles of wetting and drying) vary across tinajas. Since 2019, we have studied dozens of tinajas across the Pinacate Biosphere Reserve and Organ Pipe Cactus National Monument to measure their hydroperiods, document their aquatic biodiversity, and their use by wildlife. Dozens of species of wildlife visit tinajas in both reserves, including bighorn sheep, mountain lions, skunks, golden eagles, and migratory birds -- and over 100 aquatic animal species live in their temporary waters. In the Pinacate, traces of ancient Hia-Ced and Tohono O'odham trails lead from tinaja to tinaja, demonstrating the deep cultural importance of these waterbodies as well. To more deeply connect with this landscape, and the tinajas hidden within it, we made a 5-day backpacking trip around the Pinacate volcano, hiking across lava flows and relying solely on tinajas for drinking water along the 50-mile route. This presentation will include both an overview of our scientific studies as well as a photographic travelogue of our backpacking trip across the incomparable Pinacate.   

Michael Bogan is a stream and riparian ecologist and an associate professor in the School of Natural Resources and the Environment at the University of Arizona. He has been on the faculty since 2016 and he was named the Cecil and Carol Schwalbe Endowed Chair in Cold-Blooded Research, Teaching, and Conservation in 2025. Michael and his students love and study nearly everything that lives in or near desert waters, including dragonflies, turtles, fish, and birds. Prior to his position at the University of Arizona, Michael did his graduate and postdoctoral studies at Oregon State University and the University of California, Berkeley, where he studied the impacts of stream drying and water management on aquatic biodiversity across Oregon, California, Arizona, and northern Mexico.

Location: The Tumamoc Hill Boathouse (base of the Hill)