Saguaro Water Balance
Tracking changes in volume:surface ratio (V:S) across seasons to understand how saguaros store and lose water, and how much rainfall is required to recharge a desiccated plant.
Saguaro water balance, desert heat, and plant function.
I am a plant physiologist and desert ecologist working on how Carnegiea gigantea (saguaro) and other Sonoran plants respond to heat, drought, and changing climate.
This site hosts project summaries, interactive figures, and opportunities for collaboration and public engagement.
About
I study the physiology and ecology of desert plants, with a focus on water relations, thermal stress, and long-term responses to a warming, drying climate. My work combines field measurements, and quantitative analysis to understand how iconic species like saguaro cacti are changing through time and how they will cope with a changing climate.
I am based in Phoenix, Arizona, and spend my time between fieldwork, lab management, data analysis, and public outreach. This site is a living space for current projects, visualizations, and ways to get involved.
Research Themes
Photosynthetic Performance & Stress
Monitoring FVFM (dark-adapted quantum yield) as a window into photosystem health, and relating it to temperature, humidity, vapor pressure deficit, and plant water status.
Climate & Extreme Heat
Using environmental variables (temperature, humidity, radiation, precipitation) to quantify the conditions saguaros experience.
Fieldwork & Collaboration
Inter-agency surveys, long-term monitoring, and collaborative projects that link fundamental plant physiology with conservation and management decisions in the Sonoran Desert.
Interactive Figures
These figures are built from ongoing analyses of saguaro physiology and microclimate. Hover and zoom to explore the data. New plots will be added as projects develop.
V:S, Daily Max Temperature, and Precipitation Through Time
Size-class averaged V:S with standard errors, overlaid with daily maximum temperature and precipitation.
FVFM, Daily Max Temperature, and Precipitation Through Time
Mean FVFM by size class with uncertainty, shown alongside daily temperature and rainfall.
FVFM vs Relative V:S (Medium Plants)
FVFM as a function of relative V:S (% of maximum), with a log-curved fit to highlight how photosystem performance changes as plants transition between “fat” and “dry” states.
Fieldwork & Outreach
This project is grounded in field measurements across South Mountain and other Sonoran sites, and in sharing what we learn with the public.
- Long-term monitoring of tagged saguaros across elevation bands.
- Nighttime FVFM campaigns to track seasonal stress and recovery.
- Sensor networks logging temperature, humidity, and radiation.
- Talks, guided walks, and educational materials on desert resilience.
If you are interested in collaboration, data use, or educational partnerships, please reach out.
Contact
For questions about the research, data visualization, or potential collaborations, you can reach me at:
Email: aschuessler@dbg.org
You can also connect with me on LinkedIn and other professional networks (linkedin.com/in/alexandra-schuessler).